Thank you, RiOnRoxXx!
My chilis (4 different kinds) spend months in contracted state - between months of the normal regular opening for a feeding. For some other people, they are open without these periods of - let call it - dormancy. I'm trying to figure out what they need for normal existence.
Let compare: the closest to your setup was tank also 90g, 15g sump. Combo PC light 110W, 11 hrs cycle. Also HOB overflow box, Eheim return pump, 350 gph, later changed on OR, 650 gph.
~100 lb LR, also mostly Fiji, but no sandbed, BB.
Also soft flow powerheads, 2 Seio 620 and Koralia2, 1900 gph comparing to yours 1700 gph. Filtration: also micron sock, changed daily, and ASM G3 skimmer, rated 250g. No UV, ozone, probitics didn't worked well, stopped.
Water change weekly (messy fish, later - non-photosynthetic corals), temperature 78F in winter, up to 82F in the summer. Instant Ocean in tap water.
I know, I know, but other corals are doing fine, tubastrea and diodogorgia spawned and larvae settled, new colonies grow. Even dendronephthya and muricella plectana are opened most of the time, without these closed periods. Diodogorgian and Christmas tree worms passed 2 yrs mark.
Feeding: much, much more. Then: 3-4 cubes of mysis, brine, plankton, Marine Cuisine, chopped seafood - for sun coral, equivalent of 3 cubes - for a fish, plus Formula pellets and flakes, pinch of dried cyclop-eeze, ZoPlan, divided on 5-8 times daily, for gorgonians ans sclero.
Mounting: prefers not to be upside down, but tried all.
From reading it was expected that chili corals prefers quite high flow. My observations were similar, but again, tried all.
Pretty close to your setup, only with no sandbed, tap water, more feeding, higher flow.
But: I started keep the first chili coral in a common reef, with significantly less feeding, skimmerless, aragonite sand bed, low ro medium flow. All the same.
What else you can think of - for me to pay attention to?
Unfortunately, DI water for me is possible only in pico system.mm
My coral when fully extended is about 3" long and wide. I bought this specimen at a local LFS that had no idea what it was and care on it. I scurried about on the internet and found the "basics" of the coral. 
I'll try to keep a closer eye in the upcoming days and see what I observe. 
