First off, let me apologize for my lengthy post, but I know I should give all the info I can. Also, I'm not very good at turning thoughts into coherent paragraphs; please bear with me. I just inherited a real small (sigh... 10g) aquarium and equipment, most of which is/was new-in-box. I bought everything else that was needed along with replacing some of the inherited equipment that I didn't feel safe using and wasn't new. All in all here is my inventory: (purchased new unless stated except for 10g tank) 2 10g tanks (one covered in lime scale with cleaning equipment being stored in it, not in use; may not ever use it) fluorescent deluxe hood, incandescent economy hood (not being used), power filter (100gph, rated for up to 15g), corner filter (90gph, rated for up to 20g, not being used, kept as a backup, inherited), 50w submersible heater, 6 artificial plants, a couple different air stones, 2 air pumps and line (one was inherited and quite old,used a backup), 2 gravel vacuums (one was inherited, but was moldy/algae-covered; not being used), 2g bucket, 4 air-line gang valves (all inherited, not used), under-gravel filter (inherited, not being used), canister filter w/ separate water pump (not being used, for some reason it was being used with a 10g tank...; outlet nipple snapped off when moving, may try to fix it with some aquarium silicone), 20 lbs polished gravel (inherited, not being used, smells awful), 10 lbs black/mardi gras mix, bulk activated carbon and zeolite crystals (I assume for the canister filter, not being used), 2 thermometers one floating and one standing (standing one used during water changes in bucket), algae scraper, fish net, API freshwater master test kit, tetra 6-in-one test strips, pH test strips (inherited, expired, not being used) water conditioner, tropical flake fish food, flash-frozen bloodworms, start-zyme (dormant nitrifying bacteria). My current setup is the 10g tank, power filter, 10 lbs gravel, heater, all artificial plants, small airstone/air-line/air pump, fluorescent hood, and 2 (as of now) glofish. Now onto the problems and concerns. I have very undesirable tap water here; between 150 and 300 ppm GH and a little low on total alkalinity ~80 ppm KH and a pH of 8.4. I have bulk spring water with 300 ppm GH, 180 ppm KH and 8.0 pH. I can also get bulk distilled water. I cannot find a combination of tap water, spring water, and distilled water that has the GH, KH, and pH that wont stress the fish. Any ideas on this? Another problem with water, specifically temperature during water changes. Since my tank is kept above room temp every time I do a water change there is a difference of at least 2-3°F between the tank and bucket. I have herd some people using hot tap water to get the right temp, but I have also herd to never use hot tap water because it sits in a metal tank all day long and thus has a higher GH. I have thought of 2 ways to increase the temp of the water in the bucket; either point a space heater at it for a little while (incredibly stupid idea) or buy another aquarium heater and put it in the bucket. I have a few reservations about using the aquarium heater in the bucket. First, could the heater melt the bucket? Also, having to wait 30 minutes to turn it on and another 30 to turn it off and take it out of the bucket will get annoying very fast and there is always the (good) possibility I will forget to wait to turn it off and take it out of the bucket. Next problem/concern is I use an ultrasonic humidifier in the room the aquarium is in. since ultrasonic humidifiers atomize everything in the water, including heavy metals and chlorine, there could be microscopic bits of heavy metal, chlorine, and calcium in the air that could land in the aquarium. Is this a valid concern or am I worrying too much? If you need more info on anything, ask. Thanks in advance.