I want to build a wet dry for my 125. Does anyone know of any resource that can provide some good specs to do it right and economically? Any help would be greatly appreciated.
Anything from a 30g to a 55g tank would work as wet/dry's (I am currently using one of each, as I have 2 125g tanks myself). Personally, I would go with a 55g tank for a sump-wet/dry, just because you can fit so much biomedia into it, and you have a lot of space to set it up in different ways. Plus, it's such a big filter, its hard to overstock the tank
Search through the DIY threads, there are TONS of sump and wet/dry designs posted you can copy, or use as idea's for your own personal design.