I use a TLF150 on my 65g for pellets because I had one onhand. It does the job OK but you really can't fill it much beyond 2/3 full (if even there) because you won't get enough pellet movement otherwise to prevent a clog or partial clog. My opinion is that for pellets, a slightly wider diameter is better. The 2 other reactors I've used for pellets are 4" diameter and they are literally set and forget.
I'd consider using the bigger TLF reactor over the 150 because apparently it uses a 4" diameter. I can't speak from experience that it's any better as I've never used one of these though.
On my bigger tank I am using a Vertex reactor and it's basically "fill, set and forget (and occasionally refill)". I don't know what it is about it that makes it work, but I think it's a combination of the 4" diameter chamber, and the drilled bottom plate giving an even upflow. The exact model I'm using is discontinued but has been replaced with this:
http://www.jlaquatics.com/phpstore/s...t_ID=vt-uf15p1
... which seems to be more or less the same, except for cosmetic changes and larger diameter inlets/outlets (to give less flow restriction, which probably helps as well).
....
What is happening with your Cadlights?