Help and Advice

Looking at adding more water movement ,Currently got 2 jebao rw-8s on this 4x2x2 had them for a year now not had any problems,Problem is they are not getting rid of the crud in the rocks i manualy blast them everywater change which is every sunday .
Will avoid the maxspect Gyre asking price is too much for my likeing.

Question is what to add been looking @ the rw15s and adding 3 of them could also add a jebao cross-flow 55 however these units the cross flow seems to be getting some quite...