Im not much for acrylic work so here is how I did mine.
First I logged on to a specific website, and found an AquaC Urchin.
I printed it out and studied it really well. Then I got online and asked questions about it. Then I went back to that website and looked at it again. This time I punched in some numbers and hit a couple buttons and a week later it was done.
Oh ok so that wasn't a DIY plan. But this was a cheap and easy BUMP to the top for you.
Checkout RC (reef central where I spend most of my time) I've built several beckett skimmers and mine fits under my stand about 28" tall. I made a longer injector tube to make up for the shorter profile. Do a search on "beckett skimmer" You can downsize the size of the tube for the smaler tank.