Bernie are you using just GFO and GAC as far as the filtration is concerned? Do you have a refugium or use Siporax etc? What return pump are you using?
I don't have a refugium.
I do have a liter of Siporax and 1 liter of Matrix in two separate bags sitting passively in the sump.
I have a Eheim 1260 Universal pump for the return.
To catch large particles there is a filter sock.
The skimmer is AquaMaxx ConeS CO-1.
For water movement, there are two Ecotech MP40Ws.
And recently I re-introduced GFO and GAC in the BRS reactors.
Then daily I use AF Pro Bio S and AF -NP Pro to keep the nutrient down.
As of about 3 weeks ago, I also have started using Vibrant liguid aquarium cleaner.
N 0.5 (Salifert)
P is undetectable (Elos Professional PO4 kit)
However, the algae in the tank might have fooled the test results. And the colors of the corals are not saturate enough to my liking.
I need to clean the front acrylic wall about every 3 days.
By the way, since revamp, I have been using Tropic Marin regular salt but for the past two water changes, I have switched to AF reef salt because it is similar and less expensive. They seem to be excellent salts.