I'm running an almost identical DIY UC system as well. I've seen some really amazing results over at
THCfarmer forums and they have a whole section of their forums dedicated to this growing style. I'm glad
to see a few people adopting this style on these forums as well as I think the system is really great.
I made some homemade 9" netpots and run my water higher than most without any negative impact
but I don't think root rot can exist in the 67/68 reservoir temperatures I have.
How big were you planning on growing the girls out? I've heard that 1.25" pvc can still get clogged
when the root mass becomes very large so I'd keep a strict eye on that if you're growing out larger plants.
But that's only what I've read a few places over at THCF, I have no experience with 1.25" as I use 2".
Top picture is DJ Short Blueberry @ 12 days from clones, and the second is 3 sour diesel and 1
island sweet skunk.