help with temperature

[mseepman]

I need some advice regarding what to do about raising the temp in my tank.

Due to a faulty thermometer in my mixed reef, my temperature has dropped a lot without me realizing it. I'm not sure of the timeframe but I'm guessing 3 weeks ago when things started to go downhill. I put in one of those cheap Coralife thermometers to get a new reading (purchased this as I don't have any LFS carrying anything better) and have found the temp to be 68F. I've ordered a new pinpoint already but for now I have to start fixing the problem. Amazingly enough, things have gone downhill but nothing has died. A few SPS have started to bleach though.

How fast can I bring it back up? Where does everyone else keep their temp?

Any help would be appreciated.