The source water trap: base EC vs. nutrient EC
A common source of confusion is failing to subtract your Base EC (the reading of your plain water) from your Total EC. If your tap water has an EC of 0.4 and your goal is a nutrient strength of 1.4, your meter should read 1.8. This distinction matters because every ion in your water contributes to the conductivity reading, whether those ions come from your nutrient concentrate or from the municipal water supply.
However, if you are using Reverse Osmosis (RO) water, your base EC is effectively 0.0. In this case, your target and total EC are the same. This calculator lets you input source water so you can see exactly how much “actual feed” is in your system versus background minerals from the tap. Growers who ignore this distinction routinely underfeed when they assume their total reading equals nutrient strength, or overfeed when they add nutrients on top of already-high source water without accounting for the baseline.
The practical impact is significant. Consider two growers both targeting 1.6 EC for mid-vegetative growth. Grower A uses RO water (base EC 0.0) and mixes to 1.6 EC total—all of that reading is nutrients. Grower B uses well water (base EC 0.6) and also mixes to 1.6 EC total—only 1.0 EC of that reading is nutrients. Grower B is actually underfeeding by nearly 40% compared to Grower A despite identical meter readings. This is why the source water input on this calculator exists and why you should always measure your base water before mixing.
“Plants don’t eat EC; they eat individual ions. High base EC from hard water often contains calcium and magnesium that can unbalance your carefully measured nutrient recipe.”
EC, PPM 500, and PPM 700: the definitive conversion guide
The hydroponic industry uses three different scales to express the same measurement, and this causes more unnecessary confusion than almost any other topic in growing. Understanding why multiple scales exist and how to convert between them will save you from expensive mistakes and wasted troubleshooting time.
EC (Electrical Conductivity) is the actual physical measurement your meter takes. It measures how well your solution conducts electricity, expressed in milliSiemens per centimeter (mS/cm). Every TDS or PPM meter on the market first measures EC internally, then applies a conversion factor to display a PPM number. EC is the universal standard used by commercial growers, agricultural researchers, and nutrient manufacturers outside of North America.
PPM 500 (TDS 500, NaCl scale) multiplies EC by 500. A solution reading 1.0 EC displays as 500 ppm on a meter using this scale. Hanna Instruments meters commonly use the 500 scale. This is the more common conversion in the United States and is what most American nutrient brands reference in their feed charts.
PPM 700 (TDS 700, KCl scale) multiplies EC by 700. A solution reading 1.0 EC displays as 700 ppm on this scale. Truncheon, Bluelab, and many European meters default to the 700 scale. Many Australian and European feed charts reference this conversion factor.
The conversion formulas are straightforward:
- EC to PPM 500: EC × 500 = PPM (NaCl scale)
- EC to PPM 700: EC × 700 = PPM (KCl scale)
- PPM 500 to EC: PPM ÷ 500 = EC
- PPM 700 to EC: PPM ÷ 700 = EC
- PPM 500 to PPM 700: PPM 500 × 1.4 = PPM 700
- PPM 700 to PPM 500: PPM 700 ÷ 1.4 = PPM 500
To identify which scale your meter uses, prepare a solution with a known EC (using calibration solution), then check whether the PPM reading is EC × 500 or EC × 700. Most meters also state the conversion factor in their manual or settings menu. Some advanced meters allow you to switch between all three scales.
Here is a quick reference table of common target values across all three scales:
- Seedlings / clones: 0.4–0.8 EC • 200–400 PPM 500 • 280–560 PPM 700
- Early vegetative: 0.8–1.2 EC • 400–600 PPM 500 • 560–840 PPM 700
- Late vegetative: 1.2–1.6 EC • 600–800 PPM 500 • 840–1120 PPM 700
- Transition: 1.4–1.8 EC • 700–900 PPM 500 • 980–1260 PPM 700
- Early flower/fruit: 1.6–2.0 EC • 800–1000 PPM 500 • 1120–1400 PPM 700
- Peak flower/fruit: 1.8–2.4 EC • 900–1200 PPM 500 • 1260–1680 PPM 700
- Late flower/ripening: 1.4–1.8 EC • 700–900 PPM 500 • 980–1260 PPM 700
- Flush: 0.0–0.4 EC • 0–200 PPM 500 • 0–280 PPM 700
EC is the professional standard because it eliminates conversion ambiguity. If you communicate in EC, every grower on the planet knows exactly what you mean. If you say “800 ppm,” nobody knows whether you mean 1.6 EC or 1.14 EC without asking which scale you are using.
