Depending on the salt you use and your coral load you may have certain elements that get depleted quickly. One is potassium. I don't test anymore for anything but I did test my pottasium through a company and through my own test and sure enough the results on both were identical, very low.
When I remember I add potassium and I dose a couple drops of lugols a week. My iodate was also low and I added some salifert stuff and retested it. (2 months ago.)
If you are into Sps you will find if you keep phosphates and the other levels you mentioned in a tight range you will see your corals look just as they should. I'm getting more color on corals from allowing a .05-.10 phosphate level. A lot of idiots say to keep it at 0, which is stupid. You will have pale sticks if you actually have no phosphate available.
I'm actually the less involved with my tank I have ever been and it looks the best today it ever has. So I don't think you need anything except water changes and stability. My calcium reactor has been beast. My temp swing did claim a lame tort last week but its okay cause I've killed that same piece 3 times when my tank got to 82. Know when to give up on certain coral is also sound advice some idiots don't understand. Same with fish.
Okay see ya next summer.
Best Wishes,
Esteban