Pond Boss Forums AERATION Systems questions Sizing a new areation system

Based on my description below, are there any questions or recommendations to my proposed set-up?

I have a 2/3 acre pond. The shape is halfway between a square and rectangle. Depth is almost uniformily 9-10 feet with steep banks on all sides. One of the shorter sides of the rectangle is "only" 6 feet for 20 feet from the bank.

It is a 25-30 year old pond with clear water and some muck about 6-8" deep near the banks.

I don't have any issues with plant growth due to the depth of the pond and watermeal and algae have been easily controlled.

I'm leaning towards a single diffuser like the Airmax PS10. I'm not overly concerned that every corner at every level is fully areated.

My goal for the areation is to support a healthy BG, LMB, and a handful of HSB population. I do have a Texas Hunter feeder and have been using sparingly but will be more aggressive once I start areation.

You may get by with only one diffuser if it can be placed in (nearly) the deepest water, fairly centrally located. In Viginia, you probably don't need to worry about a shallow water diffuser for Winter ice braking (Winterkill avoidance).

Figure out the amount of gallons of water in the pond. Your aeration system needs to bring 1.2-2 times that volume of water to the surface every day. You'll need to find a chart on the diffusers that you are using to see how much water volume they move per hour at "X" cfm of air and make sure that the system is sized accordingly.

Like Scott said above, you need around a 1.2-2 volume turnover per day, but that 1.2 is bare minimum. I like 3-5 times per day on turnover for the best oxygenation and destratification. I love the performance of Airmax, and would suggest a PS20, minimum, for a more angled pond. Improperly installing, or an undersized aertion syastem is often worse than no aeration at all....done wrong, or undersized, you effectively. create a phosphorus pump

Thanks. I'm following the math, but think I'm not applying the right inputs.

Example:
1 Acre pond (43,560 sq ft) with an avg depth of 6 feet is 261,360 cubic feet of water. An Airmax PS20 system is listed as 2.3 CFM. The company rep said the CFM was water moved and not air. A straight calc of moving 261,360 cubic feet at 2.3 CFM says it would take 181 days to move all that water.

What am I doing wrong?

PS: the above is an example on how to do the calc- no need to opine on if it is sized correctly.

I'm just a dumb Aerospace Engineer, not an aeration specialist, but that just seems wrong. A puny little boxer fan moves 20-25 CFM of air, albeit at basically no pressure.

2.3 CFM seems like the amount of air an aeration compressor should pump.

12" of water covering 1 acre of land is 325,851 gallons. 1 acre pond, average 6' deep has approximately 1,955,106 gallons of water......... There are 7.48052 gallons of water in a cubic foot.

Call the company back and talk to someone else. The person you talked to is wrong. The CFM from the compressor is cubic feet per minute of air moved, NOT water since the compressor is not pumping water, plus liquids are usually measured in Gallons per minute or hour...... Use that figure to determine how many diffusers you need. They need to furnish to you a chart like Vertex has to determine how many diffusers you need at the depth that they will be placed. All diffusers don't move the same amount of water, fine bubbles move more water to the surface than coarse bubbles. I have no other information on other brands of diffusers other than Vertex. Here is their information. As you can see, the GPM (Gallons per Minute) moved depends on the depth of the diffuser. These figures are based on 1 CFM to the diffuser at that particular depth.



Also as the diffusers are moved deeper in the water column, the pump has more back pressure to work against. The compressors have a curved pressure/volume curve, showing the more back pressure the less CFM they move. So, a rule of thumb is to size the system for the deepest part of the pond. i.e. if the pond is 10' max depth, and there will be a diffuser there for the summer, then figure 1/2 psi back pressure for every foot of water depth. and throw in another psi for system parasitic drag on the air moving to and through the diffuser. In the 10' example, figure cfm at 6 psi back pressure. That's what I do.

Esshup - Very good description of CFM, air pressure, and diffuser placement. A+

Thanks Bill. Do you have any lifting rates for any other brand of diffuser than Vertex?

Soin order of responses:

1. I'm am also a dumg Aerospace engineer (what are the odds) and after having the phone rep check with 2 specialists, I gave up and asked the question here. That the CFM is air and nor water solves many issues I was having.

2. I think a single diffuser in the dropped in the 11-12 ft deep central location in the pond with a diffuser in the 10,000 gpm range will work. Looks like Vertex supports this numerical approach with their equipment.
3. I'm only willing to work so hard to make somebody elses equipment work. Pond Guy very formulaic with a three diffuser system that I'm certain will work but mostly certain is not really needed given the specifics of my pond and of my needs.

I'll starting looking at what vertex diffuser and compressor is recommended for my hypothetical # 2 above, but am always open to additional feedback and suggestions.

1997 pond, send me a pm if you want a quote with your email address. We are a Vertex dealer. They will have a price increase 4-1 so any orders placed before that day will be at the current price level.