Pond Boss Forums INTRO Questions & Observations aeration of a half acre pond

Does anyone know a formula to calculate how much aeration I would need for a half acre pond with max depth of 12 feet and mean depth of 5 feet? The pond holds about 4 acre feet of water. I can use both surface aeration and bubblers for maximum aeration if it is wise to do so.

Thanks.

Call Sue at Vertex, or I can do it for ya.

Try to find out what cfm is needed to operate your diffuser at good efficiency that will result in XXXXX gallons of water moved per hour. Four acre ft is 1,303,400 gal. 1.3 mil gal seems a little high in my mind for a 0.5 ac pond. My unmeasured calculation indicates the volume is closer to 2.5 to maybe 3 ac ft abt 814,000 gal which is more like the 0.5 ac ponds that I work with. If you take your gallons of water moved by the diffuser/hr (at 12 ft deep) & divide it into total gal, this equals in theory about how many hrs it will take to produce 1 complete pond turnover. Theory does not always equal reality - it all depends. Several variables come into play with what actually happens. Usually one wants to try and achieve 1 pond turnover per day. Several turnovers per day is better or good IMO which indicates oversized and extra strong aeration. Overkill IMO means the aerator gets the job done quicker and the compressor does not have to operate 24/7.

Bill:

If an overkill system was designed, would it be recommended to run it 24/7 if the pond had a build-up of muck that the owner wanted to reduce?

So now I need to find out which diffuser(s) to use in the little pond, how much air it need to run well and, and how much water it lifts. Any help?

I'll check on my calculations, but when we expanded the little pond I measured the water volume as 3.5 to 4 acre feet ( I used about 40 points to do the calculation and it is a bit over a half acre) so I figured calling it 4 AF would be safe.

I still think your calculations are in error or I am in error and missing something. Math is not my expertise but I calculate 3.5 acft in a 0.5 ac pond needs an average depth of 7 ft., and 4 ac ft needs an ave depth of 8 ft for 1,303,400 gal (0.5ac). Does someone see what I am missing?? Is a bit over 0.5ac = 0.52, or 0.54 or 0.55 ac?? Volume is fairly important for calculating accurate turnover time. An extra 100,000 gallons could require 3 extra hrs of aeration for mixing depending on size of diffuser/s and cfm of compressor. Many don't worry about turnover time and volumes in a smaller pond. Buy an aerator, turn it on and let it run 24/7. Too much aeration is better than too little in most instances which is one of several reasons why 24/7 operation is common.

Brian and Bill,Sue can provide a spec sheet on this project on Tuesday but in the meantime Ill offer this.Lets say two stations ( Vertex Shallow water and a standard model) are placed equal distance apart and the pond is 220 X 100, In this example lets place one station 73 ft from the shore and it is in 12 ft of water and the next one is in 6 ft also spaced another 73 ft from station #1.With a small single piston compressor (Vertex Air One Plus) with 2.5 cfm total and calculating backpressure of 4.5 psi and tubing runs at or near 200 ft (.58 ID Hi-Flow)you will lift 1200 gpm in 6 ft and 2000gpm in 12 ft per station for a total of 3200gpm. This equates to 192,000 per hour or 4.6 million per 24 hr/day.If the pond is .5 acre and averages 7 ft it is in the 1.138 million gallon range or 4 lifts per day, (run 12 hr and 2 turns)So then one may wonder why not just install one station central and run 24 hr.The lifting rate calculation is strictly mathmatical. It should not be viewed as turning all gallons in pond over 4 times in 24 hours. If you placed both station side by side in 9 ft of water ( the average of 6 and 12 ft)the calculation would still come out as 4 lifts but in reality many of the gallon both shallow and deeper than 9 ft would not see the full benefit, thus the reason to space the stations in a matter affecting as many gallons as possible. This is where the aerial maps become a real value. Also keep in mind that the shallower you are even though you have less gallons the more equipment it takes to (lift) aerate.Last example would be a Vertex station (two head) that is supplied 2 cfm in 6 ft of water lifts 2300 gpm but same unit in 12 ft lifts 3900 gpm.Very rarely do I size less than 2 lifts per day for warm water fish. Hope this helps.

PS Somewhere in the archives Sue listed the Vertex lifting specs of 5 different diffuser designs at various depths at 1 cfm per disc.

Thanks Ted, that is the kind of data I need. If you can find that link, I would be very grateful. If not, no problem, I'll talk to Sue this week and get the data straight from her.

Bill has been helping me a lot on this one. I think I understand the concepts better now!

Brian, Go to our website and link on to the diffuser page on the homepage (left hand colum) then click on Vertex Shallow Water Model and the lifting rates can be found there.

okay, thanks for the link and the data!