Pond Boss Forums AERATION Systems questions confused about aeration???

S-Tarpon - This is why you are confused.. Aeration is a complex topic and not lots of basic scientific research has been conducted on aeration of small to medium sized ponds. Also many types of aerators are marketed that each operate a little or a lot differently. SO there are many THEORIES or opinions as what to do. AS many theories as there are salesmen! All "EXPERTS" have their opinion and VERY FEW have real test results to show you. Few are willing to take the time to design a unit, explain run times and maybe do some tests that are specifically for your pond.

In my opinion, different ponds and different settings have different aeration requirements. So aeration specifics for your pond will depend on several if not numerous things. General recomendations are applied to most all ponds with disregard to specifics of each pond's morphometry, eutrophic nature and locality (region/climate) and etc.

We have discussed winter aeration (for northern ice forming states) and compresor run times in several previous posts. Northern ponds circulate naturally during real early spring and then again late fall until free-up. Why run your aearator when nature is adequately mixing your pond for you?. First Search and Read past posts for more on this topic.

Some unique ponds will have oxygen on the bottom year round. These ponds typically do not need aeration (artificial or supplimental circulation / destratification).

For most all other ponds to be real accurate, basically you have to calculate how many circulations your pond needs each day (or week). This can be a hard question for most to accurately answer. Most advisors GUESS at the answer. Genearally speaking, young (newish)ponds with low nutrient loading need fewer circulations per day than older, and or nutrient & organic rich ponds. Internal pond temperature also affects number of required circulations. Circulations are designed to replace the "bad" water that develops first at the mud water interface (or in other deterioriating stagnant water zones) with better quality water from usually the surface (epilimnion or illuminated zone).

Most simply, I think you basically want to try and maintain 2 to 4 parts per million oxygen at the pond's mud-water interface. Higher values might be better. You definately do not want anoxic conditions (zero oxygen) to develop at the mud water interface. Anoxic conditions change the whole biological community on the pond bottom from a healthy zone to a septic (dead) zone. Septic conditions drastically slow down the decomposition rate of organics while producing additional chemicals that degrade water quality.

To get a real good handle on how many circulations that are needed one needs to do dissolved oxygen and biological oxygen demand (BOD) tests at several critical times and areas of the pond. Very few "aeration stores" have the ability to do these tests. These will provide static oxygen demand values to indicate when and how often the water needs to be replaced with water containig higher dissolved oxygen.

Also entering into this formula is the volume and strength of the surface boil and the volume of the pond and shape of the basin. These will also determine how fast a circulation can occur with a particular style of aerator.

Technically it can get complex but most simplify it by giving general liberalized answers to cover most all cases. These are the type of answers you have been getting. Confusing conflicting and some inaccurate.

The best answer gets complicated and can not be made without actual pond tests. So you will have to probably accept the generalized answers.

Typically I try to size an aerator so it does not have to run continuously. I try to achieve 4 to 8 hrs per day run times. This can in larger or irregular shaped ponds can require larger hp or multiple compressors which sometimes becomes cost prohibitive for the customer. Smaller sized units in these settings need to then be run longer times to get the necessary number of gallons of water moved to destratify and circulate and distribute oxygenated water to all if not most of the pond zones.

So to give you "good" generalized aeration answers one needs pond depths, basin shape, a general idea of the annual organic /nutrient inputs, average, min., max. water clarity, and maybe a few other aerator hardware item details. As I said in the begining it is not a real simple answer if you want a specific accurate or compelte answer. Every pond can be different and as the pond ages the answer can change due to the pond's features or inputs changing. I used up a lot of space and still did not really tell you much or give you a definate answer, but tried to explain why.

Get your unit from someone you trust to be knowledgable and is willing to take some time and discuss things with you. Also you need to be knowledgable enough to ask THEM some specific questions to get specific answers. You can always verify his answers with an experienced, educated and knowledgeable second opinion. Not all doctors were dedicated "A" grade students; some "just got by" and did as litle as possible. You probably don't want those "monkeying" with your body or your pond system.

PS. Initial installation. If you do not fertilize your pond and it settles out pretty clear and does not develop green colored water the first year,, then you probably do not need to install your aerator the first summer. Irreparable damage will not be done in your locale during the first year. But it will be better if money is availabe to install the first year and run it at least 3 to 4 hrs per day.

A one acre, deep pond (18' - 24')would probably be best aerated with a 3/4 hp rotary high pressure (15psi, 8cfm) compressor. This unique unit is made by GAST Mfg Inc& available from Stoney Creek Equip, Grant MI. This can be operated at 110V or 220V, is quiet, dependable, easy maintence and with a long motor life. Typically rotary vane compresssors operate at 10psi and release air to a maximum of about 18'; beyond that depth the compressors have shortened life spans. The deeper pond in your region and amount of snow cover is probably best for fish survival during winter(discussed for you in earlier posts).