Plumbing, why closed loop

[centrek]

I've got a 75g that is not drilled. I'm looking to keep a lot of SPS and a couple clams. I'll have some others i'm sure, softies and LPS, but the majority would be the SPS.
I'm toying with the idea of taking my tank to a glass shop and having them put a couple holes in the back of the tank, since i hear that it isn't tempered anywhere, except on the bottom piece of glass.
I don't like the overflow box with the siphon that I have right now, so i'd like to do away with that. What kind of flow could I get out of the tank if I had a 1" bulkhead for the overflow down to the sump?

If i did have them drill it, where should I get the holes drilled and how many do you think i would need? I've got a room behind the wall that my tank is going to be on that is dedicated to sump and fuge and the like. Would i want to drill the tank in the back bottom corner and silicone an acrylic overflow around it? Or would I want to have the hole cut near the surface of the water and just put a strainer on it? I want it to be silent in the display room.

Also, what is the advantage of using a closed-loop rather than just having pipes empty into the sump and then having 2 pumps send water back to the display thank?

Please give me some ideas on where the overflow and return holes should be, how many do you think I should have, and your thoughts on which is better, closed loop or just another pump from the sump. Also tell me the size holes you think i should get.

Thanks all!

 

[wickerj]

I think you'll get better surface skimming with an overflow box. If you use 2 x 1" drains you should be able to move a lot of water through your sump. As long as you've got the space for a large sump you should look at the Rubbermaid stock tanks, they're big enough to handle the large volume of water you plan to run through it without returning micro bubbles to the tank.

Jeff

 

[AvonleaPA]

Also, what is the advantage of using a closed-loop rather than just having pipes empty into the sump and then having 2 pumps send water back to the display thank?
Thanks all!

The advantage is that you don't need to have unsightly powerheads inside your main tank. The closed loop replaces the powerheads used for circulation.

 

[centrek]

yea, i would make some overflows out of acrylic and then have a bulkhead inside that overflow box...it'd be similar to the reef ready systems, except the bulkheads would be in the back of the tank instead of the bottom.
My current overflow has a prefilter sponge, do many of you have those on your overflows? And also, to make it quiet would you suggest a Durso?

I dont know if I really want to make 2 overflows, so I may just make one and have a bigger overflow. What are your thoughts on that? I've got plenty of room for a sump, so i'm not too worried about the size of that.
I will look into a closed loop system though, if I'd need another pump to send the water from the sump, why not just stick it on a closed loop...my sump should have plenty of water movement, right?

 

[conundrum]

I think you misunderstand, closed loop leaves the main tank, goes to a pump and returns to main tank for increased water movement instead of powerheads. Usually enter's and exit over back so as not to reduce the drainback capacity you want going to the sump. This loop can draw/exit low in the tank without any fear of overflow.

use only one pump (of proper size) to return sump water back to main tank.
I thought all the glass was tempered priar to assembly. If you drill high, get large holes, mine are dual 2 5/8 high in back corners. I can get 900 gph even with one plugged as a safeguard in my 110 tall. I run a 25 gal sump and it is plenty large. I also run a 1100 gph closed loop in main tank for flow. set on a random timer.
It is safer to drill high, use rubber elbo on outside to prevent strain on back glass from exit pipe movement.