A reservoir is the container that stores the solution used to water or feed plants. In recirculating systems, solution returns to it after passing the roots; in drain-to-waste it is a fresh-mix tank. It is the control point for the system: pH, EC, temperature, dissolved oxygen and the microbial state of the solution are all managed here.
In practice
Bigger is more stable: a large volume changes pH, EC and temperature more slowly. A common home guide is several litres of reservoir per plant, with recirculating systems sized so that a day's uptake is a small fraction of volumebeing reviewed. Keep it lightproof to prevent algae, covered to keep debris and pests out, cool (about 18-21 °C, 64-70 °F) and well mixed. Log readings daily, top up as the level drops, and change or refresh it every one to two weeks in recirculating systems.
Don't confuse with
- Control bucket: the mixing and adjustment bucket in RDWC; part of the reservoir function.
- Stock tank: concentrate tank for injectors, not the working solution.
A recirculating (closed) system returns drained nutrient solution to the reservoir to be reused, saving water and nutrients but needing more monitoring and sanitation.Drain-to-waste fertigation feeds each plant fresh nutrient solution and lets the runoff leave the system rather than returning it to the reservoir.pH measures how acidic or alkaline a solution is on a 0–14 scale; in growing it controls nutrient uptake, with soil best near 6.0–7.0 and hydro 5.5–6.5.EC (electrical conductivity) measures how well a solution conducts electricity, a proxy for total dissolved salts; growers read it in mS/cm to gauge nutrient strength.RDWC (recirculating deep water culture) links several aerated buckets to a central control reservoir, pumping solution through all of them to keep conditions uniform.A stock solution is a concentrated nutrient mix, often 100x or 200x final strength, diluted into the reservoir; calcium and sulfate/phosphate stocks must stay separate.A chiller is a refrigeration unit that cools hydroponic nutrient solution, keeping it around 18-21 °C so it holds more oxygen and root pathogens are discouraged.Dissolved oxygen (DO) is the amount of oxygen gas held in water or nutrient solution, measured in mg/L, and roots need it to respire and take up nutrients.A beneficial-microbe reservoir deliberately inoculates hydroponic solution with helpful bacteria and fungi so they occupy the root zone before pathogens can; GenetixBay prefers this approach.A sterile reservoir keeps hydroponic solution as free of microbes as possible with oxidising sanitisers or UV, a valid strategy that only works if applied consistently.
