Help with coral growth in AIO

[Gk5321]

I bought myself an innovative marine 40 galling tank in July and when I purchased the tank I planned on keeping a majority of sps corals. For my equipment I have a max spect razor 120w, Smart ATO, cadlights skimmer, and a cheap power head that I plan on upgrading. The tank has been running for awhile now and I have a lot of corals in it, if anyone wants to know what I ahve I'll list it out, but I have just in sps about 20 or so different types. My water levels are perfect;
pH:8.2
Ammonium: 0 ppm
Nitrite: 0 ppm
Nitrite: 0 ppm
Calcium: 450 ppm (25-26 drops)
Alk: 8-9 drops
Mg: 1360 ppm

I test everyday and do 5-8 gallon water changes once a week. The corals in my opinion are living, not thriving. I never expected my coral to grow incredibly fast, but some aren't even growing at all. I'm not sure if it's just because my tank is so young or what. Some corals I put in start growing immediately including some of my acros, but they then stop. I have been over the last couple of weeks been adjusting my lights a lot and I'm not sure if that's why. I also just yesterday started dosing Mg, but I measured it before I added it and it wasn't terribly low. Can someone possibly recommend a way to deal with this? Also my Goniopora that I've had for 2 years in another tank isn't opening now :(