I am struggling with the concept of DO levels in my little 1/4 acre pond.
The aeration system currently runs from 3am to 8am and the water temps and DO readings (among all the other test results) are consistent throughout the water column when the system shuts off, so I know the pond is getting successfully turned over at least once and probably twice by my calculations in this time period.
Last weekend's morning tests resulted in water temps at 75 degrees F top to bottom, DO levels at 4ppm from the surface down to about 2-3 feet, and secchi reading at 23". Aeration had just shut off for the day and by the time 6pm, rolled around, I had the following test results...
Water Temps - Bottom 75 F - Top 82.
DO - 6.5 ppm @ surface, 4.9 ppm - 12" down. 4.0 ppm - 24" down.
secchi - 23" (stayed there all day long)
This suggests to me that the current algae bloom is really helping the upper water column with respect to DO (still not all that great really). Whereas the aeration system appears to not do so much for me. Maybe it is keeping the DO from really falling off at night, but it kinda looks like it's ruining the upper levels of water.
I am wondering if mixing in the algae bloom at night is hindering the overall DO levels. My thought is that an algae bloom strengthens during the day, makes decent O2, then at night it gets mixed throughout the water column and has to struggle again the next day to build back up.
I am currently going to gradually increase my air time and check the water next weekend to see what it does.
Somebody straighten me out...surely I'm missing something in my logic. AND, what should I try to do to improve these DO levels?
