measuring phosphate levels

[crazycat]

i just tried to test my phosphate levels using the seachem phosphate test. unfortunately the color the water turned, a pretty turquoise blue, had no relation any color on the chart provided with the test, which goes from yellow to green. when i did the control test (provided with the kit) the test also turned a very pretty turquoise blue. the instructions say the control test is 1 mg/L. has anyone else experienced this color discrepancy?

and i'm sorry (in advance) but i have to ask a dorky newbie question...how does 1mg/L correspond to ppm? (i'm sure this has been covered ad infinitum but i've searched and can't find the answer.)

 

[greenmaji]

ppm and mg/L are the same. Have you re-read the instructions to make sure your following them to the letter?

 

[crazycat]

yup. read the instructions VERY carefully. i'm going to call seachem on monday. have you used their test? did you get shades of yellow to green? it's very frustrating since i'm new to co2 injection and fertilization...i just want my plants and fish to be happy...

 

[greenmaji]

I have the AP testkit so I havnt used the Seachem testkit but its sounding like your not getting the correct reading.

 

[crazycat]

sigh.

thanks for your quick response. i'll call on monday and see if i can get to the bottom of this...

i guess it's not fun if it's not a challenge!

 

[greenmaji]

no problem, it really sounds like there might be something wrong with your testkit..

 

[Steve Hampton]

I have a Seachem PO4 test kit and have had several and all have worked flawlessly. Let's just go over the instructions carefully again.

Fill the pipette to the BASE of the bulb...not filling the bulb...the amount is critical. Squeeze the water from the pipette into one of the cavities of the test plate.

Add 1 drop from the small bottle labeled Reagent #1.

Add 2 drops from the larger bottle labeled Reagent #2.

Stir with the stir rod for about 5-10 seconds, wait another 20 seconds and you should have a color from yellow to yellowish green.

If you followed these steps exactly making sure to measure the sample correctly then your kit must be bad if you got a turquoise color. The #1 bottle turns the sample blue, the second bottle turns the sample a yellow to green color.

 

[travis simonson]

I had a very similar issue with the Seachem test kit. Their website recommends soaking the sample tray in vinegar for 24 hours to remove any possible reagent contamination. I tried this method and had no luck. In the end I determined that one or more of my reagents had gone bad. I bought a LaMotte kit and have had no problems since

 

[greenmaji]

I bought a LaMotte kit and have had no problems since

hmm.. I wonder why you didnt have any more issues with this.. Oh yea.. LaMotte!