If you had to make an overflow box

[ctreptow]

Hi All

 

I am getting ready to drill the back of my 75G tank to install an overflow box. I currently use CPR over the top overflows. I wanted to know others opinions on how to create the best siient overflow in a drilled tank. I am going to install 2 1" drains. I am thinking drill in the center of the tank about 3 inches fron the top. I can run an overflow box across the whole back and feed it into the drains or I can just build a box around the drain holes to create a much smaller overflow box.

 

Chris

[ErikS]

I'd do it across the entire back - more sufrace skimming = better.

[dandy7200]

Heres what I did for my 75.

 

1/4" glass corner overflow 8"x6" with holes for 3 ea 3/4" bulkheads. Then 1/4" black acrylic is added. With the back painted it somewhat disappears. I drilled a bit differant. Bottom hole is main drain that is restricted with a gate valve, middle hole is emergency overflow standpipe, third top is return.

 

 

 

 

 

Heres the external on my 54.

 

 

 

Both skim the surface very well turning 10x the tank volume through the sump.

[Rascal]

I installed a Calfo style horizontal overflow on my recently set up 150G from Glasscages. Erik is right -- all the way across the back will give you more surface skimming, but I went with only 24" across the back, 4" wide, and 6" deep. My tank is viewable from the front and right side, so the overflow is in the back left corner. I was willing to sacrifice some surface skimming for more in tank real estate. I have 3 x 1" drains through the back of the tank, I think about 3 inches down from the top. The top of the overflow box is about 3/4" from the lip of the tank (which is 1/2" thick), which puts my water level about an inch from the the top of the tank. I used slip-slip bulkheads. Outside of each bulkhead is a T fitting with a short section of pipe coming up which is topped by a cap. The caps have a 1/4" hole in them with airline tubing inserted with a silencer valve. I have experimented with various fittings inside the tank, but finally settled on this: The outside two drains have a T fitting, the top of which is open and the bottom of which has a strainer. The middle drain just has an elbow to a strainer. I have the flow adjusted so that the strainers are submerged (so no "sucking sound) and the water drops about 1 1/2 inches from the overflow. I opened the strainers up a bit with a drill, but when/if they get clogged anyway, the water level will rise until it hits the open tops of the two T fittings. This is my safety back-up. In theory, water will continue to drain through the unimpeded tops of the T fittings, while the loud "sucking" sound alerts me to the need to clean out the strainers.

 

Now for the lessons learned part:

 

1st and foremost -- use bigger drains. This will give you much more of a safety factor and will help in noise reduction. If you look at the designs for the Durso & Stockman standpipes, both involve an initial drain through a larger diameter pipe which then necks down to a smaller diameter after a short distance. I don't know why, but this seems to really make a difference in the noise department. I had this design on my old system's standpipe and I never heard the water going down the pipe. In my current system I get the noise from the overflow which isn't too bad but I also get the noise of the water going through the pipe. I think larger diameter pipes would just be quiter overall. If I had to do it all over again, I would use 1.5 at least, maybe even 2".

 

Make sure the overflow is perfectly level. If not, the massive waterfall on the lower side will never let you forget it. Thankfully, this is one part that I did not screw up.

 

Use a lip at the bottom of the overflow. You can use this to place frags of some sort of encrusting coral -- zoas, gsp etc. . . . Or you can just wait for the coraline to grow.

 

Here's a pick of my tank just after i set it up so you can get the general idea. I am hoping the whole thing will become invisible behind massive sps growth eventually , but first I have to deal with the massive HA I am experiencing currently. :(

 

Sorry for the long post, but hopefully there's something in there helps.

[ctreptow]

Thanks Guys

 

Great ideas and the pics are awesome..

 

Chris

[ErikS]

I should have mentioned that - I agree with oversize. I flow about 700gph through the overflow & use a 1.5" drain = nothing gets stuck. Had a few chromis go for a ride too!

 

Big drains handle the flow & can be very quiet. I like an adjustable air Durso/Stockman - very easy to tune for quiet flow.

[Norboo]

If you want to reduce noise, use slip x slip bulkheads. All the slip fittings have larger diameter than the threaded fittings. I

[Rascal]

Also, add a 3

[Norboo]

This sounds like a good idea. Kind of like a water slide instead of a water fall, if I have the idea right. Any pics and/or explanation as to how you did it?

 

I used a router bit (Dremel to fine tune it) to cut acrylic sheet to measurement (made a template to fit the overflow) and 45 degree on one edge that would meet the overflow. I also had to cut out half moon circles to fit the Durso and return pipe. Used weld-on to cement it in place.

 

Sorry no pic as of yet.

Edited November 30, 2006 by Norboo