If you already have an established tank regardless on if you have ich in the tank or not... just use that. You should still be leaving the new tank void of any life for several weeks to allow the cycle to start. which would kill off any ich in the tank anyway.
The tank has been sitting for 2 months already with what was dry rock and sand and 1 live rock. I also put in 3 fish that i had crammed in a 20 gallon in there. also my other tank has a number of problems since it crashed during sandy (haven't seen a nassarius snail or worm or pods since), not just Ich but i didn't want to sit here and write all this.. just wanted some sand with some life in it