How to seal overflow hole?

[cheucklate]

Greetings. My reef ready tank has a small design flaw where if power turns off, a few small holes on the overflow will continually drain about 5 gallons of water into the sump. My sump is 10g so my water level is already VERY low to begin with. Any way to seal up the section to decrease water drainage?. electrical tape? glue?..
First picture shows the hole





second picture shows what I want to seal up. Thank you!

[garygonzales]

couldn't you just lift it higher up from the water..mine i can slide up or down...

[cheucklate]

No, I have already experimented multiple combinations of raising and lowering the gate. Water seeps into through holes or creases no matter what. I need to completely waterproof seal a portion.

[KStatefan]

If you seal your overflow as indicated in the second picture, the water level in your DT is going to raise.

[cheucklate]

Yes I am aware of that. It'll raise by a miniscule. however 90% of the water is still going above the teeth which is normal. The problem with my overflow is there are small holes and creases BELOW where the water is suppose to enter the overflow box. So when all pumps and power and turned off. The hole will gradually leak 5 gallons of water into the sump in about 30 minutes. I want to prevent that.

[garygonzales]

im confused when pumps get turned off or power ...the water siphons back into my return head..that fills up my sump..it dosent come from the overflow box...and how high i put my return line determines how much water gets siphoned back into sump...hmmm

[cheucklate]

I'm not talking about siphon.

Imagine you have a overflow box. Now imagine there is a hole in the middle of the box. If all power goes out, for my setup, water will continuously exit through the hole essentially dumping the water into the sump up until where the hole line is. Get it?...

I'm trying to fix the HOLE.

[thegrun]

Cut a piece of black acrylic and glue it onto the overflow with Weld-On #4 or #16. You would need to drain down the tank a couple of inches, but the solvent cures within 15 minutes so I don't see that as an issue. Tape will not work and could release toxins.

[cheucklate]

Thank you for reply thegrun. The overflow is bowed however will that be an issue for a leak tight seal using weld on and flat acrylic?

[Sk8r]

Be careful: that design is trying actually to limit draindown and also protect against overflow. Corner tank? I had one of those 10 gallon sumps on a 50 wedge, and did manage to cope with the draindown, but you certainly can't have a very full sump with that drainage.

[ca1ore]

I don't think it's a design flaw, just that you are expecting it to function in a way that's not realistic. Those adjustable weirs aren't going to ever be completely water tight. None of mine are. Plus sealing the adjustable weir is only going to save you about a 1/2" of drain-down which in a typical 30 gal is about a gallon. I'd suggest either lowering the adjustable weir so that the excess water draining is reduced, or get a bigger sump.

[ericarenee]

Originally Posted by thegrun

Cut a piece of black acrylic and glue it onto the overflow with Weld-On #4 or #16. You would need to drain down the tank a couple of inches, but the solvent cures within 15 minutes so I don't see that as an issue. Tape will not work and could release toxins.

My idea is similar.. Put a piece of tape on the back side and fill the hole with weld on 16.. the thick stuff from tube.. No need to use a extra piece of acrylic... the tape on the back will hold it in the hole until it sets up....

Of Course clean the tape adhesive off .

[stingeragent]

Looks strange. My overflows never get that high up the teeth. You could get a 20 gallon sump for the same price as the materials to fix it.

[LuciDog]

Get a bigger sump. Problem solved.

[figuerres]

I also say get a larger sump, safer, simpler way to deal with it.

[WilRams]

Getting an adequate sump makes more sense then trying to rig this to do what you want which may not even fix your issue.

[hotelbravo]

i would also jump on the band wagon and say get a bigger sump to fix the issue not to fix the hole. the hole isnt even a design flaw it has purpose.

[cheucklate]

Thanks for everyone's response. It looks like general consensus is telling me to get a bigger sump. My DT is a 30g cube (24 x 24 x 12), so a conventional 20g sump would not fit in the stand. I would have to buy a custom sump or DIY. Really an expensive operation to solve 1 hole. I have since applied a large goop of reef safe silicone and it seems to be pretty leak proof. I understand some are saying the hole design has a purpose care to expound more? If it is to prevent DT overflow, wouldn't a even larger sump be more detrimental if the drain pipe ever gets clogged.

I appreciate everyone's concern, if my solution really is more dangerous than I think, I may consider building a sump.. althought I have no experience with it.