Well first off I have a par meter. I didnt know anything about your light before I googled it. Looks like they are about the same wattage. I am able to pick my intensity and kelvin. Mine is 100% at about 7500k. I turned down my pink/red channel to 50% after about 2 weeks. It was giving the feather caulerpa a weird look. My guess even though lights and water clarity are different we are getting roughly the sameish par. We cant rule out lighting but it can go on the back burner. I am using the fluval 3.0 plant light 22w version. I just cut back on the schedule for the light from 12hrs to 9hrs, 30min ramp on both ends. - How long is your light on?
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@Crabs McJones said it may very well be nutrient based. I typically feed heavy. I feed two pieces of nori a day for the tang, flake on my lunch break and typically a mix of frozen, half cube mysis and half cube of reef plankton or a large squirt of arctipods at night. I feed the lps a cube of brine or mysis 2 times a week. I add 5oz mixed live phyto every other day. The tank is new only about 2 months old with marco dry rock. I have heard it absorbs phosphate but I can detect it on a hannah ulr. I have only done 2 water changes on this tank of 15g each. Its roughly 120 total gallons. Tests come out the sameish weekly 15-20 nitrate and 0-.03 phosphate. It may well be higher if I didnt have macro. - Feed more or dose.
Flow could be an issue too not getting the nutrients to the macro. Years ago I wanted a display fuge but it just kept looking like any other fuge you typically see. Someone with a very nice macro tank said up the flow youd be amazed what that will do so I added a couple power heads didnt have gyres back then. I used 2 maxijets with pvc pipes on the outlet turned into a spray bar type thing. Basically a backyard gyre. I aimed them from the back of the tank to the front across the surface of the water so as the flow hit the front glass it would travel down and back toward the macro. Immediately things looked better not even a week. On this tank the returns dump here first and I used an elbow to aim the flow at the front glass of the fuge section. The flow hits the glass and "rebounds" back toward the back of the fuge. The flow of the sump goes from right to left also. My algae dances gently in the currents created.- May take care of your coating issue.
Hope something from that helps.