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View Full Version : Glass-holes sizing question for new tank


vanisher
06/28/2011, 11:15 PM
I'm getting a new tank built by reef-savvy and I'm debating on the overflow size.

I want lots of surface skimming and was thinking the 1500 overflow, but am concerned it may be too much overturn. Was planning to split the returns (1 on each side of the overflow)

So what does everyone think?

700 or 1500?

Tank specs for reference:
40 gal cube + 20 high sump
I will have a mp10 as only powerhead
w/ swc 120 or 160 skimmer

Thanks in advance! :beer:

P.S. open to other overflow suggestions.

125mph
06/29/2011, 12:14 AM
700...

My 120g will be set up with the 1500.

tdwright1971
06/29/2011, 04:08 AM
agreed 700 should be plenty.

Dan49
06/29/2011, 04:59 AM
I have a 40 gallon with a 700 ,I have two 1/2 " returns, if I had it to do over I'd go 3/4" returns .

jcw
06/29/2011, 06:30 AM
Turnover depends on the return pump, though, right? Not the size of the durso pipes.

obaptista
06/29/2011, 07:42 AM
My current display tank is a 25 gal rimless and I chose the 700 and 3/4 return. The system total volume is 60 gallons plumbed with 2 1/2 pipe. I can really move water through the tank. I've been very happy with the choice. The primary reason I chose the 700 is because I wanted a fail-safe. The best solution is two overflows and two pumps. In a 25 cube, not really possible. So I chose the larger diameter pipe. The problem I am preventing is a fish or snail slowing the overflow enough to cause the return to ...well... overflow the tank. The point to my ramble is, decide on how much turn-over you want, say 10+ min. Then pick an overflow that will handle a little more in case of a partial blockage.

One additional thought. I use one beefy primary pump for return and tee off for feeding reactors. Sometimes I need to throttle or cut-off the reactor so I get more flow in the display. My larger overflow handles it with room to spare. No need to turn off the main pump.

One down side to moving less water over the 700. It is a bit louder.

Hope this helps

Chris27
06/29/2011, 08:27 AM
Why limit yourself to a Glass Holes overflow? All you need is an acrylic box, a hole saw, and a few bulkheads. I've seen a few of the 700 and 1500 models on tanks, and they tend to be very loud.

sjm817
06/29/2011, 10:51 AM
If you are having the tank custom built, why aren't they doing the overflow?

vanisher
06/29/2011, 11:10 AM
If you are having the tank custom built, why aren't they doing the overflow?

They are. I'm choosing which kind.

sjm817
06/29/2011, 11:37 AM
Usually a tank builder will build their own overflows and dont need to use something like a G-H. Is that and option?

vanisher
06/29/2011, 11:45 AM
Usually a tank builder will build their own overflows and dont need to use something like a G-H. Is that and option?

Anything is an option. I was looking at glass-holes because they are pretty universal and it would be easier to get opinions on it.

As I said, suggestions for another type of overflow is more than welcome.

sjm817
06/29/2011, 12:24 PM
Do you prefer a back drilled or bottom drilled overflow? They both have Pros and Cons.

vanisher
06/29/2011, 12:54 PM
Do you prefer a back drilled or bottom drilled overflow? They both have Pros and Cons.

Not sure to be honest, never had a drilled tank.

Only had a CPR overflow on my old 180 and I'm now in a 12 gal aquapod.

sjm817
06/29/2011, 01:06 PM
Bottom:
Takes up more room in tank (top to bottom overflow)
All plumbing is inside the tank, and submerged and inside the stand (quieter)
No visible external plumbing which also allows tank closer to wall

Back:
Smaller overflow which does not go all the way to bottom, less tank space used
External plumbing which is visible, and more audible.
Requires more space behind tank.
More options for overflow size (width).

vanisher
06/30/2011, 08:19 AM
Hmm, I think I will probably go with the glass-holes.com 700 gph with 2 returns.

I'm not too concerned with external plumbing as it will all be out of sight anyway.

JG1
06/30/2011, 09:41 AM
700

kellerexpress
06/30/2011, 10:52 PM
Agreed, the 1500 would be overkill IMO, the 700 will work great. I have one on my 57g and love it. They take a little tuning but I have got mine very quiet. Here's a video of mine so you can hear the noise http://www.youtube.com/watch?v=IR6WQD3c_BU
I'm using 1.5" spaflex into the sump and a single 3/4" return.

vanisher
06/30/2011, 11:43 PM
Agreed, the 1500 would be overkill IMO, the 700 will work great. I have one on my 57g and love it. They take a little tuning but I have got mine very quiet. Here's a video of mine so you can hear the noise http://www.youtube.com/watch?v=IR6WQD3c_BU
I'm using 1.5" spaflex into the sump and a single 3/4" return.

Awesome, sounded pretty quiet. How do you have your return run? I didn't quite see it in the video. What did you do to make it so quiet?

vanisher
07/28/2011, 03:30 PM
Agreed, the 1500 would be overkill IMO, the 700 will work great. I have one on my 57g and love it. They take a little tuning but I have got mine very quiet. Here's a video of mine so you can hear the noise http://www.youtube.com/watch?v=IR6WQD3c_BU
I'm using 1.5" spaflex into the sump and a single 3/4" return.

Do you regret not going double return?

kellerexpress
07/29/2011, 03:48 PM
No the single works great, it's less noise and less plumbing to worry about.

tozzi
07/29/2011, 03:52 PM
700 would b plenty. But since your having a custom tank built, y not get more of a custom overflow? U want alot of surface skimming, let them do a coast to coast overflow

bdare
08/01/2011, 12:42 PM
Do you regret not going double return?

I used a single return and split it with an OM Squirt 2 way... LOVE IT!

krshlln300
08/01/2011, 01:22 PM
I vote the coast to coast overflow, or at least a partial coast to coast overflow. It provides excellent surface skimming and gives you the added bonus of an internal overflow while leaving you plenty of aquascaping room and you can do MUCH more with creating a failsafe mechanism. I use ball valves and emergency drains in my setup and its nearly silent. PM for info if you want.

SoCalBoo
08/01/2011, 08:08 PM
I have had three versions of the glass-holes overflows, including the double 700, and two single 1500.

I have never found them 'quiet'. No matter what I do, they still make a fair amount of noise, but it is not *that* bad and I have heard much worse. If you want very, very quiet, I think something like a bean animal or herbie is your best bet.

As for how many, I really think having a redundancy is crucial. so if you were between, say, 2 700s or 1 1500, I would go with the 2 700s for sure.

If pure skimming efficiency is what you are looking for, then a long, coast to coast is your best bet. The more horizontal skimming surface you have, the more efficient your overflow/skimmer will be. In very abbreviated terms, the solids you want to skim are in the very, very top layer of the water. The more of that water (and the less of the water beneath it) you can skim, the better. You are essentially concentrating the water you want skimmed down to the sump.

OregonReefer
08/01/2011, 11:32 PM
My glass-holes dual 1.5" 1500 doesn't make a sound... the only noise from the tank is the ripple of the surface

ninjazx777
08/02/2011, 05:50 AM
If your having it custom made anyways I would go with a coast to coast external over flow

vanisher
08/02/2011, 07:21 PM
Coast to coast was my original intention, however those pipes sticking all over are kind of an eyesore.

What do you guys think of the 1500 glass-holes overflow and the drain pipes with ball valves to limit the flow?

I really want the surface skimming, but don't want a waterfall flowing next to me.