Hydroponic reservoir maintenance checklist

A routine that takes a few minutes a day.

Most hydroponic problems start in the reservoir: a drifting pH, a too-strong mix, warm water or slime on the roots. A short routine catches them early. Use this as a starting point and adapt it to your system and crop.

Every day or two

• Look at the plants and roots. Roots should be white or cream and smell fresh. Brown, slimy or smelly roots are a warning.
• Check the water level. Top off with plain water when it drops. The top-off calculator shows how much to add and what your ppm will be afterwards.
• Check the water temperature. Cooler water holds more oxygen. Many growers aim for roughly 18 to 22 °C (65 to 72 °F) for leafy crops. Warm water invites algae and root problems.
• Check the air pump in DWC systems: air stones should be bubbling evenly.

Two or three times a week

• Measure EC and pH with calibrated meters. Rising EC usually means plants are drinking more water than nutrient. Falling EC means they are taking up nutrient faster than water. Our EC vs PPM guide explains the numbers.
• Adjust pH in small steps, with a few minutes between and a re-measure. A test dose scales to your reservoir with the pH adjustment calculator.
• Write the readings down. Trends tell you more than a single value.

At every water change

1. Drain the old solution. Where local rules allow, diluted used solution can go on garden beds, but keep it out of natural waterways.
2. Rinse the reservoir and wipe off any film on the walls. Clean air stones and tubing.
3. Refill with fresh water and measure its EC and pH before adding nutrient.
4. Add each nutrient part separately, stirring between, at the dose for the current growth stage. Use the nutrient calculator for the millilitres.
5. Re-measure EC and pH and note the values.

How often to change? Every one to three weeks is common. Plan the dates and total water with the water change schedule calculator.

Warning signs

• Cloudy water, a sour smell or green film: clean the system and change the water now.
• Pale new leaves or leaf-tip burn: check EC and pH before changing anything else.
• Wilting even though the water level is fine: check water temperature and roots.

Estimates only: always follow your nutrient manufacturer's label and check your readings with a calibrated meter.