Pond Boss
Posted By: dr3131 Aeration question - 04/29/05 11:19 PM
I have a new (last October) 1.5 acre pond which is very deep(46') It was this deep so they could get enough clay to line the sides as my soil is very sandy. I live in NW Ohio. I have been told that I don't have to aerate for the first year.
What kind of aerator should I purchase?
Is there a down side to placing an aerator 46' deep?
Any other special considerations I should be thinking about with a pond so deep?
Thanks in advance
Mike
Posted By: Theo Gallus Re: Aeration question - 04/29/05 11:46 PM
46 FEET?

Are you going to put in a dock, or a U-Boat Pen? ;\)

I don't recall hearing of any smaller ponds anywhere near that deep. Your temperature profile is gonna be really interesting. You may be able to stock cold water, cool water, or warm water fish, year-round, depending on what depth (temperature) you bring water up from with the aerator in the Summer.
Posted By: Cary Martin Re: Aeration question - 04/30/05 02:57 PM
dr3131-

Conventional aeration systems should be placed no deeper than 35 feet. This is due to the fact that you will be compressing atmospheric air that is composed of mostly nitrogen.

Just as a diver gets the bends when going too deep for too long, the same can happen when a standard aeration system is placed below 35 feet.

In a 1.5 acre pond that deep, a single diffuser system will work fine if you be sure to suspend it no deeper than 35 feet. Allow the remaining 11 feet to be a nutrient sink.

You may be able to build yourself a large FAD (Fish attration Devise) out of PVC and sink it to the bottom as well.

It all depends on what type of fish you want to raise in your pond. If you are going for trout, then everyting I just typed will not work for you.

The system will warm the water too much to raise trout.

With a pond that deep and small, normal wind will not be able to circulate water to the depth of 46 feet. You may be fine the first year but rest assure that you will have stratification in the lower regions as well as build up of carbon dioxide and hydrogen sulfide gasses by the end of the season.

The best time to install a destratification / circulation system is before you have a problem. Why do you purchase health insurance before you even get sick?

If you have any other questions, please do not hesitate to post...Have a great weekend!
Posted By: Bruce Condello Re: Aeration question - 04/30/05 03:06 PM
Cary,

If this landowner wished to raise cold water species are there any hypolimnetic systems that are economical enough to be in reach of the typical pond owner? Are hypolimnetic systems subject to the same problems at depths of 35+ feet as a normal system?
Posted By: Ted Lea FOREVERGREEN Re: Aeration question - 04/30/05 11:59 PM
dr3131 I sent you a PM
Posted By: dr3131 Re: Aeration question - 05/01/05 12:48 PM
I was pretty surprised when it was all done and the final depth was figured out.
I just stocked Fatheads/Shiners and Perch. I will be putting SMB in the future.
Thanks for the information. As usual, it is very helpful.
Posted By: Cary Martin Re: Aeration question - 05/02/05 01:19 PM
Bruce-

Good question. To date, I am not aware of any scaled down Hypo system on the market. Since it is rare to have a small pond with such depth, the market for such an item is not enough to support the design work required.

Yes, hypos when placed at a depth greater than 35 feet will have the same effects. The TVA has experimented with many different methods of increasing 02 at depths greater than 35 feet and the best solution they have come up with is pure 02 pumped through soaker hose at depths greater than 35 feet.

You may be able to acheive the same results using a hypo housing but pump pure 02 opposed to atmospheric air. Of course the homeowner would not want to have a tracktor trailer of oxygen delivered every week to keep that system running.

As an aquaculturist, you may understand this option: Build a compressor house on the bank, pull water up from the Hypo and let it go through an 02 concentration cone that is connected to an oxygen generator. As the water passes the pur 02 generated by the system, it is gravity fed back into the hypo...just a brain storm.

Anyways, it was a good question.
Posted By: Cary Martin Re: Aeration question - 05/02/05 01:23 PM
Once again, I did not check spelling prior to posting...please excuse that Tractor word...
Posted By: PaPond Re: Aeration question - 05/02/05 10:52 PM
Cary,
You mentioned that aerators shouldn't be placed below 35 feet because atmospheric air is mostly nitrogen. Oxygen in surface supplied air never exceeds 21% even if you're pumping to 50 feet. I would think the reason for the 35 foot depth limitation was because of the horsepower efficiency of pumping that much air to that depth. Is the effectiveness of aeration due more to the oxygen percentage of the gas or the ability of the gas to move deep waters towards the surface where they can naturally be aerated more efficiently?
Posted By: Cary Martin Re: Aeration question - 05/03/05 12:07 PM
PaPond-

You are right about the equipment to push air that far down. It can be done with enough money.

But it is not the concentration of oxygen that is the limiting factor but the ability of the aquatic animals to off gas the nitrogen at depths.

At that many atmospheres below sea level, the nitrogen gas builds up in the blood stream of animals (fish mainly) and they are not able to release it through respiration. The result is what is called gas bubble desease whereby the fishes scales are lifted and open for infection and parasites. This gas will also build up in the joints of the bones a.k.a in scuba divers as the bends.

The pure 02 is easily off gased through normal respiration therefore it does not build up in the fish.
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