Drain flow question HELP!

[Ally]

Hi! My boyfriend and I are building our 187 gal reef tank. We are trying to move on with the plumbing and we have many questions!

The tank has 3 holes with 3 slip fit 1" bulkheads.

#1 has the 1 1/4" Durso stand pipe for the drain
#2 is the 1" return
#3 I would like to put another 1" drain in case #1 gets clogged

How should I design a fail safe drain with out interfering with the main Durso? Could I put another Durso?

Any pics would be very helpful.

Another question:

How do we measure the drain flow?? We were told that because of our durso pipe size the flow should be around 320 gph, how did they get to this number???

Thank you for your help!!!!

[Fat Tony]

Use the 2nd 1" as a backup drain (just set it up a tad higher than the other durso's )and bring your return over the back of the tank. I have 2 main drains and 2 back-ups on my tank this way and is the safest and easiest way to do it IME.

A typical 1" drain has a flow potential of around 600 gph in non-siphon setup (vaccum setup). What we typically run is a gravity fed non siphon style drain system in our tanks. The typical recommendation is to run about 2/3rds the capacity of the drain max to be able to effectivly keep it quiet (no gurgling). So in your tank, you could get away with about 800 gph. Although I would only recommend about 400 gph (at the requisite head pressure, say if your tank is 4' tall to the top rim, then 4' would be your head pressure) to insure that your emergency drain is effective at draining all the required waterflow.

[Ally]

Thank you!
How exactly does a Durso standpipe work? What is the difference between Full siphon and my regular Durso??? Does one have a air hole and one is sealed??
Also now we are using bluk heads with slip fitting , should I change them to threaded?

[fchidsey]

A link top what Tony is talking about. I found it helpful this is how my setup is going to be plumbed.
http://www.beananimal.com/projects/s...ow-system.aspx