I've picked up a second hand tank, 8ft long 135gal that I'm going to set up for haps and peacocks. The guy I bought it from has had a red ear slider turtle in the tank since he got it back in May, so about 5 months. I've turfed the media in the canister filter and replaced it with new, and it was a bare bottom tank for his turtle so I'll be using brand new pool filter sand for substrate. I'm just wondering about the glass tank and silicone itself - I've always heard how dirty turtles are. Do you think just a regular water and elbow-grease cleaning will suffice, or should I bleach it (using a 10% bleach solution)?