Fish Tank & Sump Tanks
A “sump” is an area where run-off water accumulates. In an Aquaponics System, sump tank is generally placed at a lower point than the grow beds. The grow beds drain via gravity or by siphon action into sump tanks. “CHOP”, “CHOP2” (Constant Height One Pump) and CHIFTPIST (Constant Height In Fish Tank Pump In Sump Tank) designs employ a sump tank in order to both maintain a constant height in the fish tank and also to add more water volume to the system, thus creating more system stability with regard to pH and temperature.
The volume of sump tank should be such that it can handle the water volume when all of your grow beds are full at once. In Raft Beds the sump tank size should be such that it can handle the water displaced by pump into the raft system. But in case of media/siphon based system you need to subtract the water displacement volume due to the effect of the grow media (for Hydroton its around 55% and with 3/4″ gravel/bajri its 62%).
In Hydroponics Systems sump is called nutrient mix tank and water is being circulated into the system using pumps, similar to Aquaponics Systems.
PLEASE NOTE – WHILE USING SUBMERSIBLE WATER PUMPS THE VOLUME IN SUMP TANK SHOULD BE SUCH THAT PUMP IS SUBMERGED IN WATER ALL TIME DURING OPERATION.