[JHOV2324]

Last night I left my a/c on and this moring I notice the tank temp dropped to like 73-75 i usually keep it on 78, how bad is it when the temp in a reef tank drops and rises. I've left my a/c on before but never notice the temp in the morning.

[marrone]

You want to keep the tank at a constance temp but small flux aren't going to cause any problems. Just slowly bring it back up to the correct temp. If you're going to keep your A/C on all the time you may want to put in a heater in the tank, just in case the room gets to cold.

If you want you can even get a controller that will monitor the water temp and turn on the heater or fans when needed. It all depends on how hot/cold your apt/home usually gets.

[Reefer420]

i've had my tank go to 73 in the winter when I forgot to plug back in my heater - to 84 in the summer when my apartment got way too hot..

never lost anything, though somethings took a day or two to recover fully...but I don't have SPS or hard to care for corals either..

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[Aqua Pro Builder]

More likely heat will kill the corals in the Summer than coldness in the winter in the home environment.

[nycfish]

What is the cheapest monitor out there? I can't afford a chiller..I am just using a 5" fan shooting to the water. But it seems like not working too good..the temp is still alittle high @ 81 now. Should I add one more fan?

[marrone]

Put a fan over your sump and one over the top of your tank. 81 isn't that bad and if that's what it's topping out at, specially with the hot weather we're having now, I wouldn't worry about adding a chiller.

[loismustdie]

NYCFISH, What size is your tank and what kind of lights do you run? Also, what type of pump are you using for a return and what powerheads are you running for circulation. Some pumps (RIO, Mag Drive, MJ) add a lot of heat. Sometimes fans aren't enough depending on what is listed above. Also, when it's hot and humid fans are less effective. Like Morrone said, adding more fans will be helpful.
I always highly suggest buying a chiller. I understand that it is a large expense up front, but in comparison to what you've spent on livestock and equipment overall, the chiller really isn't that much. Paying money to restock your tank after every summer will outweigh the cost of a chiller. My chiller seldom runs before June or after mid-September. My June electric bill was a whopping $2 more than the previous month when the chiller did not run. Small price to pay.
JVOH running an AC unit is also good to keep the tank cool. At least that way, you get the benefit of a cool environment as well as the tank. AC units also act as dehumidifiers, which will help protect your house from all the evaporated water. Just keep in mind, as he learned from his mistake, to keep a heater in the tank, just in case. You can also get an airconditioner with a thermostat and set it at 78 degrees. This will keep the temp from dropping too low.
DEEPWATER did a thread in this section about cooling. Some good info posted. Check it out.