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pH, EC & Water Quality Management

pH and EC problems are behind more hydroponic issues than any single nutrient deficiency, mostly because they're invisible until symptoms show up on the plant. These guides cover why pH drifts, what EC to run at each growth stage, how Australian tap water varies by city, and how to actually tell whether your meter or your reservoir is the real problem.

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How to Clean Biofilm From Hydroponic Lines Without Damaging Roots
Quick Answer: Cleaning Biofilm From Hydroponic Lines Biofilm is attached microbial and organic material that builds up inside wet plumbing, not something floating loose in the reservoir. Signs of buildup include uneven flow between outlets, gradually declining flow, a slippery internal residue, and an off smell from tubing or fittings. Isolate the affected plumbing section rather than running strong chemicals through lines that are still connected to living roots. Start with plain water, disassembly and physical cleaning before considering anything stronger. Never let concentrated chlorine, strong acids, strong alkalis, concentrated... Read more...
Why Is My Hydroponic Reservoir Turning Green? Preventing Algae and Light Leaks
Quick Answer: Why Is My Hydroponic Reservoir Turning Green? Green water almost always means algae, and algae needs light reaching the nutrient solution to establish, not just moisture and nutrients which are already present in every reservoir. Common light leak points: lid edges that don't seal flush, net pot gaps, clear or translucent tubing, sight tubes, and light-coloured or clear reservoir walls. Even a small illuminated wet patch is enough for algae to establish and spread from. Algae competes with roots for oxygen and nutrients, and can clog pumps, filters... Read more...
Why Is My pH Meter Giving Inconsistent Readings?
Quick Answer: Why Is My pH Meter Giving Inconsistent Readings? Most inconsistent readings come from a dirty probe, poor calibration, incorrect storage or an ageing sensor, not from the water itself. Rinse the probe with clean water before and after every test, and never scrub the sensing glass. Calibrate using fresh buffer solution in a separate clean container, never inside the original bottle, and discard used solution rather than pouring it back. Always store the probe wet in storage solution between uses. Letting it dry out damages the sensing membrane... Read more...
Hydrogen Peroxide and Hydrochloric Acid in Hydroponics: When to Use Each
Hydrogen peroxide and hydrochloric acid are both used in hydroponic systems, but for very different purposes. This guide explains when to use each, the risks involved, and how to handle them safely in your grow room. Read more...
Understanding pH and EC in Hydroponics: A Practical Guide for Australian Growers
Quick Answer: pH and EC Testing and Control in Hydroponics Australia Target pH range: 5.5 to 6.5 for most hydroponic systems. Outside this range nutrients become unavailable regardless of reservoir concentration. Target EC varies by crop and stage: 0.6 to 1.0 for seedlings, 1.2 to 2.0 for veg, 1.8 to 2.5 for flowering. Calibrate your pH meter at least weekly using fresh calibration solution from sealed sachets, since old solution gives false readings. Always add pH Up or Down in small increments and retest before adding more, since overcorrection is... Read more...
Why Does My pH Keep Dropping?
Quick Answer: Why pH Keeps Dropping in Hydroponics A drop of 0.2 to 0.3 per 24 hours is normal plant feeding activity, expected and manageable. A drop of 0.5 or more per day points to a specific problem that needs fixing at the source, not just correcting. Fast-growing plants in peak veg release hydrogen ions as they absorb calcium and magnesium, which is completely normal. Microbial activity from organic additives and root inoculants produces organic acids that drop pH aggressively. Algae in reservoirs exposed to light drives large, rapid pH... Read more...
What EC Should I Run?
Quick Answer: What EC Should I Run EC measures nutrient solution strength in mS/cm, with higher EC meaning more dissolved nutrients. Seedlings and clones: 0.6 to 1.0 mS/cm. Vegetative: 1.2 to 2.0. Flowering: 1.8 to 2.5. Final flush: 0.0 to 0.5. Australian tap water already carries an EC of 0.1 to 0.6 depending on your city, so subtract this from your target before adding nutrients. Overfeeding does not give plants more, since above the tolerance threshold it creates osmotic stress that blocks uptake entirely. Check EC daily in hot weather,... Read more...
Australian Tap Water for Hydroponics
Quick Answer: Australian Tap Water for Hydroponics Three parameters matter: starting pH (usually 7.0 to 8.5 in Australia), EC or mineral hardness, and chloramine treatment. Melbourne and Sydney: soft water, EC 0.1 to 0.15 mS/cm, pH 6.8 to 7.5, a clean baseline but may need Cal-Mag supplementation. Brisbane: moderate hardness, EC 0.2 to 0.3, pH 7.0 to 7.8, generally a good baseline for hydroponics. Perth: highly variable by suburb, EC 0.2 to 0.6, pH 7.5 to 8.5, bore water suburbs must test their specific supply. Adelaide: hard water, EC 0.3... Read more...