yes it might. But most people that know me know i hate small tanks, So if i upgrade to a 140 gallon i won't need a new skimmer. also i like to over feed my fish..Hi! Welcome back! I have the AC170 on a 75g + 30g sump, and it totally rips the system. The AC200 might be a bit bigger than you'll need for a 90g. NYreefNoob might be able to share his experience since he had the AC200.
I would build one and make the center section for the skimmer. You can make the baffels the same height as the recommend depth for the skimmer. The water level wont budge!
my total would be around 135 gallonsi just got the alpha 200 love it i also got the automatice cleaning head for it i think its called the vector ,i have 200 gallons total in my system i contacted vertex and asked them which one they would recommend for my system cause i wanted to go with the 250 but shot me down and said the 200 would work better the 250 is overkill and wont skim right ,im def happy with my 200