Water & Irrigation — AutoPot

This page belongs with AutoPot's watering systems, which run on gravity and use no pump. That makes the tank part of the system rather than an accessory: capacity decides how long it runs, and height decides whether it runs at all.

Two kinds of tank

The FlexiTanks fold and run from 25 to 750 litres. They pack flat when empty, which helps if you want the space back out of season or need to move the tank. The rigid 47 litre tank is the solid option, with its own stand to put it at height.

Capacity is days, not litres

The useful sum is not how many litres go in but how many days that covers. It depends on plant count, plant size and room temperature, and it changes through the cycle: the same fill that lasts a week in week two empties in two days in flower. Size on the heaviest period rather than the average, especially if the tank has to cover a time you are away.

Height is not a detail

Because there is no pump in the system, the tank must stand higher than the trays. About thirty centimetres of rise is enough in practice; much higher puts excess pressure on the float valve. The stand for the 47 litre tank exists for this. With a FlexiTank you arrange that height yourself, and bear in mind that a filled 400 litre tank is a serious weight that needs something solid under it.

Frequently asked questions

Which size suits my system?
Work out what your plants take per day in the heaviest week and multiply by the days you want to cover.

Can a FlexiTank stand outside?
Algae grow on light, so keep the tank dark and closed. Frost is the other reason to think about it in winter.

Where are the systems themselves?
Under Growing Systems, on this brand's own page.