How to read and interpret feed charts
Nutrient manufacturer feed charts are the starting point for any recipe, but treating them as gospel without understanding their assumptions is one of the fastest paths to plant problems. Every chart is built on a set of hidden assumptions that you need to decode before applying the numbers to your garden.
Anatomy of a feed chart: Most charts are organized into columns by growth stage (clone, veg week 1, veg week 2, flower week 1, etc.) and rows by product in the nutrient line. Each cell shows a dosage, usually in mL per gallon or mL per liter. The chart may also show a target EC or PPM for each column, which represents the expected reading after all products in that column are mixed into water.
Light, medium, and heavy feed: Some manufacturers provide tiered feeding schedules. “Light” typically means 50–75% of the full chart dose, aimed at sensitive strains, small plants, or growers using enriched source water. “Medium” is the baseline recommendation at roughly 75–100% strength. “Heavy” is 100–125% strength, intended for aggressive growers running high-light, high-CO2 environments with vigorous cultivars. Start at the light end and increase only if the plants ask for more through healthy growth without tip burn.
Most charts assume RO water. This is the single most important hidden assumption. If a chart targets 1.4 EC and you are building on tap water with a base EC of 0.5, following the chart exactly will put you at 1.9 EC total. You need to either reduce nutrient doses proportionally or subtract your base EC from the chart target and aim for that nutrient-only EC value. This calculator handles that math for you.
Translating between brands: Different brands formulate at different concentrations, so you cannot swap one brand’s dose rate directly into another brand’s schedule. Instead, compare target EC values. If brand A targets 1.4 EC in week 3 of flower and brand B targets 1.6 EC in the same stage, the difference is the brand’s recommendation for concentration, not a difference in measuring. Mix to EC targets, not to mL amounts, when switching products.
Adjusting for hard water: If your source water contains significant calcium and magnesium (above 150 ppm combined Ca + Mg), you should reduce or eliminate any supplemental cal-mag in the feed chart, potentially switch to a “hard water” formulation from your nutrient brand, and lower the overall dose rate to compensate for the conductivity your tap water contributes. Always measure your finished reservoir EC against the chart target, not the individual dose amounts.
Crop-stage nutrient strength targets
Plants have dramatically different nutritional needs at each stage of growth. Feeding a seedling at peak-flower EC will burn roots and stunt growth; feeding a fruiting plant at seedling EC will produce pale, undernourished results. These ranges are general guidelines for most hydroponic crops and should be adjusted based on species, cultivar, environment, and plant response.
- Seedlings and clones (0.4–0.8 EC): Young plants have tiny root systems with limited capacity to absorb nutrients. High EC at this stage causes osmotic stress, where water moves out of root cells instead of in because the external solution is more concentrated than the plant’s internal fluids. Start at the low end (0.4 EC) and increase gradually as roots develop. Clones are particularly sensitive because they have no root system at all initially and rely on turgidity from leaf absorption and stem reserves.
- Early vegetative (0.8–1.2 EC): Once roots are established and new growth is actively pushing, the plant can handle a moderate increase. Nitrogen demand ramps up significantly during this stage as the plant builds stems, branches, and leaf mass. Watch for dark green leaves (overfed) or pale new growth (underfed) to fine-tune your position within this range.
- Late vegetative (1.2–1.6 EC): Mature vegetative plants with robust root systems are actively building structural biomass and can handle higher nutrient concentrations. This is the stage where plants establish the framework that will support flowers and fruit. Strong vegetative growth at appropriate EC sets up the yield potential for the remainder of the cycle.
- Transition (1.4–1.8 EC): The period where plants shift from vegetative to reproductive growth involves a gradual change in nutrient ratios (less nitrogen, more phosphorus and potassium) and a moderate increase in overall strength. The plant is simultaneously finishing structural growth and beginning reproductive development, so nutrient demand is high across the board.
- Early flower/fruit (1.6–2.0 EC): Flower and fruit initiation requires increased phosphorus and potassium while nitrogen drops. Overall EC climbs because the plant is now supporting both established vegetative mass and new reproductive structures. Monitor for the earliest signs of tip burn, which indicates you have found the ceiling for your cultivar and environment.
- Peak flower/fruit (1.8–2.4 EC): Maximum nutrient demand occurs during peak reproductive development. Plants running supplemental CO2 and high light intensity can often tolerate the upper end of this range (2.2–2.4 EC) because faster photosynthesis drives faster nutrient uptake. Standard-environment gardens should stay at the lower end. This is where precision matters most because overfeeding reduces quality while underfeeding limits size.
