I haven't wiped the inside of my glass tops for a long time, theres a layer of algae and lots of condensation. As i was taking the glass tops off today, the condensation would bead off and drop into the water releasing a bunch of nematodes with each drop. I looked at the bottom and there were hundreds of nematodes slithering on the bottom of the glass. Looks like i'll be wiping my glass tops more often.