Red sea Phosphate test kit reading zero?

[Scorchx1245]

Been battling cyano, and a bit of GHA after my doser quit working on a 10 day vacation. (I also have 3 gallon fuge Keith cheato)Was dosing 15ml of vinegar a day. Long story....anyways 40b with 10g sump. So I went to test nitrates after a 3 weeks of water changes and and switching to nopox, tested 40. Still high but there down from 50 the week before...tested phosphate. Got 0...so I said this cant be right.... tested 2 more times got zero. Could this be right? The test kit is brand new. My RBTA looks like crap and my monti color is dull, stylo polyp extension is meh, my green slimer acro has burnt tips. My purple acro STNd to death. My LPS looks ok. So here are my numbers....
-Ca 420, alk 8.5, mag 1380, ph 8.0, salinity 1.025, nitrite 0, ammonia 0, nitrate 40 (salifert), phosphate 0 (red sea)

 

[Scorchx1245]

I only run carbon no GFO.

 

[Larry L]

I have seen a couple posts here and there about people getting zero readings with e.g. an API test kit but then getting high readings with a Hanna checker, but not sure if that is reality or user error. I don't know how Red Sea's test is different than other brands but might be worth getting a test done with a different kit, maybe at a your LFS.

 

[DesertReefT4r]

Sounds like the carbon and nopox dosing has bottomed out your po4. Dose Neo Phos to increase po4 to bring nutrients back into balance. This should help with no3 consumption and cyanosis issue.

 

[Scorchx1245]

I ordered a salifert, my LFS uses red sea as well.

 

[Scorchx1245]

I'll look into dodging neo phos aswell.

 

[PatW]

The recommended level of. Phosphates. Is less than .03 ppm and greater than 0. Red Sea’s accuracy is plus or minus .02. That means you could have a decent phosphate level of .02 ppm and still have a reading of 0. Only the Hanna ULR is sensitive enough to give useful readings on phosphates.

 

[Larry L]

Red Sea’s accuracy is plus or minus .02. That means you could have a decent phosphate level of .02 ppm and still have a reading of 0. Only the Hanna ULR is sensitive enough to give useful readings on phosphates.

Even with the Hanna ULR checker you still need to be aware of the accuracy, which Hanna says is ±5 ppb ±5% of reading. So you could have a zero reading on the checker but still be actually at 5 ppb phosphorus, or 0.015 ppm phosphate. So a little better than Red Sea in that case, but not by much.

 

[Scorchx1245]

Thanks guys. The cyano boom exploded after no vinegar dosing, it was nuts. Everything just seems out of wack almost like a crash. I'm sending in a Triton test soon. Just cant get a handle....I didnt think a carbon dosing failure would be this big of a deal. My birdsnest is now STNing....ugh... wonder if I'm doing to many waterchanges aswell. Doing 25% every 3 days. Obv rodi.

 

[Scorchx1245]

So I started to dose p04, got my first reading 0.01. And its holding, nitrates down to 25. Didnt think adding phosphates would help get my nitrates down so fast... but it may have. I dosed a round of chemiclean yesterday afternoon. Hopefully put the nail in the coffin.