[Amanda_n_Jason]

ok a week ago i got a crocea clam for my 100 gallon and everything has been great i have been using my metal halides and t-5 lighting my problem is the past two days my tank has gotten up to 81.6 degrees and i have been switching my 1/5 hp chiller on and off to help with the temp spike it is a drop in style it gets COLD !!(i even have one of the power heads blowing the cold water towards the other end of the tank).....before two days ago it was running about 78.5 degrees constant i have a canopy (my fans for it are on the way!!) i havent added anything into the tank or changed anything...the lights are on a timer..t5's are on from 5am-6pm metal halide is on from 10am-2pm...the thermostat in the house has been on 70 for a while why did it change the past two days it seems crazy to me.. ..i'm just kinda worried because its not summer yet !! i'm going to get another thermometer tomorrow i have been using coral life digital therm. mine is a year old so maybe it needs replacing any ideas ?? the heater has been unplugged for about a month also

100 gallon 8 months old...i have two small/medium power heads and a skimmer no sump...yet

SG. 1.024
Ammonia 0
Nitrate 0
Nitrite 0
ph 8.2
CA 420

[greenbean36191]

How has the humidity been lately? If the humidity is higher than normal you will have less evaporative cooling.

In any event 81.6 is nothing to worry about since the average on natural reefs is about 83. You're tank is still running on the cool side. If you already have a chiller I wouldn't be too worried about summer temperatures.