Warm water holds less oxygen, and in a system where the roots hang permanently in it that is exactly where things go wrong. The oxygen level drops at the moment the roots need it most, and warm, oxygen-poor water is also the condition in which root problems develop fastest.
The heat comes from your own room
A reservoir does not climb because of the weather alone. Your lamp warms the room, your pump puts its own heat into the water, and a tank standing indoors follows the room temperature a few hours behind. In summer that means a reservoir creeping up every afternoon and not falling far enough overnight, and interrupting that accumulation is what a chiller is for.
Three capacities
The Tecoponic HY150 cools volumes up to 150 litres, the HY500 up to 500 and the HY1000 up to 1000. Choose on your system's volume rather than on what just squeezes under: a chiller too small for the volume runs continuously and still misses the temperature, and then you are paying for a result you do not get. On a recirculating system count the whole circuit, so the reservoir plus whatever stands in the buckets and the lines.
Who this is not for
Growing in soil or coco and watering by hand, this is unnecessary. Your water stands briefly in a tank and comes up to room temperature on its own, which is exactly right. A chiller belongs with DWC and the other systems where the same solution circulates day and night. If your water gets too cold instead, that is the opposite problem and the Barrel Heaters sit beside it.
Frequently asked questions
At what temperature does it become a problem?
There is no sharp line, but the oxygen level drops noticeably as the water warms and above twenty degrees it does so faster. More important than the exact figure is that it does not swing ten degrees every day.
Can I not just put ice in the tank?
That works for an hour and then disturbs more than it solves: you get a swing instead of a stable value, and with ice made from tap water you are adding something as well. A chiller holds a line.
How do I know whether I need one?
Measure the water itself rather than the room, several days running, at the warmest point of the day. Without that measurement you are buying on instinct, and room temperature tells you less than you would think.