- Late flower/ripening (1.4–1.8 EC): As fruit matures and flowers ripen, nutrient demand decreases. Reducing EC during this stage encourages the plant to mobilize stored nutrients from leaves into reproductive structures and can improve flavor, aroma, and overall quality in many crops. A gradual ramp-down over 1–2 weeks is preferable to an abrupt cut.
- Flush (0.0–0.4 EC): Whether or not flushing improves final product quality is debated, but many growers run plain water or very dilute solution for the final days of a crop cycle. The goal is to allow the plant to use up internal nutrient reserves. If you flush, use water at the same pH and temperature you would normally use; only the EC changes.
These ranges assume healthy plants in a well-managed environment. Stressed plants, hot temperatures, low light, or poor root health all reduce a plant’s ability to handle high EC. When in doubt, err on the low side and increase based on plant response rather than chasing a number.
Source water analysis: what the numbers mean
Every hydroponic operation should start with a water quality report. Municipal water suppliers publish annual reports (often called Consumer Confidence Reports), and well water can be tested through agricultural extension services or private labs. Understanding what these numbers mean is essential for building reliable nutrient recipes.
- Calcium (Ca): Contributes to EC and is a required plant nutrient, but excess calcium competes with magnesium and potassium uptake. Source water above 80–100 ppm calcium often means you should reduce or eliminate supplemental calcium from your nutrient line.
- Magnesium (Mg): Also contributes to EC and is essential for chlorophyll production. High magnesium in source water (above 30–40 ppm) can lead to antagonism with calcium uptake. A healthy Ca:Mg ratio in solution is generally 3:1 to 5:1.
- Sodium (Na): Not used by plants in significant quantities and accumulates in the root zone over time. Source water above 50 ppm sodium is problematic for most hydroponic crops. Sodium contributes to EC but provides no nutritional value, making your meter reading misleadingly high. There is no practical way to remove sodium except through reverse osmosis or distillation.
- Chloride (Cl): Plants need trace amounts, but high chloride (above 100 ppm) is toxic to many species. Like sodium, chloride raises your EC reading without contributing useful nutrition. Chloride and sodium together are the main reason brackish or coastal water requires RO treatment.
- Bicarbonates (HCO3) and alkalinity: Bicarbonates are the primary driver of water alkalinity, which is the water’s ability to resist pH change. High alkalinity (above 150 ppm CaCO3 equivalent) means you will use more pH-down acid, and your solution pH will drift upward faster. Alkalinity is not the same as pH. Water can have a pH of 7.0 but very low alkalinity (RO water) or a pH of 7.5 with very high alkalinity (limestone aquifer well water). The former is easy to pH-adjust and stays stable; the latter fights you constantly.
- Iron (Fe): Source water iron above 0.3 ppm can stain equipment and clog drippers. More importantly, iron in source water is typically in ferrous (Fe2+) form that oxidizes to ferric (Fe3+) when exposed to air, forming insoluble precipitates that are unavailable to plants and can block irrigation lines.
When is source water “too hard” to use? As a general rule, if your source water EC exceeds 0.5–0.6, if sodium exceeds 50 ppm, or if total dissolved solids exceed 300 ppm, you should strongly consider RO filtration or blending RO with tap to bring your baseline into a usable range. The cost of an RO system is almost always less than the cost of fighting water quality problems throughout every crop cycle.
Calibrating and maintaining EC/PPM meters
Your EC/PPM meter is the single most important instrument in your grow. An inaccurate meter makes every nutrient decision unreliable, and the consequences compound over time. Proper calibration and maintenance are not optional.
Calibration solution types: EC calibration solutions come in standard values like 1.413 mS/cm (1413 μS/cm) and 2.764 mS/cm. For hydroponic use, 1.413 is the most common single-point calibration standard because it falls in the middle of the typical working range. Two-point calibration using both 1.413 and 2.764 provides greater accuracy across a wider range and is recommended for professional operations.
Calibration frequency: Pen-style meters should be calibrated at least weekly for active grows, or before every use if you are making critical adjustments. Inline monitors should be calibrated monthly or whenever readings seem inconsistent with plant behavior. Always calibrate after replacing a probe, after extended storage, or after the meter has been dropped or exposed to extreme temperatures.
