I have a 11 gallon all in one shallow frag tank for coral qt. I ran kalkwasser coupled with ATO for a month or so but couldn't figure out how much I need to dose it. I switched to GHL doser 2.1 with 3 heads. One head is for ATO, another two are for auto water change. I set it to change 4 gallon of water in 7 days span. Weekly water test and PO4 is fixed at 0.03 ppm, NO3 at 1 ppm, dKH at 8 and calcium at 1300 ppm. I have been running this setup for 3 months now, coralline algae is growing on the frag rack now and I have some acro which have good polyp extension. I use one Kessil A160 with controller on this frag tank, and yes there are shadowing on some acro stick.
I did coral dip (Bayer + Revive) before I introduced them to frag tank.