From the rotala butterfly, I made the calculations and I came up with 2.54 ppm of PO4 per week.

So if I put 12 ml of that solution per week I should take 2.54 ppm of PO4.

I divided to 4 ml each time I dose, so 3 times per week.

I do my PO4 liquid test and I found 0.3 ppm of PO4. I did the test, few times during the week and I have 0.3 ppm all the time.

My question is, where is the rest of PO4? my plants consume all the rest of PO4 and I left with 0.3 or is not actuall 2.54 ppm my solution from the calculations??