Deltec Phosphate Test not good?

[icliao]

I was testing my tank water along with water from phosban reactor and compare the result with RO and distill water.

I found the result colors from RO, distill water and Phosban water all almost identical but not matching any of the color in the chart.

They appeared pale yellow and I can only tell it is lower than 0.015, (perhaps 0.008ppm)

My conclusion is that the test kit is only capable to detect anything more than 0.015 ppm and not less. At least the distill water result should match or be very close to the 1st color (0 ppm) but it does not appear so.

I even test with a new test tube (without contaimination) and still yield the same result.

My aquarium water appear to be close to 0.015 but I still have some microalgae growth.

Does anyone has similar experience?

[Bullredchaser]

If there is no phosphate but you do measure nitrate you can still have algae. What is your nitrate reading?

[icliao]

<a href=showthread.php?s=&postid=8008039#post8008039 target=_blank>Originally posted</a> by Bullredchaser
If there is no phosphate but you do measure nitrate you can still have algae. What is your nitrate reading?
My Nitrate is very low with LaMotte test. (Difficult to read how much since it is way below the first color in the chart but has some faint hint of pink)

[icliao]

BUMP

[Ralph ATL]

I found the Merck Phosphate test kit of all the ones that I tried. (Sailfert, LaMotte, fast test)