U should be good at that temp , me I don't use no chillers or anything like that all I use is hydrogaurd 2ML a gallon and I'm good , I sued to have lots of problems with the roots cuz of the water temps but it all went away when I started using hydrogaurd I don't even check the temp in in the water no more ,, I'm no pro I'm just saying what works for me ,, growers love from the heart