Pond Boss Forums AERATION Should I aerate? Intermitant Aeration

Although I do not have a pond, my cottage is in a shallow bay with no inlet and a very small outlet. The water pretty much stays there.So you could call it a pond. This is our first winter with running water from the bay. As soon as the bay froze over the water in our cottage turned dark and smelled like septic water. I did the research and found out it is caused by anearobic bacteria. I purchased a 3.7 cu ft per minute aerator, made a hole in the ice, tossed in the membrane bubbler and bingo, over night the water turned much more clear and the smell was mostly gone. This is a bay with 20 inches of mush on the bottom. This is a very shallow bay. I am considering getting other cottagers together to put a system in place to aerate the whole bay. Sorry this has taken so many words but here is my question. Electrical power is on smart meter in Ontario. From 7 pm to 7 am the power is half price. I am thinking of running the system only during those hours. If I did that, would the lack of oxigen in the off hours kill the aerobic bacteria that I am trying to cultivate to eat the sludge? Thanks in advance. I have been lurking for a while on this sight and have already found it to be very helpful.

Welcome, Brassman.
This is an interesting post. I don't know the answer, but there are some very smart aeration people here who will almost certainly be able to help.
A few quick questions to give the experts a bit more info:
How big is the bay?
How deep? [Or how shallow?]
Is it fed by runoff from a stream or creek, or is there some other way for a lot of organic material to wash in?
Does it have a lot of algae, plants, or other greenery?
Sorry for all the questions, the more info they have, the better equipped the experts will be.

Aerobic bacteria will probably be fine if you aerate at night, as there's likely to be a lot of photosynthetic production of oxygen during the day, if you have plants, algae etc.

This is a wooded area, no farmland, no fertilizer use and probably no septic tank problems. The bay is 150 yards wide by 350 yards long. Most of it has 18 inches of water with at least 18 inches of muck under that. The cottages are along one side and on that side there is a channel roughly 4 feet deep. Our cottage is halfway along and has the deepest area. [5 or 6 feet?] Most of the bay is choked with weeds but it is clear on a narrow channel on the cottage side mainly due to boats going through on the way to the lake. Very little water enters or leaves except for spring runoff.

Sounds like a neat place that you have there,Is the cottage in the water on an island? Can you post a picture(I can't) to show us what it looks like? I am trying to figure out breathing,so I won't be any help but there are several people here that will help you. welcome to Pond Boss and good luck.

If you had to pick a 12 hr period to aerate, night time is the best. Plants and phytoplankton use Oxygen when the sun is down.

Essup is correct, night time is the best time to aerate! Someone would need to run the calculations, though, to ensure that you are getting enough circulation in those 12 hours. If you would like to PM or email me the location of the bay, I'd be happy to run the numbers and see how many diffusers you would need and what CFM output to circulate the volume once per night.

Sue,
Any idea how much of the "muck" might dissipate/digest with aeration? I know there's no way you can give any sort of realistic estimate without seeing the place, but in your experience, in this sort of BOW where most or all of the muck is likely degrading organic matter [plants dying in place, cycle after cycle], is there likely to be a significant reduction?
Thanks.

That is hard to tell.... in one case that was followed over the course of 5 years in Michigan, they saw as much as 6" - 12" in a year. I'd say 12" is a little on the high side, but it was a very similar situation (a cove of a large lake). It would be interesting to follow this bay and see what kind of reduction they see after aeration....

I believe with the case in Michigan you also knew what the lifting rates were. Even though Brassman knows the cfm of the compressor one might want to explore the diffuser to be sure it was matched well to the air flow for the intended purpose. 3.7 cfm can be lot of air to release in a single area unless there is a lot of depth, Just some things to consider.

This little compressor that I have running is just meant to condition the water in the winter. It took just one day of running under the ice to get rid of bad odor and color. Treating a larger part of the bay would probably require much higher volume at low pressure. I sm looking at a ring blower with an output of 42 cu ft per min @85"water column.This will be expensive to run so,as I stated before, I plan to operate it 12 hours per day to take advantage of the lowest electricity rates. I also only plan to operate it when biologic activity is the highest. [june through august[ Now back to the original question.During the 12 hours that the blower is turned off,will the aerobic bacteria die off? Would the result be better if the blower were run 24 hours per day for the same number of hours per year?
P.S.I have been looking for line resistance charts and they are hard to find. Any links available?

It has been almost a year since I posted about problems in my bay. I now have 5 neighbors with aerators installed. After a lot of research, it turned out that if each one installed a separate system there would be a huge saving in hose length and less pressure loss/line resistance. I installed or helped to install all of the systems. Since depths are a maximum of 6 1/2 feet off of my property and less on the others, we went with 120 watt linear pumps at one per property. We run up to 4 diffusers per pump. Since in shallow water each diffuser covers a very small area, lots are required.
We are only trying to remedy our near shore area which is where the deepest water is. So far the one clear benefit is clearer non smelly water. This by itself justifies the small expense.

Two things come to mind here:

1) A better water source/well is needed unless you plan to boil your water

2) Aeration from a bubbler setup gets much of it's oxygen from the surface to atmosphere interface so keeping the area open continuously is best.

In WI we have quite a few lakes that get winter aeration to protect the fish from low DO. In MI they aerate in the summer only from what I understand as the DNR does not allow winter due to risk of accidents.

What has been done in WI is to simplify the systems. Move the air and skip the fancy diffusers. Diffusers will bio foul and require maintenance. I was highly involved as a volunteer with the installation of the "local" aerator that has nearly 4 MILES of tubing submerged.

What I am trying to say is that it sounds like you may be able to consolidate to a single machine and a substantial length of tubing with multiple discharge ports. It's not rocket science, it's all about turning the water over and maintaining an interface at the surface for aeration via mother nature.

Then again, since you already have multiple micro units available, you may just maintain present course. I'd suggest looking into some sort of renewable energy power source for operation and keep them running 24-7.

Water that we pump from the bay is for general household purposes but not for drinking. It is of much better quality than local well water, which is saturated with iron and manganese.
So far there have been no problems with the diffusers after about 11 months.
I am hoping for further benefits like muck reduction. I believe that I have seen some but not as fast as I had hoped.
With muck reduction I am hoping for some weed reduction but I have seen none so far.
Some of us have tried some bacteria. We think we have seen more rapid reduction from it but the cost is high. I think that I would rather get there slowly with aeration than spend the extra money.

Hi There I haven't been around for quite some time. We continue to aerate and have been adding bacteria sporadically. The reason being that the bacteria is crushingly expensive. But there is definite improvement as far as muck removal. In our bay, if you do nothing the muck will move in from other areas and make the near shore area completely unusable. So the system is keeping the muck down but is not eliminating it.
Back to the bacteria. I found a company that explains how to build a bacteria breeder at very low cost. It involves a 45 gallon drum, an aquarium heater and an air pump and stone. You take a very small amount of bacteria and some nutrients and let them multiply for a few days before dosing the pond. It is quite late in the season but I want to be set and ready to go in the spring. Sound interesting?

Brassman,
Would you PM me the info on the bacteria breeder plan. I am very interested.
Tom Sterling (Shelby County).

Thanks for the update. Interesting stuff. Great that you and your neighbors can cooperate towards a common goal.