I woke up this mornign and when I turned on the lights of my 29 the angel's fins were clamped. I took an amoniia reading and it was between .25 and .5 ppm and there was a film on the surface of the water. One of the two aqua clears rated for 50 gal tanks had stopped at some point. the bio balls were dry, but the foam filter media and the activated carbon were still wet, but I'm not sure of the temp. the filter was hot, but not hot enough to hurt my hand. I restored flow did a 20% water change. The angels are active now. no film on the water good over all circulation.Could the heat damage the benificial bacteria? if so how long does it take to buid back up? should I check water parameters before going to bed? and do another 20 % water change?
