Phosphate test kit?

[Ketso]

I have been using the API phosphate test kit and coming up with 2ppm on my tap water and tank water (even after a week in the tank). Someone (I forget who, but kudos to them) said that hobbyist grade test kits are inaccurate at low levels. If the standard, as it seems, is to dose your tank to 1-2ppm phosphates, how would I know how much is still in the tank if my kit isnt accurate? Why would API sell it if it wasnt accurate? Seems a bit out of character for them as highly as everyone regards their products.

I read somewhere that excess phosphates is a sure fire way to bring on algae. Is there a decent, yet affordable, test kit available to the hobbyist to test phosphates?

 

[rich311k]

The seachem kit is supposed to be very good. Excess phosphates do not cause algae. Nutrients out of whack or bouncing or low CO2 levels cause algae.

 

[tropicfishman]

I use API products, my phosphate test kit has always been fine. I'd put it up agiasnt anybody else's big expensive test kit. either way they all use the same reagent lol

 

[Purrbox]

The API testkits are good hobbiest test kits. Like all kits of this type they are meant to give a good idea the levels but are not going to be as accurate as the scientific quality test kits which cost an arm and a leg. The Seachem Phosphate test kit is supposed to be nearly as good as the LaMotte Phosphate test kit (scientific quality), and I actually find it much easier to read.

A good way to determine how accurate your test kits are, is to callibrate them against a reference solution. Since the reference solution has a known value you can determine how accurate, or far off your kit is based on the results.

 

[Ketso]

Thanks for the info so far folks!

A good way to determine how accurate your test kits are, is to callibrate them against a reference solution. Since the reference solution has a known value you can determine how accurate, or far off your kit is based on the results.

Anyone care to point me in the right direction for info on callibrating test kits?

 

[malkore]

Ketso,

basically you'd use something like Chuck's calculator to mix up a solution of, say, .5ppm or 1.0ppm concentration. a known concentration.
then you test it and see if your kit passes.

I've always used SeaChem's phosphate kit. $10, 75 tests, as accurate as you can get without going LaMotte or Hach.

 

[Purrbox]

If you look at the Sticky about KH Reference Solutions this will show you how to make a reference solution that can be used in calibrating your test kit. The procedure is basically the same for anything that you would test for, you'd just need to use a fert calculator or something similar to determine how much to add.

By testing some Distilled or RO water you can determine whether the kit is reading 0 values correctly. Further testing with the reference solution(s) will allow you to determine how far off the test kit is as specific values.

That's the basic idea of what you would need to do. So far I haven't seen any more detailed information, but would love to if someone else has a link.

 

[Glenc]

As per Malkores advice, I use the SeaChem phosphate kit. I have probably bought and tried just about all of them. I have the LaMotte phosphate kit as well. I did side by side tests using the LaMotte kit against the SeaChem kit, as the SeaChem was the best of the cheaper kits. The SeaChem was just as good. Save some money, get the SeaChem kit

 

[tropicfishman]

I'm goign to calibrate mine and see what happens, didn't knwo you could do that lol

 

[Argblarg]

I have the API kit and made sure it was accurate by getting a 0 reading with RO+DI water, then adding 2 ppm monopotassium phosphate using Chuck's calculator and testing, tested correctly.