Pond Boss Forums Thread Like Summary - Oxygen readings. What next?

Yes, aerators and lower feeding completely wiped out the algae. However, I got in my oxygen probe so I wanted to get an idea of the levels at the pond. See the pond pic and the readings. I was not expecting so low readings at 8’+ Note, my probe is only 10ft max. Temp yesterday over 95 and no rain in weeks.



A1: Aerator diffuser 1
A2: Aerator diffuser 2

Main top spring: 1’ - 4.85mg/L - 69F

T1 Site: 2’ - 11.34mg/L - 85F

T2 Site: 2’ - 12.34mg/L - 87.6F
T2 Site: 4’ - 11.15mg/L - 87F
T2 Site: 6’ - 10.24mg/L - 86F
T2 Site: 8’ - 6.57mg/L - 84.9F
T2 Site: 10’ - 0.08mg/L - 84F

Took another reading 3ft away from A2 @ 9ft = 1.7mg/L - 82.5F

I’m using 5.7cfm compressor with bottom diffusers. Seem’s to be kicking of plenty but I’m stunned by the drop to 0 when I get to 8’+. Should I move both diffusers to deepest sections? I’m not getting any foul smell. They’ve been running for a few weeks now 24/7. I was concerned about having most diffusion so close to the spillway. That is why I have one up in the shallow by the spring. Thoughts?

Let me clear up some misunderstanding.

1) The goal of a bottom diffusion aeration system is to bring O2 to the bottom of the pond, so the fish have the whole water column to utilize, AND bringing O2 to the bottom of the pond will allow aerobic bacteria to colonize the organic matter at the bottom, which in turn will greatly reduce the amount of annual muck accumulation.

2) Placing the diffusers on the bottom in the deepest part of the pond is exactly how a system is supposed to be installed.

3) A properly designed and installed bottom aeration system will show minimal water temp change from top to bottom, and will also show minimal O2 differences from top to bottom. That is the purpose of a bottom diffusion aeration system.

4) When installing a bottom diffusion aeration system in a pond that has a thermocline set up, with a very low DO reading at the bottom, it is critical to use the correct start-up procedure to prevent a fish kill. You WILL kill the fish in the pond if you just turn the system on and walk away. It's not the low O2 water that is killing the fish, it's the H2S gas that is killing the fish.