Pond Boss Forums AERATION Systems questions compare the two

I am reading and learning, and I've a question on pumps.

Why would you chose a 1/4 hp rotary vane over a 1/3 hp piston pump?

It seems the output is close to the same, and with the piston, maybe you could also paint with it etc.. ??

Isn't the piston pump less maintenance?

I'm just wanting some thoughts, since I see alot of folks go with the 1/4hp rotary vane.


One last question,
Do you guys think it's best to oversize the pump in case you don't want to run 24/7?

Welcome dragonslayr!!!

Piston pumps usually offer higher PSI ratings where rotary vanes provide higher CFM, but rarely more than 10 PSI. The choice is usually based on what water depth air needs to be pumped (system working PSI) and the air volume needed.

Oh snap what did you just say rainman???

I can see that it is time to revisit our "When to say OH SNAP" lesson....

Make JHAP say "Oh Snap!"

Thanks for the welcome!
I fear I did not make myself clear.
Let's say you have a 1/3 acre pond, 7' deep.

A 1/4hp piston might do it 24/7.
However, if you upsize to a 1/3 hp piston, could you not run it less often, say 6 hours a night? Hmm, good reason to upsize..


Then we say, hey, you could use a rotary vane 1/4hp instead.
But, you say, yeah, well, they take more maintanence, plus I can blow up ballons, paint, and blow up my girlfriends skirt with the 1/3 piston.

Soo, now, if you will, argue for the 1/4hp rotary..

Shame on you Coreyhap,

Did you or did you not research your new aeration system before purchasing and installing it? Remember, you are under oath here. We do allow concessions to those poor souls such as yourself that have been victimized by the false beauty of the evil GSF, but using the "Oh Snap" quote of your evil leader, for whom I renamed you, is simply unforgivable! As punishment, you are not allowed to read the clarification.

I'm basing my answers/opinions on the assumption you are planning to use a bottom diffused aeration system (membrane diffusers are by far the most efficient)

Roc'R by Gast and Wob'L by Thompson are the 2 most popular piston air pumps available. These generally produce ~3.5 to ~4.5 CFM (cubic feet per minute) of air in the 1/3 HP size. The maximum pressure for these type pumps can be in excess of 100psi, but is generally ~30psi. This type of compressor is usually a better choice if air is pumped more than a few feet deep.

Rotary Vane compessors can produce much more CFM with less horse power, but can rarely produce pressure in excess of 10psi. This type pump is excellent for shallower water conditions.

Both pumps cost nearly the same to maintain when used and serviced properly.

There are exceptions here and I am speaking in VERY general terms. One more point to make is that a rotary vane compressor that is forced to operate near it's max pressure will have lower CFM and a higher maintenance cost to replace worn vanes than a piston pump pushed near the same limits. Be sure to check the CFM to pressure curves for any pump before purchasing.

One other question asked was if "oversizing" a pump is better. Generally speaking again, no, it is not better. You can produce too much turbulance or damage your diffusers with too much air flow.

To answer the 24/7 or less runtime question goes back to the answer above of creating too much turbulance or diffuser damage. Match the pump to the diffusers to produce the proper pond turnover rates (total water volume of the pond lifted) based on a 24 hour runtime. IIRC you want around 1.5-2 turnovers per day

Oh man yeah I know all about that stuff now. I just had a brain cramp is all!! Your second post now that's good stuff.

Rainman,

You have answer my questions very well!
Thank You

I didn't realize the "too much turbulance" thing.

I guess your saying my test setup probably is a bit turbulant.
My 6.5 HP 60gal compressor.. Make quite a bit of turbulance at 90psi.., with a 25' soaker hose..

Not such a big deal since, for the first time in 20 years, all my fish that we feed every night died last week. My wife cried.

Sooo, I'm looking to fix the problem.. Thanks for the help!

Any ideas why they died? What species and how many?

It's been really hot in oklahoma, no rain for a long while. Not much wind..
I was out of town the day before, woke up the next day and all the fish were dead. A few years back, we had not had much luck with bass, so we loaded up with catfish.
Dunn's fish farm said calls were coming in left and right..

As far as I can tell, the all died. Cept the tadpoles and really small minnows.
Though I haven't fished or saned it.
2 giant grass carp
about 25 large catfish
A few small bass
brim