overflow help, please

[helgistef]

Ok, I´m trying to make something out of my 132g empty glass tank and need some help.
how do I know wich linear size my overflow should be if I don´t know what pump I´m going to use, and therefor don´t know how many g/ph it will pump.
The overflow size depends on the g/ph pumped in the tank, doesn´t it?

And the drains and the standpipe( or just any of the plumbing),how do I know the size that´s right for my 132g.

And if my tank is 132g, how thick should the acrylic overflow be, that does matter, right?

that´s it for now.
Thank you

[daytonians]

I think your going about it backwards. First figure out how much flow you want between your tank and your sump. Then calculate everything to fit that, and buy a pump that will work for it.

Most people say to shoot for at least 10X flow. That means for a 132 gallon tank, you would want 132 X 10 which is 1320 GPH (gallons per hour).

I myself prefer to have about double that or 20X. That would give you 2640 gallons per hour.

Use the flow calculators on reef centrals front page to figure out what you need to match your flow needs.

[helgistef]

ok, thank you!

[daytonians]

Feel free to PM me if you have anymore questions.

[Keelay]

<a href=showthread.php?s=&postid=8538120#post8538120 target=_blank>Originally posted</a> by daytonians
I think your going about it backwards. First figure out how much flow you want between your tank and your sump. Then calculate everything to fit that, and buy a pump that will work for it.

I agree figure out what you need in terms of sump flow and to get adequate surface skimming.

Most people say to shoot for at least 10X flow. That means for a 132 gallon tank, you would want 132 X 10 which is 1320 GPH (gallons per hour).

I myself prefer to have about double that or 20X. That would give you 2640 gallons per hour.

Use the flow calculators on reef centrals front page to figure out what you need to match your flow needs.

I agree that you want between 10x and 20x flow in the display. I however strongly recommend not trying to get it using your return pump.

Don't get me wrong you can do it and it will work, but in my opinion there is a better way. Your refugium doesn't need anywhere near that amount of flow. The protein skimmer, if it's not connected directly from the overflow, should get around 2-3x the skimmer's flow rate. (if it is then 1x is fine.) Since the fuge most often has the lower flow requirement than the skimmer, the skimmer drives the overflow flow rate requirement. This is all you need to have for water treatment purposes. 2-3x the skimmers flow rate.

I suggest accomplishing the display tank flow requirements in other ways - closed loop, stream pump, surge device, etc. Why?

1) The return pump is typically 5' lower than the top of your display. that is a lot of head to overcome. Pumping 1000GPH through this pipe will be ALOT less efficient than just pushing the water around the tank. Every month you will see this in your ebill. Compare a:

MAG12 @ 7' head (5' + pipe fittings) = 810GPH using 110Watts
SEIO 820 stream pump (in tank) = 820GPH using 18Watts

2) Drains create bubbles and noise. The more flow you put down them typically makes the problem worse (more noise, more bubbles).
Why create such a challenge for yourself? You can overcome these issues, but at the expense of a sump durso or more bubble traps. All of these taking up your sump real estate which could be used for a bigger refugium or larger skimmer section (you never know when you'll want to upgrade)

[daytonians]

Keelay is right. I have refugiums that are almost as big as my main tank, so I run a lot through them. I know the "experts" don't agree, but I like running 20X through my refugium. It really transports detrius out of the main tank. My setup runs through a refugium full of calurpa, and then into a cryptic refugium, then into my sump where my skimmer is. With power-heads my total flow is about 28X.

There are many people running much less flow off of their main pumps with success. I personally had problems until I increased the flow rates. My calurpa refugium kept growing cyano (red slime), along with other problems.