Probe storage: EC probes should be stored clean and dry (unlike pH probes, which must be stored in storage solution). Rinse the probe with distilled or RO water after every use and allow it to air dry. Never leave an EC probe sitting in nutrient solution between uses, as mineral deposits will build up on the electrodes and cause drift.
Probe replacement: EC probe electrodes degrade over time. Pen-style meters with non-replaceable probes typically last 1–2 years with regular use. Meters with replaceable probes should have the probe swapped annually in a commercial setting or whenever calibration becomes erratic (the meter cannot hold calibration or requires increasingly large offset corrections).
Common meter errors and how to identify them:
- Reading drifts immediately after calibration: Usually a dirty or damaged probe. Clean with a probe cleaning solution or replace.
- Reading is temperature-sensitive beyond normal: The ATC (Automatic Temperature Compensation) sensor may be failing. Test by measuring the same solution at different temperatures; readings should be consistent within 0.05 EC.
- Reading is stuck or unresponsive: Air bubbles on the probe, a dead battery, or a cracked probe. Tap gently to dislodge bubbles, replace batteries, or inspect the probe for physical damage.
- Reading is consistently high or low after calibration: Contaminated calibration solution. Always use fresh calibration solution from a sealed container; never pour used solution back into the bottle.
Cheap meters cost more in the long run. A $15 pen meter that drifts 0.3 EC without you noticing will cause more crop damage than the $150 professional meter would have cost. Budget meters are acceptable for hobbyists who calibrate frequently and cross-reference with a second meter, but commercial operations should invest in lab-grade instruments from Bluelab, Hanna, or Milwaukee.
The relationship between EC, pH, and nutrient availability
EC and pH are the two pillars of hydroponic nutrient management, and they are deeply interrelated. Measuring one without the other gives an incomplete picture. You can have perfect EC and still see deficiency symptoms if your pH is locking out the nutrients your plants need.
The pH sweet spot for hydroponics is 5.5–6.5. Within this range, all essential macro and micronutrients are reasonably available to plant roots. As pH moves outside this window, specific nutrients become chemically unavailable regardless of how much is dissolved in the solution:
- Below pH 5.0: Manganese and aluminum can become toxic. Calcium and magnesium availability decreases. Phosphorus may become more available initially but at the cost of micronutrient toxicity.
- pH 5.5–5.8: Iron, manganese, boron, copper, and zinc are highly available. This is the optimal range for iron-hungry crops and early growth stages.
- pH 5.8–6.2: The broadest range of nutrient availability. Nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur are all well-available. This is the most commonly recommended target for general-purpose hydroponic growing.
- pH 6.2–6.5: Calcium and magnesium availability peaks. Iron and manganese start to decrease. This range can be useful during fruiting stages when calcium demand is high.
- Above pH 7.0: Iron, manganese, copper, zinc, and boron become increasingly locked out. Phosphorus begins to precipitate with calcium, forming insoluble calcium phosphate that is unavailable to plants and can cloud your reservoir.
pH drift as a diagnostic tool: The direction your solution pH moves between adjustments tells you something about what the plant is doing. When plants absorb more cations (positively charged ions like potassium, calcium, ammonium), they release hydrogen ions, driving pH down. When they absorb more anions (negatively charged ions like nitrate, phosphate, sulfate), they release hydroxyl ions, driving pH up. Rapidly falling pH during vegetative growth often indicates heavy ammonium nitrogen uptake. Rising pH during fruiting often indicates heavy nitrate and phosphate uptake. Stable pH usually means balanced uptake.
Why chasing perfect EC at wrong pH is counterproductive: Imagine your meter reads exactly 1.6 EC, your target for mid-flower. But your pH has drifted to 7.2. At that pH, iron is nearly locked out, phosphorus is precipitating, and micronutrient availability is severely reduced. The plant shows iron chlorosis (yellowing between leaf veins) and phosphorus deficiency (purple stems, slow flower development). A grower who only watches EC might increase nutrient concentration to “fix” the deficiency, pushing EC to 2.0 or higher. This makes the problem worse because the additional nutrients still cannot be absorbed at pH 7.2, and now the elevated EC is also causing osmotic stress. The correct fix is always pH first, EC second.
Hard water nutrient formulations vs. standard formulations
Many professional nutrient manufacturers offer “hard water” versions of their base nutrients. Understanding when to use them and why they exist can save you from persistent nutrient imbalance problems that are difficult to diagnose.
When to use hard water formulations: Switch to a hard water version when your source water calcium exceeds 70–100 ppm or when your total water hardness exceeds 200 ppm (as CaCO3 equivalent). Hard water formulas contain less calcium (since your water already supplies it) and often include additional chelated iron and other micronutrients that compete with calcium for uptake.
