I'm trying out an experiment, to grow shrimp and tilapia at 5000' elevation in Idaho, using daytime aeration to warm up the ponds, comparing conventional and a novel feeding method, and will post progress and results to a previous thread, http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=424112

I am trying to set up 2 Pondmaster AP-100 air pumps (each of which put out about 5 CFM - instructions don't provide a performance curve - but max water depth listed at 11.5 feet) for 2 immediately adjacent ponds, approx 1/10 acre each (I know, overkill?) I will probably have diffusers at about 8 feet.

My question is this - it lists the tubing size as needing a 3/4" ID - which would fit the size of the barb on the airpump - but given what's out there for sale, it seems like this is on the high range. And, given I'll have a few 50 foot (i.e. short) runs from air pumps to diffusers, it may just be easier to bite the bullet and get 100 feet of 3/4" sinking air tubing. But it looked like other pump/tubing/diffuse packages would use 3/8" sinking tubing with a 1/2" barb?

I'm assuming that, for that volume, I'd want to use a single double-membrane diffuser for each pond?

Thanks for any opinions!

Woody,

It's all about back pressure.....The larger line means less resistance to flow and lower back pressure.

IMO I would go at least 5/8 inch ID if you're pushing 5 CFM thru each line. The 3/4 is even better. I push around 2.5 CFM thru 3/8 inch lines, for slightly further runs than you are thinking, and my pump back pressure is around 14 PSIG, too high really IMO. Ideally, I would want it between 5 and 10 PSIG. At 8 feet depth you will already have a 4 PSIG back pressure just to get to depth. The higher the back pressure, the harder the pump works, the shorter the pump life and the more electricity the pump will consume.
Just my 1 cent...

Good Luck with the project! Sounds interesting so I hope you keep us in the loop!

Bill D.