1 -- You can use water or water with a little bit of bleach. Just make sure that you rinse it out really well before using it in the tank. If you smell any bleach at all, then it still needs to be rinsed. If there's hard water deposits, you can use vinegar and elbow grease to get rid of them.
2 -- I don't see why you shouldn't be able to. I say this having never used a sump like that. Is there a place for the cord to stick out? If the sump is acrylic you probably want to make sure the heater doesn't touch the sides. While it shouldn't melt anything, why take the chance? Incidetially, most people here recommend using 2 heaters, one set slightly below the temp of the first. That way, if one fails, the other takes up the slack.
3 -- I wouldn't. If you really like them, then you probably need to set one in a bucket of salt water, leave it in there for several weeks, and constantly test for anything and everything that can be tested. Seems like a lot of work to me.
4 -- The rocks you see in everyone else's tanks are the live rocks (well, base rocks + live rocks in some cases). Lots of places sell LR
, including your LFS
, liverocks.com, the list goes on and on.
is expensive, but by all accounts worth it. Like live sand, LR
is just rocks with critters, coraline algae, and bacteria. Lots of people buy the less expensive base rock and seed it with a few quality pieces of LR
. The base rock eventually becomes live. You need approximately 1.5 lbs of live rock per gallon of tank. More porous is better, since it has more surface area, which means more bacteria. Or, you can choose based on the amount and color of coraline algae, hitchhikers attached, etc. LR
is as varied as the life you find around it.
You can also make your own base rock. Check out the DIY
sections at www.garf.org