What is the diameter of those reactors?
Has anyone seen clear PVC like in this ebay listing?
http://www.ebay.com/itm/like/131855689498?chn=ps&dispItem=1
You could get some of this clear PVC, 2 end caps and a couple fittings for a reasonable price.
A 3 inch diameter 1 foot piece was 22 bucks, 4 inch was 30 bucks, with free shipping. If you can find fittings in your local store, you could make a pretty nice algae reactor using this.
I just about got my sump setup, and was planning on doing all cheato in the fuge, but then I saw this post and am having second thoughts.