My guess is that you don't have a high enough flow into your submersible pump, which should be in the bottom of your fish tank. Not all of that water should necessarily go to your grow beds, as some of it can return to the fish tank directly, under pressure, helping to keep your fish tank water circulating as well as feeding your grow beds. Jetting water into your fish tank requires ample pump pressure and a reduced pipe size allowing for a high velocity of pump water to be squirted into the tank at about a 45 degree angle. This will circulate the water and help with aeration, which is especially important if your air pump fails.

As we just learned, it is important to keep the water pump and air pump on separate electrical circuits, and we have the dead fish to prove it. We were gone for the whole day and didn't check the system early in the morning before we left and got back late that night. The circuit breaker had tripped the night before taking down both the air and water pumps. This was a stupid mistake on my part as I had checked the power being used by the pump earlier that afternoon, as I had a request for those numbers. When I plugged the pump back into the extension cord I let it drop beside the fish tank instead of placing it back on the lower shelf of the grow bed. During the next fish feeding some water was splashed on the connection and the breaker tripped. Due to the system monitoring, I have a very good idea when it happened, as the feeder did its thing at 5 PM and at 5:11 PM the control valves were not responding. I need to set some alarms.

After returning home the next night, some 30 hours later, I went into the grow room to make some measurements on a grow light size and found the whole system down and 19 dead fish.

The electrician was here today to put in some wire for the solar we are installing but I diverted him to adding plugs on the other circuit in the room so I could plug in the two pumps separately.

Didn't mean to hijack the thread but it seemed like a good time to share that experience.

Oliver