First time fish owner

okay so i can't find this anywhere online that's helpful enough to me.i check my fish tank and it has a reading of the highest alkaline. 8.4 on the test strip.now i'm planning on getting armored catfish.two or 3 of them.will this kill them?if so how do i get rid of it?I have well water and the well water is a bit hard.now the water itself has only just begin to cycle and i just recently put the tank up.i got a thermometer which i can suction cup to the tank or it can free float.The temperature read's 72 degrees or a bit higher can't really tell since it's lines after the whole times and no middle number without the line's.I just added this tap water conditioner that make's it so the tap water is friendly.My other question is that stuff only for city water or is it for well water too?We get our water from whenever it rains and from the ground.Also how long before I have to turn the heater on for in order for the cycling to go a bit faster?I would post this on equintium but its down for now.so any help on tropical armored catfish would be much appricited since people here are faster to respond then any site i've been on.Also I am a first time fish owner and sites for tropical catfish would be helpful too.thanks.

thanks again

Jen