Fluctuating Res Temps?

I turned my 1KW on a little early this season and have been having a little trouble with my res getting too hot, so I have been using 2 liter bottles of frozen water to cool things down. It gets up to around 76, and a frozen 2 liter lowers it to around 60 over the course of an hour, and then it creeps back up to the 70's over the next 3-5 hours or so. Is it bad for the res temps to fluctuate so drastically over the course of a day, or should I just be concerned with keeping it below 70? Thanks for any input anyone may be able to provide. :thumbsup::jointsmile:

I would think that as long as you can keep temp down near 70 or below you should be fine but I have nothing to prove this just my way of thinking :thumbsup: