New tank New filter

[wheel6251]

Hi everyone, I started my 90 gallon fish only tank back in January. Decided with my son they would love it so much gonna step up to 210. Trying to figure out what’s the easiest/best/cost effective filtering system for it. I’m considering the FX6, but it’s expensive in my LFS told me I would need two of them eventually. Any thoughts you have would be great. I tried to watch some videos on the sump, but got quickly overwhelmed. TIA

 

[Jekyl]

Sump, socks or roller and chaeto.