I just received a Modular Marine overflow (1600gph) and I am so impressed by the quality that I wanted to share my thoughts. I currently run an Eshopps overflow, and I actually had to have the new Eshopps Prodigy overnighted from Amazon as a backup because I was worried the MM wouldn't arrive in time. The quality difference between the two is huge:
Modular Marine is hand-made from thick acrylic. The seams are glued with care (and with just a touch of excess glue along in the inner corners, exactly how I would do it to ensure a good seal). There are relief cuts where the acrylic is bent. There is a 2nd row of overflow teeth cut into the back of the internal box, giving you bonus surface skimming. The entire internal box is removable - it pushes straight into the bulkheads with slip fit PVC. MM also gives you a notch which lets the external box overlap with the tank's trim - this lets you run a higher water level in the external box, reducing noise and helping you full siphon start every time.
The Eshopps Prodigy L is flimsy in comparison, especially the internal box. Mine actually arrived cracked, which is Amazon's fault for not packaging it well, but thicker plastic would have survived. Another huge problem IMO is the removable weir is just a faceplate with teeth cutouts, which you place over a big rectangular hole in the internal box. When the power goes out for hours, water will leak around the edges of the faceplate, and drain your tank to the bottom edge of the faceplate, which could be about 0.5-1 inch below the bottom of the teeth cutouts. This could flood your sump.
Modular Marine is hand-made from thick acrylic. The seams are glued with care (and with just a touch of excess glue along in the inner corners, exactly how I would do it to ensure a good seal). There are relief cuts where the acrylic is bent. There is a 2nd row of overflow teeth cut into the back of the internal box, giving you bonus surface skimming. The entire internal box is removable - it pushes straight into the bulkheads with slip fit PVC. MM also gives you a notch which lets the external box overlap with the tank's trim - this lets you run a higher water level in the external box, reducing noise and helping you full siphon start every time.
The Eshopps Prodigy L is flimsy in comparison, especially the internal box. Mine actually arrived cracked, which is Amazon's fault for not packaging it well, but thicker plastic would have survived. Another huge problem IMO is the removable weir is just a faceplate with teeth cutouts, which you place over a big rectangular hole in the internal box. When the power goes out for hours, water will leak around the edges of the faceplate, and drain your tank to the bottom edge of the faceplate, which could be about 0.5-1 inch below the bottom of the teeth cutouts. This could flood your sump.
