Pond Boss Forums AERATION Systems questions Aeration for a 7' deep 1/2 acre pond

I could really use some advice.

I have a pond that is ~20k sq. feet. - just under 1/2 acre. it is oval in shape - about 150 x 120 feet. Just measured the depth in a few spots and it is 7'. The water level is high this year and this time of the year so in the middle of the summer I'd estimate as low as 6'.

I'm told when it was dug it was 10-12 feet deep and can only assume it has become shallower as organic matter has decomposed and created muck.

Electric power is about 375 feet from the pond.

I've had very different advice form those that sell aeration equipment. Most suggest a diffuser system with multiple diffusers; some say 2 some say 3. One of the systems I've been recommended are the Kasco Robust-Air RA2 and RA3 system. Another is an Airmax system for shallow ponds; best I can tell the latter just uses extra diffusers - 4 but pumps out less air as it does not have a rocking piston compressor.

I've had another pond equipment and fish hatchery owner tell me that an aerating fountain is the only thing I should consider and that is all he recommends.

The down side of a fountain to me is that I need to run electricity to the pond and it will use quite a bit more electricity. If it is the right thing to do though I will do it.

My goal is not for a visual effect but aeration to limit algae/weed growth and help clear the pond (along with dye and bacteria to eat away at the muck)

I'd appreciate any opinions on :

1. Should I be going with something like the Robust-Aire RA2 or RA3 diffuser system I should go with a fountain.

2. Is there any material difference between the Airmax 'shallow pond' system that would make it better (rather than just cheaper) for a shallow pond vs. a Robust-Aire system?

3. Is it reasonable for me to assume that with aeration and beneficial bacteria the pond depth will increase as the muck gets eaten away by the bacteria?

Thank you!

canoetrpr,

I use a rotary vane compresser that is 1/4th hp that puts out about 4 cfm to two diffusers in a pond that is similar in shape to your pond and only slightly larger. My max depth in that pond is 9 feet. It has served me well for two decades.

Don't be afraid to buy the components separately to save money. Be wary of overpriced turn key systems.

As far as a fountain or surface aerator, unless they pull water from the bottom of your pond they won't do your pond much good, but look pretty, cost a lot, and waste power.

Welcome canoetrpr.

An "aerating fountain" is almost an oxymoron,,,as Cecil said, they do look pretty and please a lot people, but as for aeration, your hatchery guy is either very mis-informed, or just wants a sale and doesn't care that it won't fulfill your needs...even bottom draw styles do only slightly more than no useful aeration.

I won't knock a Kasco product, but Vertex is the industry leader. Email Sue Cruz with Vertex, and she will suggest the best design, style and location of placement. You will never go wrong with Vertex.

6-8 feet seems awfully shallow for Ontario to avoid regular winter kills. If aerating in winter, the diffusers are used in shallow areas only to keep some holes open and to avoid super-cooling the water below 37 degrees or so.

Diffused aeration can leave your compressor at the power...run the air tubing to the pond...it is WAY cheaper than copper! Make sure the air supply tubing is buried, and always going down hill if possible or moisture build up in the line will freeze and plug your supply.

Based on the information you provided you should go with a sub-surface aeration system because you are over 5' deep. Since your power source is 375 feet from the pond I would suggest one of our systems that use a piston compressor. We use piston compressors in all of our larger system, we don't use any rotary vane compressors. With the piston compressors there is no need to run power to the edge of your pond, the air can be pushed that distance. This is a benefit of sub-surface over surface aeration plus there is no cord in the water which is a plus if you use it for swimming. If you wanted to run power to the ponds edge you may be able to go with a smaller aeration system. Using 1/2acre and avg depth of 5' you have about 842,000 gallons of water in your pond. Go to www.aerationsupply.com and look at our genAIR systems. There are many to choose from if you want to run the power to the pond. If you don't look at the genAIR-145PM. See link below.

http://www.aerationsupply.com/catalog/sub-surface-aeration/small-pond-aerators.html

As far as the muck it is possible that you have 3-5' of muck sitting on the bottom. Look at our Pond Patrol Sludge Remover Bacteria Pellets.

http://www.aerationsupply.com/catalog/po...ge-remover.html

I really appreciate these thoughts.

I got a system design by Vertex and it surprised me that they only recommended a PondLyfe system with one diffuser (Shallow Water) for my setup.

Kasco recommended the RA2 system with two diffusers and I've had others recommend a vendor assembled custom system with a 1/3 hp rocking piston compressor and 3 diffusers.

I don't know yet if I should believe that one so called Shallow Water diffuser from Vertex will be better than two "normal" diffusers from Kasco.

Both the Kasco and Vertex Air1+/Air2 systems have me a bit confused as I can't tell if they come with a splitter valve or whatever is needed at the pond's edge since I will be installing 375' away.

