I have a 300 G2 that I upgraded to last summer, only a few fish came over from the previous tank and I am past the learning curve part of owning a tank with a sump. I had it running quiet and consistent until recently I ordered more fish. Now, for some reason that I cannot figure out, the flow requirements to keep the overflow silent vary from high to low, sometimes very rapidly and I need help figuring out why. (without touching the gate valve)
Further background... This is a freshwater tank, running Neptune Pro and COR20 pump. I have a 1" flowmeter in the return line feeding into a CO2 reactor and then back to the tank. There are also high and low optical sensors in the overflow box that control a program on the neptune to turn the pump up or down to keep it silent. This program is working perfectly and until I added the new fish it would adjust a percent or two up/down to keep the perfect level in the overflow (around 55% on the COR20). Now it can ramp from 35% to 85% to keep that level. (see graph)
Further background... This is a freshwater tank, running Neptune Pro and COR20 pump. I have a 1" flowmeter in the return line feeding into a CO2 reactor and then back to the tank. There are also high and low optical sensors in the overflow box that control a program on the neptune to turn the pump up or down to keep it silent. This program is working perfectly and until I added the new fish it would adjust a percent or two up/down to keep the perfect level in the overflow (around 55% on the COR20). Now it can ramp from 35% to 85% to keep that level. (see graph)