I would skip the algae pads altogether and get snails
I had spot algae and a magnetic algae pad, and eco complete.
bad combination. I ended up picking up the Iron heavy eco complete with the magna thing and scratched my acrylic tank.
NOW I have olive nerite snails from AZ gardens... they are brackish bred, but can live in fresh water without breeding.. and they are incredible glass cleaners. Haven't seen any algae on my glass ever since I got them.
No more pads, no more scratches!!!