I'm not quite sure what the question is but I'll hazard a response.
The water temperature should be AS CLOSE TO your tank water as you can get it. Also, if you are NOT using well water then you MUST use a dechlorinator, and mix it in before you add the new water to the tank. I recommend 25% water changes a week minimum regardless of tank size/stocking.
Finally reached 6 tanks... oh god, this addiction is getting serious. 75g mbuna tank, 65g gold severum, 55g OB peacock breeding colony, 30g(36x18) growout, 20 long Dwarf Alto's, 10g fry tank.
If I die young bury me in... An 8x2x2 with versa tops and a large sump for adequate filtration;)