Overflow problems

[Deadeye]

Let’s see if you can follow my rambling - on my 125, there are 2 overflows each with the intake for a canister inside.
I frequently run into 2 issues: evaporation bringing the water level down to the point where water stops flowing in and only out (dropping the water level in the overflow). This is pretty easy to fix with top offs.
The second issue is that plants (hornwort and duckweed) will block up the overflow and restrict water flow, again draining the overflows faster than they can fill up.
I know I could pull the plants, but I’d like to keep them for refuge and nitrate reduction.
The easiest fix would be to put the intakes on the outside of the overflows, but then I don’t get any water movement in there and pools of stagnant water would be wonderful…
Is there any way I can keep up water flow if I did that? I don’t think a bubbler/airstone would do much.
I could move all plants into the overflow, but I find that the water doesn’t get nearly as clear when I do (and it’s a pain to move whenever a fish wants to go in and can’t find its way back out).
I also could put more holes lower down on the overflow chamber, but then if one of the bulkheads fail I’ll have around 100 gallons of water on the floor instead of 5-10.
Just me venting while I try to figure out which idea would work best. Any other ideas for a fix would be welcome.
Thanks in advance!

 

[Backfromthedead]

Ive seen some halfassed fixes to these issues. Ive seen some people simply drill a bunch of holes a bit lower than the weir to allow more flow into the box from different places. This could probably be accomplished without draining the tank.

I would probably go with the same thinking, but instead opt to drain the tank, remove the boxes, and use a plunge router or similar tool to lengthen the slots of the overflow weir, then reinstall the box. Since youre working with canisters it wouldnt even affect the water level in your tank, just add more surface area to the weir section. In principle this would make it more difficult to clog with duckweed and lasting longer between topoffs, mitigating but not completely eliminating your problems.

Ive had a funny idea when reading about overflows being clogged with plants, but yet to try anything: a sort of gutterguard or brushguard for your weir. Perhaps there is some sort of plastic, somewhat rigid mesh material that could be installed in a sort of "bubble" around the overflow weir that would catch the majority of the plant particles before they clog the weir. I would think there is something similar for pond filters already out there.

 

[Deadeye]

I do like the idea of extending the holes in the top - at least it’s only water from the top coming in.
The overflows aren’t really removable, they are formed by plastic parts siliconed to the edge (the whole thing was designed with a reef and sump in mind).
Old pic with the bichir photobombing:

Issue now:

Not exactly POTM worthy shots but I think it gets the point aI could just remove the whole thing, but then I’d open up the bulkheads to my fish possibly picking at the silicone around them and causing a leak.

 

[duanes]

Back when I used overflow boxes, I found stretching a length of egg crate across the width of the tank, out a few inches out from the overflow box, and just a short distance below the surface held back most floating plants like duckweed, without changing the depth and rate of inflow to the box.

 

[Backfromthedead]

Ive removed several of those overflows, theyre actually fairly easy to get out. silicone doesnt adhere to plastic incredibly well, razor blade down each seam and itll probably pop out with a little tug.

Perhaps the gutterguard wasnt my idea at all, probably just saw one of duanes posts with that egg crate buffer around the weir. That could be worth a try. It could easily be trimmed to fit around the overflow box, just gotta find some way to fasten it to the overflow. And it looks like you already have the black egg crate.

 

[jjohnwm]

Okay, haven't had my coffee yet so I'm gonna use that as an excuse for my stupidity...this time...

You've got a couple of those internal overflow chambers in your tank, but after the water makes its way into them it is removed by the intake of a couple of canisters? Where are these bulkheads that you are concerned about? Why does a tank like that even need to be drilled? Do the canister intakes connect to bulkheads going through the tank wall rather than just going over the top edge?

Either way, I can't understand what benefit you are getting from the overflow boxes at all. I'd yank 'em out of there. As Backfromthedead stated, they're probably not all that firmly held by silicone and are likely easy to remove.

