DIY internal overflow

[frank10]

I'm hoping to drill my tank soon and I want to install an internal overflow box.

The tank is glass, so should the overflow box be made out of glass or can I go with acrylic?

I read somewhere that acrylic attached to glass will eventually leak.

Also, what thicknesses are suitable for glass or acrylic? This is for a 75 gallon glass tank. (48x18x20)

[RobinsonFam1]

about 1/4" will be fine. when you install acrylic baffles in a sump or an overflow box you have equal water pressure on both sides of the acrylic. therefore no real pressure to cause a leak. almost all boxes in tanks are made with acrylic or plastic. make usre you make clean cuts and use aquarium silicone to adhere it. i have not had much luck with other silicones when doing this but i know many who do.

BR

[frank10]

What is a good aquarium silicon to use? do they sell it at local hobby shops?

[Micks]

looking for a reply on whats a good silicone on glass 1/2 inch tank

[Geoff]

i think even HD sells aquarium sealant. i have also seen it at most LFS. it is usually sold in the tube and not in the gun. i believe aquarium sealant is nothing but 100% silly cone. no colouring or anti mold compounds added. it is just an easy way to say pure silly cone.

G~

[Mike O'Brien]

GE II silicone for windows and door's is a popular choice.

[DwightKeenan]

I am going to be doing the same thing for my 75g and I wast told to make a four sided internal overflow box that is hlep in place by the bulk head and the gasket between the box and the glass wall.

I am very interested in what you decide, as I am not 100% sure on the four sided box.

Also, are you adding two? Where are they going, back wall, side wall? How far fromt he corners do you plan on drilling?

[motorslave]

Youre not going to drill the bottom glass are you? Most tank makers use temperd glass on the bottom and it cant be drilled. Just move the bulkhead up toi the side.

Robert

[DwightKeenan]

Originally Posted by motorslave

Youre not going to drill the bottom glass are you? Most tank makers use temperd glass on the bottom and it cant be drilled. Just move the bulkhead up toi the side.

Robert

No, I am not going to do the bottom. My plan is to do the back side at the top of both corners for overflow and maybe two more towards the center for the return water.

I am looking for advice on how far down and over for each hole.

[motorslave]

Ive heard 4 inches, at least, from the edges. With a 75 the glass should be pretty stout. I even followed this rule on my acrylic tank. Of course you want enough room from the water surface for fittings coming off of the bulkhead such as a Durso if you choose to use one. HTH

Robert

[DwightKeenan]

That is the advice I am looking for.

Do you think I should drill for my return flow, or just bring that in over the top? Does it matter if I have four holes across the top of a 75g?

Thanks for the advice and info.

[Geoff]

it is better to bring returns over the top. this way you can use an anti siphon hole at the waters surface to stop flooding. with drilled returns there is a good risk of draining the tank to the return bulkheads.

G~

[DwightKeenan]

Good point, but if I bring the returns to the same height as the overflows, won't that make the potential for draining a moot point?

I am trying to be as clean as possible, but maybe I am worrying too much about something real small.

I am trying to avoid doing something now, that I will want to change later for whatever reason.

[frank10]

Originally Posted by DwightKeenan

Good point, but if I bring the returns to the same height as the overflows, won't that make the potential for draining a moot point?

I am trying to be as clean as possible, but maybe I am worrying too much about something real small.

I am trying to avoid doing something now, that I will want to change later for whatever reason.

I drilled a hole for my return water and used some pipe to exit the overflow.