@ iheartmybettas - thanks. its 36 inches long by 8 inches deep by 11.5 inches tall, meaning that each cell is 6" by 8" by 11.5" which is plenty of room for them, the 4 boys in there already are very happy in their new home!
i cant promise i can answer your questions, but i will forward them to my brother who built it and try to get answers for you. drop me them in a PM sure when the time comes.
@Lee - i live in NI man, we dont have walmart here. my bro works in a tropical fish shop, i believe he used fish-safe sealant yes, both clear and black. the dividers are made of strips of glass, so the tank is 100% glass, even the handles on the cover glass are glass. It took a few days to dry/cure, but so far so good.