Is your cover solid or a mesh ?
I closed with a mesh cover at SLAM level and when I drained after alot of rain, I took samples at the top and 2 ft down. It was 0 and 6 IIRC.
A couole months later when it was time to drain again I used electrical pvc to take a bottom sample too and the FCs were 0 / 3 / 13. (Or something like that) I also tested the salt which had a similar variance with little up top and 3k down below. I got the bright idea to mix it and I tossed the drain hose onto the cover after I had drained enough. I ran the pump 20 minutes each on the left, right and center of the cover.
Mixing the pool with the submersible is part of my process now anytime I drain in the off season. I put the pump in a 5 gallon bucket per the @PoolStored hack to help protect the liner and dropped it to the bottom.
Draining will always be from the top now hopefully saving some chemicals down below.
I closed with a mesh cover at SLAM level and when I drained after alot of rain, I took samples at the top and 2 ft down. It was 0 and 6 IIRC.
A couole months later when it was time to drain again I used electrical pvc to take a bottom sample too and the FCs were 0 / 3 / 13. (Or something like that) I also tested the salt which had a similar variance with little up top and 3k down below. I got the bright idea to mix it and I tossed the drain hose onto the cover after I had drained enough. I ran the pump 20 minutes each on the left, right and center of the cover.
Mixing the pool with the submersible is part of my process now anytime I drain in the off season. I put the pump in a 5 gallon bucket per the @PoolStored hack to help protect the liner and dropped it to the bottom.
Draining will always be from the top now hopefully saving some chemicals down below.