Hi, installed a 1 acre pond in northern Ohio this summer that will have deep water ranging from 7 to 10 ft when full. The pond is currently 3 feet from full and slowly increasing with the limited rain that we have had. I have 800 panfish and 50 catfish stocked. I have aeration installed with two aerators installed at the 1/3 and 2/3 points of the pond. I am currently running them 1 hr on 1 hr off throughout the day and night.
How should I adjust for the winter? Should I turn one aerator off? Adjust the time schedule?
Thanks in advance, Tony
I doubt you need to do any aerating until the water warms up next Spring, except blowing a hole through any ice (too dirty to allow sunlight through it) that persists for a week.
If one of your diffusers is in shallow(er) water, that would be the place to blow holes through ice cover.
FWIW, I shut down aeration a week or so ago when water temps dropped below 50 degrees (2-3 weeks later than they do in most years).
Hi Tony- I think it can be helpful to share experiences and will add my winter aeration experience to expert advice by TG. I live about 70 miles to your NE. Our pond is about 1/4 s.a. and at least 35 years old. The deepest water is almost 10', but the "shallow" diffusers are in just 3' to 4' of water depth. (During the summer I operate a third diffuser in deepest water. I turn the water a lot in the summer, but I do that mostly because our pond was becoming eutrophic from leaves and organic waste- i.e. several inches of muck build-up.) I run a small, (80 LPM) linear diaphragm design compressor to push the air to the two shallow diffusers for the winter, 24/7. I began use of aeration the summer of 2019.
The first winter I ran the air at full flow from the compressor. This resulted in two fairly large openings in the ice that were sort of oval shaped and at least 15' in diameter. When ice out occurred I slowly lost about 20 bluegills and a bass. From what the county extension office shared and posts in this forum, I suspect that it was the red gill bacteria. Fish that were ill would swim slowly and seemed without directional control. Once the fish exhibited these behaviors, they typically died in a day or two. After some additional reading of articles here and in the PB magazine, I thought it was possible that I was turning the winter water TOO much, stressing the fish from causing even the deep water to become 34 or 35 degrees. So last winter I added a bypass valve at the pump in our shed that's 75' from the pond. I bypassed some airflow such that the bubbling at both diffusers looked more like an aquarium water filter bubbling. My goal was two openings no larger than 2' diameter. For last winter this reduced airflow reduced the ice openings to about 2' that I desired. More than enough to vent any bad gas and still allow some oxygen to mix into the water. And reduce the amount of cold water mixing during the winter cold. This past Spring I lost three or four BG and no LMB. Much better result. This small fishkill in Spring 2021 was more in line with what I have observed over the years. Most years maybe three or four fish die shortly after ice out and in some years none. I concluded that with similar minor fish loss this past spring as prior to using aeration, I may now have the aeration optimized for winter so added fish stress is minimal.
In the polar vortex winters of 2014 and 2015 we lost nearly all the fish in the pond. And those were the two winters with the coldest temps, thickest ice cover and no aeration. Maybe some of my experiences will help you. Admittedly I'm just 2.5 years into the use of aeration, but from what I'm observing, it has helped our pond.
I agree with Theo. For a new Ohio pond I would stop aerating around Oct 31 to Nov 10. New ponds with fairly clear winter water normally have low dissolved oxygen demand during winter. This means the high amount of dissolved oxygen in your pond water will last a long time after ice forms. Plus everything especially bacteria in the pond uses less oxygen in the colder water so oxygen lasts longer in winter compared to summer.
Ponds with lots of fall leaf input or those with dense weed growth or very green water will have higher oxygen demand during winter snow cover on the ice. Adequate light for phytoplankton photosynthesis will pass through even thick ice but not ice with 3+" of snow. Normally in Ohio we get a January snow melt and this again allows light through ice and into the water for oxygen production. Also if wind can blow snow off the ice this lets light through ice for plant oxygen production. I doubt you will ever need aeration in winter unless the pond has lots of leaf input, dense weeds or green water going into winter.
With 50 CC per acre, especially when CC are 16+", you should not get lots of summer submerged weed growth nor filamentous algae growth due to fairly turbid 'catfish' water that limits light penetration needed to grow weeds deeper than 3-4ft.
Thanks guys for the great info. Turned pump off and will only run one diffuser in shallower end when needed because of persistent covered ice.