Pond Boss Forums INTRO Questions & Observations Aeration question

Like most of you, I turned off, or moved my deep water diffusers for the winter. At what temp should I turn the deep water ones back on? My 8 acre lake is currently 50 degrees with virtually no thermocline. 1/2 of it is 12-18 ft deep. Thanks in advance...

jb - Not much activity for this topic. I will give you my opinion.
Firstly, assuming you have one already installed then the bottom line it does not make much difference just so you start it before the the pond develops strong stratification. However:
1. To get the most efficiency from your unit start it when the surface water is around 5 degrees(F) warmer or less than the bottom water.

2. It will also depend on how long per day you run the unit and how big and deep the pond is. Lots of theoretical "it depends" here.

3. Ideally you want to start mixing the water before the DO above the sediment in deepest water drops to 3ppm(mg/L) or even worse 0 ppm. Your goal is to keep the DO next to the deep water sediment above 4 or 5 ppm. NOTE: If the DO is above 4ppm ALL SUMMER in water next to the bottom in deep water, you do not need an aerator.

I does not hurt to run the aerator at least 2-4 hrs per day shortly after the ice leaves the pond or at 39 to 40 degF surface temp. The pond is very easily mixed at this time/temperature. You can wait till the water temp at the surface gets to 45 to 48 degF then turn on the compressor, still very okay. Warmer surface temps require longer aerator run times to get the pond mixed. Sometimes continuous running is required, sometimes not, it depends. Whatever it takes to keep the DO at 4 to 5ppm above the sediment.

Despite what many say about killing fish during mid or late summer aerator startup, you can install an bottom aerator anytime during the summer. BUT now you need to take proper precautions so you do not bring too much deoxygenated water to the surface all at once. Slow start-up or short run times the first few days are critical here. Novice aerator operators and poor advisors often result in fish kills during summer aerator start ups.

Running time depends on four variables: how big your diffusers are, the air flow volume to each diffuser, how deep the diffusers are located and how much water is in the pond.

thanks bill. i thought the answer to my question would be a simple temp. once again i'm reminded of just how much i don't know.

Aeration start-up could be as simple as one temperature, but that would ignore a lot of important inter-relating points. Not knowing any details or background info is how some pondowners end up killing fish with a bottom aerator.