How many holes should I have drilled?

[DrHank]

I have a 210 gallon tank (96'X24"X 21"tall). I had some problems with the center and one end cross brace coming loose. I decided the best thing to do would be to eurobrace the top of the tank. When I took the top trim off, I found that the glass was not even (had a bevel in it). A local glass shop says that they can fix it for me so I think that is the way I'm going to go.

Since I have to take the tank to their shop, I decided to have them drill it too. Right now it has a large hole drilled in the bottom to accommodate a single 2" bulkhead. I plan on covering it with a 3/8" glass patch. I'd rather have two 1 1/2" bulkheads with strainers for overflows and two 1" bulkheads for returns. I'm thinking of placement at about 2" below the top lip on the back of the tank.

I'm using a MAG 18 for my return pump. I'm also thinking of possibly adding a closed loop system for circulation. Would having additional holes drilled in the back weaken the glass too much? I'm using a Korallia pump #3 in my 110 and it works well. Would I be better off to just have the four holes drilled in the back and use a pair of Korallia pump#4s for circulation?

Your opinions and ideas would be appreciated. This is hopefully, the only time that the tank will be down for repair/modification.

[prow]

you can put as many hole as you want. the bulk heads should brace it enough. personaly i would keep the holes 16" apart to ensure there is enough supporting glass in between the holes. you might want to check with the local glass shop about the thickness of glass in regaurds to drilling towards the bottom of the tank. maybe someone with more glass working savay will chime in.

[AQTCJAK]

If the glass is tempered you are possibly going to have to replace the bottom plate. It is a very trick ordeal drilling a apreviously drilled glass tank. Good luck keep us informed,\.

[mps9506]

How much additional circulation do you want?
For that long of a tank I would probably recommend 4-6 holes for outlets and two hole for intakes.
And like mentioned above, are you sure the glass isn't tempered?

[BigAl07]

Update?

I'm curious to see what's happening here

[DrHank]

The tank is at the glass shop. They are drilling 4 holes and cutting the glass for the eurobracing. I hope to have it back in a week or so but they are kind of fitting it in between their other jobs.

[flricordia]

Just make sure your returns lines are above the point where they won't cause sump overflow incase of power outage.
I would reconcider the euro as the only top bracing. Had it done on a 240 96" and after about a month of holding water the euro started forming cracks in the center front and back. I had to lower water and install a center brace to stop it from cracking any further. 96" is a lot of glass to handle the force of all that water pushing out on it.

[DrHank]

Thanks Mike. The Euro is in addition to 3 cross braces. They pulled loose earlier so I'm going to increase the contact area to spread the force out over the entire rim. I'll be using threaded elbows with strainers on the overflow so that I can adjust the siphon break level and not overflow the sump. You're right, there is a tremendous amount of force. that's what initially caused 2 of my 3 cross braces to let go during a regular water change.

[BigAl07]

sounds like a solid game plan Doc. Cant' wait to see it once it's done.

Allen

[DrHank]

Yea. I can't wait to get it back. By the time I get done with the glass and silicone, there's no way it's going to come apart again (God willing). It will also be the end of the bottom drain and stand pipe. Should work well. The display tank at one of the LFS in Pensacola is set up very similarly. It will be the end of overflows and give me up to 4" of overflow piping if i need it.