How excess calcium and magnesium affect nutrient balance: Cation competition is a real phenomenon in plant nutrition. Calcium, magnesium, and potassium all compete for the same uptake pathways in roots. When calcium dominates the solution (as it does in hard water), magnesium and potassium uptake can be suppressed even when those nutrients are present at adequate concentrations. This is why growers using hard tap water sometimes see magnesium deficiency (interveinal chlorosis on older leaves) despite their nutrient formula containing plenty of magnesium. The calcium in the water is simply out-competing it.
Cal-mag supplements with RO water: The flip side of the hard water problem is RO water, which contains virtually no calcium or magnesium. Most hydroponic nutrient base formulas include some calcium and magnesium, but often not enough when starting from zero. This is why cal-mag supplements exist. A typical RO-water recipe adds 1–2 mL/L of cal-mag before adding base nutrients, targeting approximately 150–200 ppm calcium and 50–70 ppm magnesium in the finished solution. Always add cal-mag first, then base nutrients, to avoid precipitation from high local concentrations when concentrates interact.
A clean workflow for translating feed charts
Start by identifying the chart’s language first: EC, PPM 500, or PPM 700. Then confirm whether the chart assumes soft water, RO water, or already includes a base EC from tap. Once you know that, compare your current meter reading against the chart target in the same scale, then decide whether the real change you need is in total solution strength or in feed above source.
- Use total-reading mode when your target comes from a finished reservoir number.
- Use feed-only mode when the target is nutrient strength above source water.
- Re-check after major source-water changes because seasonal tap water can move your baseline.
- When switching nutrient brands mid-cycle, compare EC targets stage-by-stage rather than copying mL dosages from the old chart to the new one.
- Always verify the chart’s PPM scale. A chart targeting “1200 ppm” could mean 2.4 EC (PPM 500 scale) or 1.7 EC (PPM 700 scale), a 40% difference in actual nutrient strength.
Why hard water can fool otherwise good growers
Two reservoirs can read the same total EC and still behave differently if one is built on hard tap and the other on low-mineral water. Background calcium, magnesium, bicarbonates, and sodium all contribute to conductivity, but they do not behave like a perfectly balanced feed recipe. That is why separating source water from nutrient contribution gives a more honest comparison.
If your base EC is consistently high, this page is most useful as a translation layer. It tells you whether the recipe is actually stronger or weaker, independent of meter scale noise and background minerals that can otherwise hide the real nutrient delta.
Monitoring nutrient strength over time
Nutrient management is not a set-and-forget exercise. EC changes between reservoir changes, and the pattern of that change is one of the most valuable diagnostic tools available to a hydroponic grower.
EC rising over time: This means the plants are drinking more water than they are consuming nutrients. The remaining solution becomes more concentrated as volume drops. This is common in hot environments, with high transpiration rates, or when EC is set too high for the current growth stage. The solution is to lower your starting EC slightly and top off the reservoir with plain pH-adjusted water between full changes.
EC dropping over time: This means the plants are consuming nutrients faster than they are consuming water. This is generally a sign that the plants could handle a slightly higher starting EC. It is most common during peak growth phases when nutrient demand is high. A moderate drop (0.1–0.3 EC per day) is normal and healthy during vigorous growth.
EC staying stable: This is the ideal scenario. It means your nutrient strength is matched to the plants’ current uptake rate, and water and nutrient consumption are proportional. When EC holds steady, you have found the sweet spot for your current growth stage and environment.
How often to check: In recirculating systems, measure EC at least once daily. In drain-to-waste systems, measure both the input solution and the runoff. The difference between input and runoff EC tells you about root-zone accumulation: runoff EC significantly higher than input EC means salts are building up in the media and you may need to flush or reduce input strength. Aim for runoff EC within 0.2–0.5 of input EC.
Reservoir change frequency: Most growers change reservoirs every 7–14 days in recirculating systems. Even if EC and pH are within range, nutrient ratios shift as plants selectively absorb some elements faster than others. Topping off with concentrated nutrient solution can maintain EC but does not restore the original nutrient balance. Regular full changes are the only way to ensure ratio integrity.
Troubleshooting nutrient strength problems
When plants are not responding as expected to your nutrient program, the issue often is not EC itself but something interfering with the plant’s ability to use the nutrients at that EC. Here are the most common scenarios and how to diagnose them.
