Maximum Flow Through a 1-1/2" Durso Style Return

[CastAway]

Getting confused on what flow to expect in my new build. I did not want to hijack other threads on the subject, so, I thought I'd just start my own. I have a 1-1/2" sch 80 bulkhead, with a 1-1/2" durso return. It measures 13" from the glass bottom to the midpoint on the tee fitting, where I expect the water level to be. I have an Iwaki MD70, rated at 1500gph (25gpm) at 31'. I referenced Sprung's The Reef Aquarium - Science, Art and Technology, pages 92-93, which indicates that 25gpm will require about 6" of vertical water column above the hole. Do I have too much pump? Will a durso work? Does this data in the book apply to durso's? HELP! :squigglemouth:

 

[kschweer]

http://www.dursostandpipes.com/faq/41-what-flow-rates-are-possible-with-a-durso-standpipe

 

[CastAway]

Very informative. Very interesting. I had considered the siphon effect of a durso, if one throttled the air intake - kind of overdriving it. I've always thought my tank manufacturer could have added about four more slots in my overflow. I suppose there's no way to calculate that easily, before I learn the hard way.

 

[CastAway]

...and thank you very much kschweer!

 

[kschweer]

Not a problem. I'm not too sure on specifics of your system but using a calculator that can be found by googling "drain overflow size calculator", states that for 1500gph you will need 23 linear inches of overflow. So your overflow may limit you. If you need to cut back on flow you can either run your reactors off the same pump (ie; carbon, gfo, biopellets) or you could "T" off of your return plumbing and return some water to your sump.

 

[CastAway]

Hmmm. I'm not sure I understand "linear inches" as it may relate to the teeth, but, measured around the perimeter I have 26.5 inches. The top of the acrylic is 1/8" beneath the top of the glass, so I really hope I do not have to throttle back the main circulation pump too much, if at all. Too many things to worry about. I did include a DT bypass valve, so that I could divert flow completely away from the DT, just circulating through the sump. Although it's just a 1-1/2" ball valve, I do have a means to reduce DT throughput. Geeze, I really hope it'll handle the 1500gph though! (love your albums btw, very nice, what I aspire to)

 

[kschweer]

Linear inches from my understanding is the area that has the teeth. Meaning not the side areas that have no teeth if that makes sense. Not sure why I'm having a hard time trying to write it out. I think you're going to be close with the setup you have. May need to reduce flow from the pump just a little bit which isn't really too big of an issue. Your main pump should not be your primary means of "flow" in the tank it is just to "turn over" the tank meaning out it through the sump/filtration. The majority of your flow should come from power heads.

Thanks for the compliments I was not aware that I had any albums. Probably just a feature I'm not aware of. Best of luck, any more questions jus ask

 

[CastAway]

Eh, I'm probably confusing you with someone else. Thanks again.