Dan,
Thanks a lot for the help, I really appreciate it.
To clarify, I don't have any skimmer issues at this time. Water quality is fine, for now. The skimmer I have is simply underpowered for this sized tank and stocking rate. It is an older model Euroreef (the one with the foam piece). It may be a CS-5 or -6 - whatever it is, I'm sure it's not rated for over 135 gallons. I bought it several years ago as a blem, and don't recall the model number,but it fits the dimensions of the CS-100 (
http://commerce03.i2net.com/able55n...rotein-Skimmer--SALE--with-Bayonet-P16C6.aspx) - mine is just 20" tall, and that gives me barely enough clearance to unscrew the collection cup for cleaning.
It pulls plenty of foam, and I clean it often. It's actually never been used until I recently put it on the 210. I was going to try to cram an AquaC EV-120 in there with it, but I dropped the #&*% AquaC last week and broke it due to being nagged by my husband to put it on a shelf with no room. He did not understand why I got red in the face and cussed him out after I broke it. He has no idea how much it cost.
Thanks for the suggestions on the sump. I may actually be fine, I may just have it overfilled, let me check.
jda,
for the reason stated above, I do need another skimmer. It's really a toss-up between one rated for a ~200 gallon system, or one rated higher. I want the best value, obviously, but am willing to pay more for performance. I'm also limited by the space in my sump.
If I ever get a larger system, it will require a larger house.

No plans to move soon, so I need to live with the 210 for at least five years.