I bought a 20" PFH-I/20" PFH-F PERFECT-A-LITE, from petsmart the same store my aquarium came from(10*20, 10 gallon - probably top fin)... To make it fit the light has little things to cut out and I don't know which ones cut.
I figured it out.. subtract the lenght from the mesure of the rim*2 then the width. Take a tape rule and figure on the pegs to take out(the ones outside the distance). For mine(10 gallon, 10*20[rim .5"] made by top fin, from petsmart) Both 1's, then 3 and c from one side.
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