My creative 27 gal. sump and 6 gal. ATO made from 1/2" rigid PVC board, brand is Sintra. Running a B.A. overflow system with a 1100 GPH return pump on this sump.
My 10G (maxed 5G water level) with my DIY denitrator, GAC in a bag, return pump and my midnight sump stirrer (small wave maker and air stone). This is my filtration system to support mixed reef (SPS dominated) cheaply and virtually no maintenance.