you can get a chiller mate ...I'll find some links for you in a bit .Other options are keeping the pump somewhere cooler ,blowing a cool fan onto the pump , bottles of ice in the res (but they melt quickly)
I dont recommend h202 but it is an option & is good for making up like a bath to clean the roots in between res changes .(be very careful how much you use though)
If you have the temps @ 20oC then do everything you can to keep them there mate & you may be ok .... Light leaks will fuck you up bro , your friend is spot on :kusht::Sharing One:
Another big help LOTS of air .... check out the hailea v-30 & v-60's super silent pumps...they kick out some bubbles & I think both your girls need more ?.... it helps keep the res free of rot as well