Overflow Problem, Help!!!

Tom2257 · Feb 20, 2022

My tank is a 90 Gallon, fish only reef system. The filtration system is a Proclear aquatic system model 125. 2 days ago the tank started overflowing, thankfully I was able to stop the pump before it became a serious flooding issue. The only thing that has changed was addition of hyperactive snails that seem to like the overflow box. My theory is they got between the overflow box and the tank wall and caused the box to loosen and maybe slide down somewhat? My current water level is very near the stop and I fear it could again overflow anytime.
My question is this: How do you determine the safe, correct level to adjust the overflow box? I have enclosed a picture.
Secondly, my sump is always running low and puts tons of air bubbles in tank through main line to the head. I add around 2 quarts of water per day on a minimum, sometimes it needs more. Is this normal? Nothing is in my sump besides the heater and pump.
Any and all advice is appreciated.
Tom

Glenner’sreef · Feb 20, 2022

Hi Tom, Is your overflow drilled or are you running a syphon? Re: your tanks evaporation. I lose 1 gallon a day from evap. An ATO is your answer.

Tom2257 · Feb 21, 2022

Glenner’sreef said:
Hi Tom, Is your overflow drilled or are you running a syphon? Re: your tanks evaporation. I lose 1 gallon a day from evap. An ATO is your answer.

I am running a siphon. The box has slits to allow water flow, should the box be adjusted a certain depth?

Wayofthereef · Feb 21, 2022

Ok so theres a few different things you need to look at. #1 your return pump, is it a variable speed? If so slow it down and find the balance. #2 in some cases your return to the tank is good but your flow to the sump is too slow, so do you have a valve in line that your slowing the flow to make it quieter? If so you might need to open that up. Its all a balancing act. #3 did you make an antisyphon of some kind? Eg dorso or something to make it run quieter because sometimes if made incorrectly will sliw the flow to the sump and overflow the tank. #4 and auto top off is your best friend but can cause problems. It works great making sure you dont add too much water but if the flow back to the sump is too slow and your return pump is emptying the return chamber it will keep filling and eventually overflow the tank. Find the right speed. I have a dc pump and the scary thing is for me is the perfect balance is the absolute slowest it can go. So i have my ATO Sitting right above the pump so it doesn't add too much but even today i was near the tank and heard the ATO go on 3 times in 20 minutes and knew immediately there was an issue because that was way too much. Also getting a controller with a leak detector can be your best friend

Snoopy 67 · Feb 21, 2022

Tom, THE most important thing with a siphon tube overflow is: any air bubbles in the siphon tube must be pulled completely out by the flow.

Super Fly · Feb 21, 2022

sounds like the overflow can't keep up with the pump, i.e. pump is putting too much water back into the display that the overflow drain line can't handle. Like others have said, I'd try to adjust the pump flow amount, if its not adjustable u can always add a gate valve.

Snoopy 67 · Feb 21, 2022

The inside box should be able to go up & down. It also looks to be a small sized box & not able to handle too much flow which would mean overflowing the tank. You will need a valve on the pump if it's not DC & adjustable to slow your flow back to the tank.
As others have said - you need an ATO, auto top off in the pump section of your sump to replace any evaporation.
Try to keep a good amount of water in the inside box so the level does not drop too close to the bottom of the siphon tube.