Setting up an Overflow

[Apartmenttank]

I bought a 29 gallon tank at petco and am looking at setting up an overflow into my main sump. I plan on making this a Display refugium.

The more stuff i look at the more overwhelmed i become. my tank came reef ready and i missed most of this in building it. So any help or direction would be great.

Things i need to buy:
Reef safe silicone
Overflow box
Bulkheads
Some sort of plumbing
Return pump
Tank stand(if i don't build one)

The things i need to do.
Get the tank drilled.
Glue on the overflow box.
Attach the bulkheads.
Build tank stand(if i don't buy it)

Really having trouble finding the stuff to buy before i start on the todo's i only found a few overpriced overflow boxes on amazon. And bulkheads have a crazy amount of sizes that i don't know which one i will need.

[Mr.Tan]

i recently built an overflow box for my 29g tank using 4 pieces of 1/4" glass i had cut at the local glass place to build a bean animal overflow. I think it ended up costing me maybe $25-30? and that was using a smoked glass and then another $12 for RTV 100 series silicone (once cured its safe to use based on what i've read). You could probably get away with GE silicone I available from lowes/HD that is cheaper than the RTV stuff.

ebay has some decent overflows for cheap, but theyre all acrylic. Glass Holes is always another option too

as for BH sizing, you need to figure out what size piping you are going with (or figure out the GPH flow you will have then type it into the calculator on the main RC page and it will tell you the recommended pipe size.

[jml1149]

[QUOTE=Mr.Tan;24071058]i recently built an overflow box for my 29g tank using 4 pieces of 1/4" glass i had cut at the local glass place to build a bean animal overflow. QUOTE]

Do you have a picture? Would be great, thanks! Trying to do something similar myself.

[Apartmenttank]

That would be a simple solution. You said the RTV 100 series silicone is safe when dried? has it been working well for you for a while? it is unnerving using any silicone.

[toothybugs]

Originally Posted by Apartmenttank

it is unnerving using any silicone.

The RTV silicones are good.

Using silicone isn't hard, it's just different - gooey as all get-out and doesn't wash off so you have to be careful with it. A little practice though and it's no problem.

If it helps, I'm in the same spot with my 40 - I'm doing a 75 setup and will be turning my current 40B in to a refugium over the winter. Doing a Calfo overflow and a Bean out the back.

[Mr.Tan]

Originally Posted by jml1149

Do you have a picture? Would be great, thanks! Trying to do something similar myself.

i'll take some and PM them to you tonight.

Originally Posted by Apartmenttank

That would be a simple solution. You said the RTV 100 series silicone is safe when dried? has it been working well for you for a while? it is unnerving using any silicone.

it is. I did a lot of reading and 99% of people recommended it. GE silicone I is also safe and can be bought from lowes or HD, i just went with RTV for extra strength for my overflow. I bought the tube and used a caulking gun, makes it TONS easier to use, however it is messy still. I wished i taped off along it to make a smooth line....next time i'll do better.

[jimmyj7090]

All silicone is RTV. https://en.wikipedia.org/wiki/RTV_silicone

What people are suggesting is Momentive RTV 100 series. This is structural grade silicone that is effective both as an adhesive and a sealant. G&E type I is just a sealent and no where as strong, but probably fine for installing an overflow box.

[Apartmenttank]

How do you tape along? Is it just a matter of taping two straight lines to remove after like you do when painting?

[jimmyj7090]

Run straight strips of masking tape (use the blue stuff, it's worth the extra $) about 3/8-1/2" out from where you will be making the seams.

-Apply silicone beads along the seams where the overflow will meet the tank.

-Press the overflow into place, silicone will glob out a bit.

-Using a plastic spoon, or finger (wearing rubber gloves) press into the silicone glob and drag along it to smooth it into a nice smooth seam (like the ones you see from the factory). Be prepared to change rubber gloves a few times to keep the mess controllable.

-Peel up the tape while the silicone is still fresh. If you smoothed the seams/globs out right there will be just a hint of silicone touching the tape and it will pull up without making a silicone mess. If there is too much silicone, run your finger or spoon across the seams again, still smoothing it out but now pushing the excess and eventually scooping it out at the top of the seams. The silicone will skin in just a few minutes, don't rush it, but don't take forever either.

The whole operation is easier than I make it sound, just be prepared to change gloves several times, and have a trash barrel or other place to toss the sticky gloves easily. Silicone is super messy to handle, once it's on the gloves, change them. I use a fresh glove for each seam.



Also, since I don't think it's been said already. Silicone does not bond to acrylic with any significant strength (compared to glass). Many an acrylic overflow box has been installed in glass tanks using silicone without issue, but it is a fact that silicone does not have even a fraction of the holding power with acrylic that it does with glass. The best way to put an overflow in a glass tank is to use glass to build the overflow. That said, I've installed many acrylic overflows in glass tanks and never had a failure other than a tank that cracked for unrelated reasons. Proceed at your own risk. (you can also order overflows that install using only the bulkheads and gaskets, no silicone involved, check those out....)