That powder is diatomaceous earth. It can be purchased less expensively in swimming pool supply stores.

It can also be used as a relatively safe weapon against cockroaches and maybe other insects. It is placed in a thin line by the edges of walls and molding. The very rough edges cut open the shells of whatever walks through it and the bugs bleed to death/ dehydrate. Thinking about that, I would want to keep it in the filter bags or compartment. We wouldn't want in the water column cutting the gills of our fish.

Bet the plants grow better in the 10. :)

Please do yourself and your fish a favor and don't get a "Chinese algae eater." They are really from Thailand (Siam) and grow up to be very territorial and more of the nasty "Thai Slime Sucker." When young they do take out hair algae, but there are other algae eating fish. For tank sides I would buy an inexpensive, soap-less, plastic pot scrubber and clean house once in a while. If there is a continuing algae problem. I might either buy more fast growing plants to compete with the algae for nutrients and to shade the algae, or do more partial water changes or shorten the time the lights are on daily by an hour or two.

There are better candidates among fishes for algae control. If you feed your mollies less, they may be a help.

I like the idea of your diary. Some century I also will post some photos and do what you, DJ and others have done. You may also want to copy your entries to a CD or DVD so you have an independent copy.