https://techenclave.com/threads/my-diy-aquarium-build-the-good-the-bad-and-the-ugly-anoxic-filtration.202272/
I used 3mm tile spacers, pinched the nozzle and injected silicon in between the glass panes. All 3 tanks, 3 sumps done the same way. Neat and almost zero bubbles. No leak test needed as...