I still had to set up my old 50gal sump. Once I emptied it, the clear fiberglass resin I used to seal some pinhole leaks began to separate from the plexiglas. When I built it 15 years ago I used a hand scribe to cut some of the plexiglas panels. Cutting acrylic with a table saw will give you nice straight edges, cutting it with a hand scribe, um, not so much. One needs to have perfectly square edges to properly glue acrylic otherwise you can end up with leaks. So back then I fixed a few small leaks with fiberglass resin. After scraping all the old flaking resin I then reapplied clear fiberglass resin on the inside edges & this time I also incorporated some fiberglass mesh. I accidentally folded over one of the resin soaked mesh pieces onto an area of the plexiglas that I wasn't planning to cover with resin & it etched the plexiglas so it doesn't look very pretty...of course it just had to be the front panel.
The main thing is that it doesn't leak. After water testing it for a few weeks I finally set it up, placing my old skimmer inside along with the return pump & live rock (plus 20 years of coral skeletons from those specimens that didn't survive over the years, RIP). Now I can finally get the overflow working & get rid of all that scum floating on the surface of my new tank. In the photo you can see my old 120 & a table/cabinet thingy I built from an IKEA LACK table top, scrap aluminum & an old night stand. This holds a kalkwasser bucket and other aquarium related items. My LED controller & power supply are attached to the side of it.
