I'm setting up a 3 gallon cookie jar as a planted nano. I had a heater in there that I was removing today because the weather has gotten nice in a hurry here and it's really really ugly in this tank. When I pulled the heater out the suction cups holding it in place stayed stuck to the glass, so I put my hand in and grabbed the first. It came off, but had a coating, approximately 1/4" thick, of translucent slime on it. The tank has some guppy fry, a few ghost shrimp, and some plants at the bottom. Until today it wasn't receiving much light at all.
The slime looks and feels like the gel that is used to fill diapers once it has absorbed its load of water. It's completely odorless and was only stuck to the suction cups, so I'm inclined to think that it was a chemical substance of some sort rather than a crazily overgrown bacterial colony or some such. When I tried to remove the second suction cup, its coating fell off and broke into a million pieces which are floating around in the tank. I'm trying to do water changes to get rid of the bulk of it, but it's pretty much everywhere now.
Any ideas what it might be (it didn't photograph at all) or a clever idea on how to get the gunk out of the tank?