Do I really need a heater for cooking LR?

[Rikko]

Well, got a decent little chunk of LR with a couple of BTAs attached (woo!) but it had a little more growing on it than I really wanted.. Fortunately, the BTAs didn't really appear to like the bag on the ride home so one of them detached from the rock and the other came off with next to no effort (woo again!). Those two are sitting pretty in the tank, but I've got this nice shaped piece of rock to deal with.
I'm going to cook the rock and see if I can't get it to clean up before I risk putting it in a tank.
(For those unfamiliar with cooking LR, you essentially put LR in a dark container for an extended period of time to kill off algae and encourage the colonial bacteria to "work better")

Right now I have it sitting in a bucket with about 3 gallons of water and a MJ1200 shoving the water around.. I'd kind of like to get by without leaving a heater in as well (call it a mishmash of concerns about added hydro, overloading the outlet where I have the bucket situated, and the tripping hazard).. Think it'll be problematic? I expect the room would drop the water to high 60s minus whatever the powerhead will add.

Right now it's got a lot of forminiferans (I'd like to keep them but it doesn't matter that much), valonia bubble algae (that can die horribly, thank you very much), what looks like a nasty dark strain of chlorodesmis algae (too tough to pull off the rock.. that can die too) and quite a bit of corraline (I'd like to converse that if possible).

Thoughts?