 Temp. low while curing for about 18 hours...
I got my live rock yesterday and started the curing process at about 6pm. When we left, the water parameters were fine, 1.021ish salinity and temp. around 74 F. Last night I checked on the temps, and one had dropped to about 70F, so i turned the thermo up a bit and went to bed.
This morning I checked the temp again, and it had dropped to 68. I am thinking now that I've just been turning the damn knob the wrong way, so i turn it back the other way a bunch and head to work. I had my wife check the temp later and it was still 68.
I'm wondering if this low temperature is going to permanently harm my rock. I have a brand new heater to get the temp back up, so hopefully no lasting damage will have been done.  _________ I've got a new hobby! 
75g R.E. Tank (48x18x21), 29g DIY Sump, 70lbs Tonga LR, 90lbs Substrate, 4-65W (2-10k + 2-Act.) 48" Compact Coralife Light, Super Skimmer 125 with output mod, 2-Seio 620 PH's, QuietOne 3000 Pump
2 A.C. Ocellaris Clowns, 1 Bicolor Blenny, 2 Cleaner Shrimp, 2 Emerald Crabs, Purple Striped Mushrooms, Blue Mushrooms, Red Mushrooms, Spaghetti Leather, 1 Pink Finger Leather, Green Star Polyps, Pulsating Xenia and 2 Large Feather Dusters! | 
good luck and best wishes 
