Beginner DIY Overflow Box - Help?

[CA11WLK]

Hi everyone, i hope i have posted this in the relevant section.

I'm completely new to the hobby, but following a lot of advice from social media groups on reefing i've managed to successfully st-up my marine tank and sump complete with a Durso drain. Last night when doing a first fill and leak test it dawned on me i have made my overflow box (glass) to low by about 1.5"-2".

Does anybody have any ideas on how i could raise the height of the overflow box without having to remove the already siliconed glass panels?

I was thinking about getting some acrylic and stick that to the glass and add a weir comb on-top but not sure on the best/safest way to bond acrylic to the glass in a way that would keep it waterproof.

Photo below shows my overflow box at present (Please kindly ignore the excess silicone )

Thanks in advance!

 

[Ron Reefman]

First, welcome to Reef2Reef! #Welcome

Congrats on doing your own work.

Adding acrylic to the top of the glass overflow would be difficult. Silicone doesn't stick to acrylic very well at all. You could try something like 3M Co 5200 marine adhesive. But it's white and it might look awful.

You could just make small glass parts to silicone to the outside (or inside) of you existing overflow box that would raise the level to where you want it.

IMHO, figuring weir size and height is quite difficult. The size of the return pump and the amount of flow you want becomes a difficult calculation. I have built tanks and I always end up having to make adjustment to what I started with. Doing that with a glass overflow box and straight edge will be a real trick. Use of a variable speed return pump make make life a bit easier.

Good luck.

 

[CA11WLK]

First, welcome to Reef2Reef! #Welcome

Congrats on doing your own work.

Adding acrylic to the top of the glass overflow would be difficult. Silicone doesn't stick to acrylic very well at all. You could try something like 3M Co 5200 marine adhesive. But it's white and it might look awful.

You could just make small glass parts to silicone to the outside (or inside) of you existing overflow box that would raise the level to where you want it.

IMHO, figuring weir size and height is quite difficult. The size of the return pump and the amount of flow you want becomes a difficult calculation. I have built tanks and I always end up having to make adjustment to what I started with. Doing that with a glass overflow box and straight edge will be a real trick. Use of a variable speed return pump make make life a bit easier.

Good luck.

Thank you for your response!

I originally installed the overflow box in situe making it difficult you get a neat job with all the silicone. I think i might just cut the silicone off and start again but now i know the correct measurements needed i can make the box separately and then silicone it into place.

ive got a nice DC return pump and my flow is highly impressive, although i must admit i did no calculations.

Thanks for the tip on silicone Acrylic/Glass!

 

[Ron Reefman]

I did a few overflow boxes out of acrylic and cut the top in an extremely shallow 'V'. It worked well and also looks very clean. I'm sure you can get glass cut like that as well.

In my new build I drilled holes rather than a weir. Less chance of 'stuff' over topping the weir. BTW, in a 90g tank I'm running the return pump at 900 gph. I also flow tested the overflow before I did the final set up to make sure it would drain 900 gph.

 

[CA11WLK]

Your overflow box and wier looks exactly how i had imagined mine when i set out! that looks so good. i like the double ended return pipes too. i think i might have a look at some Acrylic options in the future.

 

[Ron Reefman]

I ran that tank for several months with just the flow from the return pump. But with more rocks and a changed rockscape, I added a couple of wavemakers.

 

[dbowman5]

i would suggest that the extension does not have to be watertight. if you could make an acrylic weir that you could slip onto the glass with clips or a second layer of acrylic it would work. some water seeping through the seam would not defeat the skimming action at the top and would eventually plug up with debris.

 

[WVNed]

i would suggest that the extension does not have to be watertight. if you could make an acrylic weir that you could slip onto the glass with clips or a second layer of acrylic it would work. some water seeping through the seam would not defeat the skimming action at the top and would eventually plug up with debris.

That will give you a lot of drain down if the power goes out though.

 

[dbowman5]

That will give you a lot of drain down if the power goes out though.

true

 

[CA11WLK]

Thanks for the input guys, i actually removed the overflow box last night and removed all the silicone. Didn't have any larger glass panels lying around to make a taller box, so just made a slight extension. Going to fit it into place tonight, seal it and clean all the excess silicone off.

Hopefully be able to share some photos with you guys.

@dbowman5 - Yeah, i was thinking about it not needing to be water tight, but my sumpy isnt the largest so the drain down in the event of a power outage wouldnt have been good.

Note to self for any future builds, 1. Build a bigger and taller sump, 2. build taller weir and overflow box.

Everyday's a school day!

**EDIT**

This is what the current modification looks like for anyone who may be in a similar position.