You have to also keep in mind that a heavy cold rain with cloudy skies (especially if coupled with run-off)in summer can greatly reduce the plankton bloom and result in an O2 crash.
I don't understand the factors involved in that...
I'm not sure I completely understand that either. But after several extremely dry years towards the middle and end of July our area received unusually heavy rains for the season with overflows in my pond and I lost my bloom. For a few days the water turned a redish brown but it wasnt muddy and almost overnight it turned back to its normal unfertilized tanic/black very clear (visiblilty 3' or a little more). I acutually fertilized again around the first of August this year to get a bloom back.
Last year during the drought when the pond dropped so low and the water area was greatly reduced I was afraid to feed with so many fish concentrated in just a little over half the normal surface area of the pond. The water color stayed a nice green and I never saw dead fish.
This year after the heavy July rains I havent received much rain at all. As the pool level dropped I kept my bloom and visibility of about 18"'s but green color had a darker not as nice to look at color. Yesterday we received only about a half of inch of rain but the look of the water was a much nicer cleaner color of green and the visiblility increased to around 2'. But 1/2 inch of new water with no run off wasnt enough new water to dilute the pond. And although the rain water may have been cooler the actual morning tempature that resulted from the front that moved through was warmer than the previous several mornings by probably around 10 degrees F.
Anyone have any ideas on how all this is affecting the DO level?
And since equipment that can measure DO is so expensive is there a cheap way for us poor folk to estimate DO levels in our ponds since weather events can have such a rapid and dramtic effect on DO levels?