Plants look hungry at correct EC:
- pH lockout: The most common cause. Check pH before adjusting EC. If pH is outside 5.5–6.5, correct it first and observe for 48–72 hours before changing nutrient strength.
- Root health: Damaged, diseased, or oxygen-starved roots cannot absorb nutrients regardless of concentration. Check root color (healthy roots are white to cream; brown, slimy roots indicate problems), dissolved oxygen levels, and reservoir temperature. Root zone above 24°C (75°F) dramatically reduces oxygen solubility and promotes pathogen growth.
- Temperature stress: Both air and root zone temperature affect nutrient uptake. Cold roots slow absorption; hot roots damage cellular membranes. Optimal root zone temperature is 18–22°C (64–72°F).
- Antagonistic nutrient ratios: Excess of one nutrient can block uptake of another even at correct total EC. High potassium blocks calcium; high calcium blocks magnesium; high phosphorus blocks zinc and iron. This is a ratio problem, not a concentration problem.
Plants burning at low EC:
- Hot spots in the media: In drip and media-based systems, uneven irrigation can create zones of salt accumulation even when the input EC is low. The solution is more frequent irrigation with adequate runoff to prevent accumulation.
- Poor mixing: If nutrients are not thoroughly mixed before delivery, some plants may receive concentrated solution while others receive dilute. Always mix thoroughly and verify EC from the delivery point, not just the reservoir.
- Light stress mimicking nutrient burn: Excessive light intensity causes leaf bleaching and margin curling that can look like nutrient burn. If tip burn appears only on the canopy closest to lights while lower foliage looks healthy, the problem is light, not nutrients.
- Foliar spray residue: Foliar products left on leaves under intense light can cause localized burn spots that mimic nutrient toxicity.
EC won’t stabilize:
- Reservoir leaks: If your solution volume is decreasing faster than expected, concentrated solution is being lost and replaced with top-off water, causing EC to swing. Check fittings, plumbing, and the reservoir itself for drips.
- Inconsistent source water: Municipal water quality varies seasonally and sometimes daily. If your base water EC changes between mixes, your finished solution will be inconsistent. Measure source water EC every time you mix to catch these shifts.
- Poor mixing practice: Adding concentrated nutrients directly to a partially full reservoir without adequate stirring creates layers of high and low concentration. Always add nutrients to a full or nearly full reservoir with active circulation.
- Organic additives decomposing: Organic supplements (humic acids, kelp extracts, beneficial microbe foods) can change EC as they break down. If you use organic additives, expect more variability and measure EC more frequently.
Professional nutrient management workflow
Commercial operations cannot afford to guess. Here is a complete monitoring and adjustment routine used by professional hydroponic facilities to maintain nutrient consistency across large-scale production.
Daily routine:
- Measure reservoir EC and pH first thing in the morning, before lights turn on or irrigation starts.
- Record readings in a log (spreadsheet, grow journal, or cultivation software). Trends matter more than individual readings.
- Check reservoir volume and top off with pH-adjusted water if EC has risen, or with dilute nutrient solution if EC has dropped.
- Verify that inline dosing systems (if used) are delivering at the correct rate by checking output EC at several delivery points.
- Walk the crop and visually inspect leaf color, tip condition, and growth rate. The plants are the ultimate indicator of whether your EC is correct, regardless of what the meter says.
Weekly routine:
- Perform a full reservoir change. Dump and clean the reservoir, mix a fresh batch, and record the starting EC, pH, and volume.
- Calibrate EC and pH meters using fresh calibration solutions.
- Review the week’s log data. Look for consistent EC drift patterns and adjust starting EC for the new week accordingly.
- Check and clean any inline filters, drippers, or spray nozzles for salt buildup.
- Measure runoff EC and pH from several representative plants to assess root-zone conditions.
Monthly routine:
- Test source water EC and pH to catch seasonal shifts in municipal or well water quality.
- Inspect and clean EC and pH probes. Replace storage solution for pH probes.
- Review the month’s growth data against nutrient logs to identify correlations between EC adjustments and plant responses.
- Evaluate whether nutrient brand, formula, or concentration should be adjusted for upcoming crop stages or seasonal environmental changes.
- Send a water sample and a reservoir sample to a lab for full mineral analysis if you have persistent problems that meter readings alone cannot explain.
The difference between a hobbyist and a professional is not the equipment or the nutrients; it is the consistency of the monitoring routine. A grower who measures and records every day will outperform a grower with better genetics and more expensive nutrients who only checks when problems appear.