I thought about that a lot. Basically, I can make 33gals of water at a time though. I am pretty sure that once I get my parameters back in line, I should be fine, so I didn't want to buy a new trash can for mixing salt water. I now have considerably more macro algae growing and a AquaC EV240 skimmer. Amazing that my Ecosystem setup runs flawlessly on the 90gal but didn't work very well on the 210 gal. On the 90gal I used a 30gal sump (33% of tank volume) but on the 210gal the ecosystem sump was only 40gals (19%). If I had to do it again, I would definately do the Ecosystem design again, but ensure that the sump/fuge was at least 1/3 of tank volume.