As for the bulkheads, wherever they are, I don't think you need to worry about failure caused by the fish. Even if your fish pick at silicone, they can only access the bit that is squeezed out all around the bulkhead. The seal is created by the thin layer of gasket material between the bulkhead flange and the tank wall; you don't even need silicone at all if those surfaces are clean and smooth when the bulkhead is installed, if the gasket is new. I admit I'm a belt-and-suspenders kind of guy, so I use a dab of silicone in conjunction with the gasket when working on a plywood tank build, just in case of irregularities in the smooth surface, but on a glass wall even I don't bother.

On the ultra-rare occasions I have had a bulkhead fail, it's always been from overtightening which caused cracking. If you have psycho fish with a neurotic tendency to destroy silicone...well, I'd be more worried about the integrity of the tank itself than about the bulkheads.

 

[Deadeye]

I had gotten the tank used and it came drilled on the bottom, in the shot with the bichir the bulkheads are just underneath the layer of hair algae.
I’m pretty sure it’s more me being neurotic than the fish when it comes to the bulkheads and silicone. I’m imagining grains of sand working their way through and breaking a seal… I know, I’m nuts.

 

[jjohnwm]

I had gotten the tank used and it came drilled on the bottom, in the shot with the bichir the bulkheads are just underneath the layer of hair algae.
I’m pretty sure it’s more me being neurotic than the fish when it comes to the bulkheads and silicone. I’m imagining grains of sand working their way through and breaking a seal… I know, I’m nuts.

Lol, that'll never happen.

I hate bottom-drilled tanks. The first few tanks I built and drilled...some glass, some plywood...I drilled that way, then installed vertical standpipes in the bulkheads that reached up to the desired water level I wanted to maintain. I then slipped a much-larger diameter pipe loosely over the vertical standpipe; the big pipe was swiss-cheesed at the bottom to draw the bulk of water from down there, but I always put one or two holes at the top as well to provide just a wee bit of surface skimming. I was careful to maintain the water level in the sump low enough that it could contain the required amount of excess overflow if the pump was de-energized; it worked like a charm, and I felt sooooo smart...

One day, I had removed the outer large pipe for some maintenance, got side-tracked, and left the room. The tank had a few big-ass fish in it, and one of them must have managed to get into the gap of several inches between the fixed standpipe and the back wall...and must have pushed and squirmed and eventually broke the standpipe at the bottom. The tank was only 24 inches deep, but that allowed quite a bit of leverage to be applied to the standpipe by putting sideways pressure at the top.

300+ gallons of water, right onto the floor...fortunately, my own home and in an unfinished basement...but still, what an unpleasant lesson to learn.

 

[puffers4puffers]

Let’s see if you can follow my rambling - on my 125, there are 2 overflows each with the intake for a canister inside.
I frequently run into 2 issues: evaporation bringing the water level down to the point where water stops flowing in and only out (dropping the water level in the overflow). This is pretty easy to fix with top offs.
The second issue is that plants (hornwort and duckweed) will block up the overflow and restrict water flow, again draining the overflows faster than they can fill up.
I know I could pull the plants, but I’d like to keep them for refuge and nitrate reduction.
The easiest fix would be to put the intakes on the outside of the overflows, but then I don’t get any water movement in there and pools of stagnant water would be wonderful…
Is there any way I can keep up water flow if I did that? I don’t think a bubbler/airstone would do much.
I could move all plants into the overflow, but I find that the water doesn’t get nearly as clear when I do (and it’s a pain to move whenever a fish wants to go in and can’t find its way back out).
I also could put more holes lower down on the overflow chamber, but then if one of the bulkheads fail I’ll have around 100 gallons of water on the floor instead of 5-10.
Just me venting while I try to figure out which idea would work best. Any other ideas for a fix would be welcome.
Thanks in advance!

Yes, increase the flow into the overflow area with added holes
or use an auto top off for the evaporation
and just get rid of the plants or create a better barrier to prevent the plant from getting in the way
just a thought…

 

[puffers4puffers]

Deadeye
If I may ask...
Why not use the overflow with a sump?