roni, green neons are my favorite fish. They are smaller and school better than cardinals. Best schooling fish in my experience is rummynose, second is harlequin rasboras, third green neons. But the green neons beats them both in looks. They are wild cought so they do best in RO water.
Now im looking for 100 blue axelrodi for my next project. A new ADA 120P
Are you using pure RO water? What are you feeding them? I think my tap water is fairly soft and I have access to RO water thought it would make water changes much more labor intensive. How well do 90 fill up the tank (how large are they compared to cardinals?)