How to cover bottom (and middle?) overflow intake slits?

[LaneBrain]

Hi everyone!
I think I moved some power heads around, and I’m noticing a brown film start to accumulate on the surface of the water.
Watching the top of my center overflow, not much water from the surface gets pulled in. My guess is a majority gets pulled in from the bottom and middle slits.
So my question is, is there anything I can do to cover up those slits so I can have more of the water come from the surface?
My initial though is get some aquarium safe silicon and smear it over the slits. Any other ideas?

 

[luu78]

I cut a small piece of plastic and start covering several slits on the upper weir, fine tuning the number of slits to cover control your final water level. Once you figure that out, cut only enough plastic to cover that amount of slits so that in the event the plastic piece do come off and get suck back in, it will never block the flow more than you originally intend. No modification required…this is how I raise water level in my AIO frag tank to maximize water volume and usuable tank height.

 

[coralfishreef]

Maybe experiment with an additional powerhead mounted near the top of the water or aimed at the top of the water instead of blocking the middle and bottom overflow slits.

 

[chadfish]

That’s ironic, I’m always trying to tune my power heads to get the heavier detritus up to my top-only overflow. I wish I had some lower intake.

In the past, I’ve used black electric tape to cover portions of the weir slits.

 

[Cooper2]

I used Flex-tape to throttle an overflow and had great luck with it.

This is "Flex-tape" (I'm sure you've seen the ads..lol). It stays in place and you can see the wildlife has no issue with it.

 

[ava420]

I used frag putty to completely close off the bottom slits in my small cube. just make up small balls of it and press it into the slits till they are covered. I did it while the tank was full too...
It’s a bad pic but you can see it down the bottom in the back. Eventually it’ll all be covered over with coralline and other algae..