As mentioned, having a lot of hardware on one GFI breaker is looking for trouble
I use a total of 13 GFCI duplexes and ran 2 15A circuits
'Almost' every individual piece of hardware I'm running has it's own duplex
The only things that are doubled up are;
My heaters, but there is another pair on a Ranco controller on it's own duplex, so no problem
My UV and GFO are together
My Skimmer and Carbon are together
My Return pump and Tunze Osmolator are together (on purpose)
My Chiller/UV pump and 'fuge' pump are together
I run 4 T5HO ballasts and have never had an issue with the GFCIs
The ballasts are connected through a PC4 power bar, so whether or not this solved any nuisance tripping or not I don't know
I also installed Surge supressor duplexes to protect the solid state stuff, like my Controller, Vortechs and Battery B/U, and ATO
I may have missed mention of it but are you going to use ground probes ?
I have 5
DT, Sump, ATO tank, NSW mixing tank and QT
Keep up the good work and enjoy your build