I've heard some ppl say they built a DIY overflow box for their sump/refugium and I would like to know how to go about it. I have a 29g tank and will use a 10g for sump/refugium. Thanks for any and all info.
FWIW you may want to consider getting a good reliable overflow instead of building one, I was originally going to DIY one myself but decided that the extra peace of mind was worth the extra 40-50 dollars it turned out to be, plus you *shouldnt* have to worry about possibly replacing carpet, mopping up water when it fails, etc