[Uncle99]

So I see:
P1-Yelow tang, some mushrooms, and some palythoas, and two fire fish.
P2-I believe that's a torch (left) and Favia (right).
P3-Finger leather.
P4-Kinda looks like Xenia to me.

As for the torch, (if that's a correct assessment) it has stinger tenticles at night and packs a powerful sting to others so this coral give room (I give mine a 6 inch circle). Beside it, the Favia, same thing.
Be wary of corals with stingers in smaller tanks as they need room. I would just move either one.

IF your TDS meter is reading 0 (in fact I let mine go to 10 before changing out filters) then nothing more you can do fir water.

Check your food contents for phosphate, make sure you do not wash your hands with any soap if your going to put them in your tank, just water and dry.

Phosguard as a GFO only got me to about .1

Now I use ROWA, much more expensive but brings me down to undectable in a week.
For your size tank, 100g size would last 2 months ish.......and once to undectable.....take out the bag so you have some phosphate.....02-.04 for corals is great and nitrate 2-7ppm