So that's why the price jumped while I went to check out.
I guess I'll try again later; might just buy them from Amazon still (rather than the other seller on there) since it says they're temporarily out of stock.
Guess I can bump all I want now that they're sold out. Hey, maybe since it was apparently a small amount they sold, they'll actually honor it.
I have the 500 model on a 90 gallon and it's a great filter. Seriously considering chucking any other brand after using it--including my FX5 and Eheim classic. It's just easier to clean, quieter, tons of flow and built in UV. Only thing that worries me is how it will hold up long term. So, for now, I'm keeping the others.
Edit: The only criticism I will lay on them is the cheap plastic on the intake and output pieces. Filter itself is solid though.