I live in Connecticut and opened my 21' round above ground pool last month.Got my water nice and clear with good chemical balance. I started noticing small green pea sized "floaters" and the same, but on the pool bottom after they swelled up and sunk. It would collect in the center of the pool bottom (approx. 3'-4' in diameter)when i would have the pump running. decided to vac it out quick so my kids could use the pool. usually would vac.out to the yard but i didn't have the extra bit of water necessary to do that. I chose to vac. thru the sand filter and totally restricted it until it would pop the electrical breaker and had to clean filter and replace with new sand. I had an idea what i was dealing with (bits of leaves in the pool) and it was confirmed by doing a search.... Caterpillars - We have a huge oak tree very close and evidently the caterpillars love oak leaves. They eat the leaves and poop in the pool. I found an article dated a few years ago with the same issue, although I believe it was in Maryland. Looking at online photos of caterpillar poop and what I had in the pool are identical. Do not vac thru filter, vac. to waste outside of pool. The pool is still crystal clear, the poop breaks apart while vacuuming to waste and can see the pool hose aimed to the yard looks like pea soup green. Anyone else have this issue. This was the first year with this issue for me.