I have a 75 gal tank with clownfish, hippo tang, and yellow tang...with LR and soft corals. Temperature has normally been at 76 degrees, but in about a 36 hour period, temp dropped to about 66 degrees due to heater malfunction. I have slowly brought my temp back to 68 deg in 2.5 hrs. How fast should I bring it back up to 76 degrees? My livestock are all doing well at the moment, but I don't want to harm my fish in this process. Any help would be greatly appreciated.