My land is quite flat so I don't really have the option to install uphill :-(. I wasn't going to bury the pipe except in spots where cattle or the tractor is going to cross; I have a whole pile of irrigation pipe which is the same material that I've run along a fence. I never thought about the issue of moisture freezing up. I've had vendors tell me they often run the pipe above ground as well so I better give this careful consideration.

I WISH I could afford the $10k or so to dig out this pond another 5-7 feet!

I think you can try the above ground airline to see if it will work in your application. Be aware the condensate collecting in hose valleys/dips could freeze enough to block the air flow and this will occur during winter aeration when aeration is needed most to prevent fish kill. Also be aware condensate could drain downhill back into the compressor and damage it ruin the pump. Try to prevent both potential problems. If the above ground application causes problems then bury the airline 3"-6" deep. Try to get all piping to travel down hill or install a water trap in front of the compressor.

Bottom aerating 1/2 acre can be done basically two ways: a. with low air flow/volume (small pump 1-2cfm + one small diffuser) and run continuously or use more air flow/volume (bigger pump larger diffuser)and then mix it stronger for a shorter period of time (several hrs daily). You are in a cooler climate so IMO continual mixing is not necessary. One to two mixes a day is enough for your location and application to maintain oxygenated water on top of all the bottom sediments.

If you try the on top of the ground airline, please return later and let us know how it is working - pro and con.

About that muck, many here have said they can remove 'feet' of muck either through aeration or through beneficial bacteria supplements plus aeration. I was discussing this with my family member the other day and they asked a simple question... Where doe 3 or 4 feet of much go to? I gave it some thought, I didn't know! IT would take maybe a 100 dump truck loads to remove 4 feet of muck from the bottom of a 2 acre pond, yet somehow the muck disappears? Where does it go? Do the bacteria use it like food and turn it into motion type energy and not produce any waste products (outside of their own heat from metabolism?) Do plants pick it up and turn it into other biomass?

Curious minds...

Well I finally decided on a system and hope I didn't do wrong. Found a dealer half way across the country who took some time with me and found a good solution for me. I'm getting a Vertex Air 2 system except without the Vertex cabinet. Instead I'm getting a cheaper "Poly" cabinet with a fan and ventilation built in.

The dealer realized that I was just putting the cabinet in a barn on a farm so suggested to me that I really didn't need to spend the extra money on the fancy Vertex cabinet but he strongly recommended their equipment. So all the components; compressor, diffusers etc. are the Vertex system.

He managed to convince me that I am better off biting the bullet and trenching. Considering I have access to a friend with a backhoe who has offered to trench for me, I might as well do it. Now he did suggest burying it 2.5 feet deep so I guess I'll do that. The land is flat so it can't be uphill to the compressor unfortunately.

I guess I could install a check valve at the compressor. Is this what you mean by a water trap Bill?

I've had quite a bit of farm runoff into this pond over the last few years. I made the mistake of not fencing it off from the cattle and since I got the cattle, weeds and algae have exploded. Suspect getting the water moving will do it some good. Cattle have been put up for sale so the situation won't continue.

I built my own cabinets out of 2 X 4's and plywood. Never even painted them and they are still solid after 20 years. Honestly don't know why you need a cabinet indoors.

Cecil, there is a certain amount of tranquility that I like even around the barn. I'm sure professional farmers would get a kick out of this but I enjoy my time adding bedding to the pole barn and essentially cleaning up. As a R&D guy by day, barn chores can be therapeutic! So the cabinet primarily serves to muffle sound and with a bit of acoustic foam and a poly cabinet should do the job well.

One word..... Vertex. Research them, do some product quality comparisons and I think you will see why they are the best there is. A shallow water A-Max system is a gimmick and will not net you the increases in water quality that you are looking for. Very low pumping/lifting rates and not worth the investment.

As for wanting to use them as a weed and algae control devise... anyone who tells you they will cure those issues is just looking to make a sale. Although some reduction can be noticeable, it is not the case all the time. Look at it as a tool to increase the water quality, help your fish population and reduce organic buildup.

I agree with Cecil that a cabinet inside the barn is not really necessary and a luxury. The pumps are not that noisy and once installed if it is too noisy then order a cabinet.

A water trap would be a T or 'drop line' in the airline where any water draining back through the airline would collect in the drop tube (leg of the T). The end of the drop line should have a ball valve so the water can periodically be drained out. I prefer the drop line to be made of clear vinyl hose so you can seen when water is in the drop line. They make T connectors with the leg of the T a larger size or diameter of hose barb thus you could make the diameter of the drop line larger diameter than the airline. Install it so water cannot drain back into the compressor unless the drop line is full of water. I use water traps mostly when the airline goes up hill or when pump is in a basement and compressor is below or very near the pond water level.

Bill, thank you very much. This is excellent advice. Will definitely install a drop like as you suggest.