Pond Boss Forums AERATION Systems questions Airstone question...

Thanks for the advice on putting it in the pond guys and for all the other help. More questions, of course:

I've checked around for both check valves and pressure relief valves but have no idea what I need. I see everything from brass check valves to little plastic ones and pressure relief valves that pop off or are adjustable.

A quick search of "check valve" on HomeDepot.com brought up some valves but I don't have a clue what I need. I also found a brass one w/ a cracking pressure of .3PSI and I quote "Type 304 stainless steel spring, and your choice of Buna-N or Viton seats". Is this what I should be looking for?

You want a pressure relief valve that is adjustable; most common 3/8" threaded fitting. I usu set the blow off abt 6 to 8 psi higher than the required head pressure where the diffuser is sitting. Example: if diffuser is at 14 ft deep, psi head pressure will be 7psi providing the bubbler and hose do not create extra psi gain. So the p relief is set for full blow off at 13 to 15 psi. Since your pump can do 30 psi; 20 psi blow off is also okay. A pressure guage really makes setting the p relief easier & more accurate. If you have trouble finding a p relief I can send you one ($18 + postage).

Chk valve. I prefer plastic vs brass. At local stores you will find them only with springs. SS spring is best, 0.3 psi cracking pressure is great. Buna rubber seal is standard, and viton is for harsh chemical resistance and may? last a little longer; 7-8 yrs vs 10-14 yrs. All my valves are plastic, 3/4" NPT pipe threads & have Buna rubber seals, no springs; some have been in service 8-9 yrs; a Brady product. Retail $6-$8

Questions???

I am such a sucker...

Found a rotary vane pump on e-bay that is only slightly used in a medical setting. It has 1.5CFM (double what my other one had) and up to 10PSI and I picked it up for $49 including shipping. They retail around $300 new. I'm hoping to be able to put this one in my basement and sell the other one. If someone here wanted it I could let it go for the $55 I paid for it plus shipping, it hasn't been hooked up yet. Otherwise I'm going to get an airstone and tubing and sell it as a kit on e-bay.

Anyways, Gast has a recommended Relief Valve for the pump I got. Is that the one I should go with, or would an adjustable one be better? I know nothing about the Gast relief valve except that it costs $14 from a medical supply place.

Bill, would the check valve you have work well with my tubing, or would I need adaptors or something? Also would it work with this low PSI pump?

What A Guy Won't Do For Some Ducks!

Depending on how old the 1.5 cfm rotary pump is it may or may not be noisy. About 5-7yrs ago GAST added a quiet running "head" on many of their rotary pumps. Your pump will have 1/4" NPT threaded inlet and outlet ports.

All GAST pressure relief valves assoc. w/ rotary pumps that I know about are adjustable. Most have 3/8" NPT thread fitting. My check valve comes with a pipe adaptor for 1/2" blk poly pipe. I use it exclusively on our GAST rotary vane pumps. 10 psi is pretty standard max presure for most all rotary compressors. Special models go to 15psi.

Twice the air flow should give you twice as many bubbles and maybe? twice a larger open hole in the ice. That is assuming the 'diffuser' is the same for each.

Of course I have another question. Will they ever end?

I have seen numerous places where it stated to place the airstone only a couple feet under the surface of the water if you want to keep it from freezing. Is this so the bubbles are in a concentrated area so it is more turbulent there? Is there any validity to this?

Thanks again for all the help. I'm still waiting to get my "new" pump.

Opinion. Placing the airstone 2 to 3 ft under the surface will not provide as big of an ice free area as placing the stone deeper in the water. Deeper the stone placement the larger the ice free area will be. BUT, when the stone is only 2 to 3 ft below the surface the deep water near the bottom remains undisturbed and better for the fish because the deep warm water zone close to the pond bottom is undisturbed (depending on max depth) and the fish have a winter "warm water refuge". A fairly large ice free area will allow light penetration and oxygen production from microalgae photosynthesis during snow cover. Air stone action will help distribute the dissolved oxygen.