http://www.jlaquatics.com/phpstore/s...t_ID=tz-ps9004
http://www.jlaquatics.com/phpstore/s...t_ID=tz-ps9012
Just wondering if you had considered a Tunze. I use a 9004 on my RSM 250 and love it, bought it on Boxing Day so it was a lot cheaper then(~$130), but packs a punch. Just an idea.
If it's too small for your needs maybe a 9012, but you'd have to double check the sizing to make sure it fits.
I only have about 10-12 damsels and some rock and it skims great for me.