phosphat-e questions which i didn't find an answer to yet

[MalteseOne]

I have gently added about 100 drops over four days into my 200 gallon tank but see phosphates not dropping, in fact they seem to possibly be rising.

first , everyone like numbers and facts.
ph 8.16
alk 8.4
nitrites 0.5
nitrates 5
salinity 34
ammonia 0
temperature controller calibrated to 77deg +/- 2F

phosphates
day ppm
152 0.537 NEW GFO added
154 0.402
156 0.365
158 0.310
100 phosphat-e drops added over four days into overflow to filter
163 0.307
164 0.304
166 0.316
using hanna ULR (readings are multiplied by 3.066)

feeding schedule has been exactly 2 frozen cubes for 6 chromies, 4 tangs, and 2 clowns.

water level held nearly perfect by ATO loop.

i assume my ancient red sea cannister filter might be bad, so i ordered a 25 micron filter (smallest micron size i found). I also ordered a filter pad to put in that is 50 micron (smallest i can find). my system is not compatible with socks.

I know the dosage i applied was very small, but i never make big changes. i learned small trial, then testing, then proceed.

Am i correct to assume the filtering is failing and that the hanna reads higher when phosphat-e is not caught in filter? maybe i am overfeeding and thats why it stays high.

 

[Idoc]

I've used it and it rapidly dropped my phosphate levels. I'm not sure why yours is increasing again.

But, one thing to really watch with Phosphat-E...it will drop your alkalinity levels rapidly as well. You want to watch this very closely.