Overflow level up and down and up and down (plus gurgling)

[luckycat]

I have a 90g AGA w/Megaflow and the accessory kit, which includes what I think is pretty much a durso standpipe... with a sump in the basement, about a 7' drop, and a Mag18 returning water back up, split from 1.5" into two 3/4" returns (one the "stock" return, the other PVC).

Fortunately nothing in my diy sump is leaking, and water successfully goes down and back up.

Problem is the water in the overflow goes down, then rises, goes down, rises, etc., with gurgling sounds occasionally.

Is this due to height of the standpipe? I can't imagine it is an issue with my pump return speed, if it were too strong I would think I'd be overflowing the tank, right? It is not clear to me how high the standpipe should be.

Any advice? I have searched the forum for rising/lowering overflow but couldn't find anything specific to the AGA megaflow w/kit.

 

[EJS4]

Sounds like the vent hole at the top of your standpipe is not large enough or clogged. Read the description in the build your own section on www.dursostandpipes.com/

 

[Phyl]

How deep into your sump are you going? You could have some back pressure from the water you're going into that is causing the gurgling effect. We have that problem with our QT tank. We didn't have the problem when it was dropping straight into a 10g tank underneath but when we moved the overflow to the garbage can next to the tank the longer hose, the curve it it and the fact that the outlet is near the bottom of the can has it build up then gurgle, then build up and then gurgle. We stuffed a piece of filter floss in our overflow to quiet it down. I wouldn't advise that though because it occassionally backs up. Luckily we have a float switch on the system that has prevented many a spill! LOL!

 

[luckycat]

The overflow is on a AGA 90g, so it's 24" tall, and the drain drops down to a sump in the basement about 7' or so. I tried adjusting the height of the standpipe, but no real success...thought I had a good level, and I can definately improve the up & down & gurgle cycle, but can't seem to get rid of it. Others have suggested drilling a larger air hole in the top.

 

[ellisz]

Mine started doing the same thing when I added the basement sump and the bigger pump. I have noticed that as the algae grows in my internal overflow, the surging and gurgle slows down. Since my last tank move, I have been seeing a bit of an algae bloom.

There are many threads on RC about this and most seem to try different style overflows or try different back pressure solutions. I have not got around to messing with mine...