Need Help with Calculator

[Spdjnky]

I feel not to smart first of all here are my notes on raising my Phosphates that I thought was right but I just don't know because this is a new reef aquarium with minimal aquascape and I only have my Yellow Tang left as I lost 5 fish a month ago and I still don't know why.I just can't seem to keep my PO4 above 0.

Trisodium Phosphate Anhydro
1.88 grams of Trisodium Phosphate Anhydro mixed into 1 gallon of RO water makes a solution that 1 ml will raise PO4 in 1 gallon of new mixed SW to .06 ppm.
10 ml added to my 90 gallon reef raised my PO4 to .02 ppm
So I have a gallon mixed and have got it up to .02 ppm last night and this morn back to 0 dosed 10 more ml just checked still 0.
Here is an Album of my aquarium.(

My 80 Gal Shallow Reef

16 new photos added to shared album

photos.app.goo.gl

)
I'm running the Triton Method and my Alk, Ma and Ca are all stable. So now if I can just get my Nitrates and Phosphates right. I'm trying for .03 to .07 ppm on my PO4 and 5-7 ppm NO3. I have been using NeoNitro and my NO3 is 4 ppm now it was 6 ppm yesterday. I'm out of that and want to use Sodium Nitrate and mix a gallon to use like I have for my Phosphate.
Thank You in advance for help I could not even think of how much less hair I would have if R2R wasn't here

 

[Flippers4pups]

What kit are you using for P04?

It’s likely being absorbed by the sand and rocks. This will continue till it hits a equilibrium with the water column. Dose a little at a time till you reach your target.

 

[Spdjnky]

I'm using a Hanna tester. It just seems like it's taking forever and I don't trust my calculations for my mixtures