Help! I dont know what is going on

[subsailor]

Ok so here is a brief background of what is going on. Bought the tank about 2 months ago. it is a 75 g oceanic setup with an oceanic trickle filter model 75. the tank has 48'" power compacts light setup on it right now ( will be swithching to the nova pro t-5 system next paycheck ) and also i am in the process of building a sump/refugium for it as i realize the trickle filter is a nitrate factory. So everyone knows i have kept african cichlids for a while but this is my first plunge into saltwater. all the parameters were good to go and the only inhabitants were a couple snails and a hermit or two and 2 neon gobies. temperature on the tank was 78 degrees steady. last week the temperature fell off to 72 and i checked the heater and it had gone bad so i replaced it with a 250 stealth. gtg or so i thought. the next day i bought some live rock from a guy in san marcos taking down his tank. Very nice rock lots of zooanthids, and various other things on the rock. got home got the rock in and everthing started to come out and show it self. then lights out which brings us to sunday. sunday morning got up tested the water and all was well. added a little purple up so i could facilitate corraline spreading to the base rock. day goes by checked the temperature as i was turning the lights out and whoa 85 degrees a lot of the little stuff on the rock had started hiding so monday morning and was in a huge hurry to get to work. lights came on didnt check temp etc. last night i get home and the temp is 85 degrees so i am thinking that somehow the power compacts are putting that heat out. btw my house is 73 degrees. i did notice most of the zooanthids etc on the rock are were not out yesterday. Is this due to the temp? back to topic so i added purple up and checked water parameters all good. i logged the temp 85 degrees. out goes the lights. this morning i get up and lo and behold it is 84.5 degrees i just dont understand i checked the new heater several times it is cold to the touch and is set to 78. what could it be. the return pump is also not warm. i beleive it is an ehiem hobby pump, it is also submersed. i am just stumped and don't understand what is going on right now. anybody have a clue? btw i went with the pulverized limestone seeded with 40 lbs of live sand. i love it so far.

[lcstorc]

For a reef system temp stability is more important than a specific temp.
The first thing you need to do is figure out what temp the tank goes to with the lights and pumps running. A lot of heat is produced by both. Then you want to set your heater slightly below that temp. I would do the testing when you are around for a couple of days and can monitor it closely so you don't have a large temp swing. If it is warmer than you want then ad fans blowing across the top of the water to increase evaporation. Fans over the sump can be helpful as well.

[lcstorc]

I almost forgot one other thing.
Quit using purple up. At best it is unneeded and many people have reported chemistry problems after using it. The corraline will come with stable parameters. Water changes are great to get things going strong.
If I remember correctly the Purple Up was raising the Alk to unhealthy levels. A search should bring up the right thread.