I called around to a couple of local acrylic guys to get a quote on cutting a piece of acrylic for me with two holes in a piece of pre cut acrylic to fit my filter socks. $40-50 for just the holes. Which sounded crazy to me.
After some google search I tried using a dremel.
http://reefcentral.com/forums/showthread.php?t=908525
Some posters said it wouldn't work other said it would.
I thought I would give it a try.
I used the hole cutting guide attachment.
Shownn here: (
https://www.homedepot.com/p/Dremel-C...FZJmfgoddRAJ-A)
First I drilled a hole in the center of the desired circle and inserted the cutting guide pivot. Then I drilled a hole at the edge of the circle. The pivot set inside the center of the circle and the drill bit in the hole at the edge. Finally I cut swiveling around at the pivot. I set the depth of the dremel to go halfway through the 1/4" acrylic on the first pass. Then increased the depth and finished the cut on the second pass. The speed was set at 15000rpm and I pushed it through the acrylic to keep it from staying in one spot too long and causing it to melt. Worked awesome! The holes were rough but sanded them down.