liquid vs powder test kits

[Liz]

so when I test my water with a powder kit my nitrates come to about 15, with a liquid they're over 60. What's the deal? Some guy said he theorizes that the liquid kits measure the dissolved nitrogenous gas (?).

[rwspear76]

I didn't even know that there were powder kits. Who makes them?

[Liz]

Aquarium Systems makes them, but I hear they're going out of production. Someone told me they were more accurate than liquid...

[Crown Royal]

Use Salifert and never be in doubt again.

[plah831]

I've used the powder tests. Not for nitrates, though, but ammonia and iron. They work just the same. I compared results with my trusty liquid test, and it was basically identical. The only difference is that the powder is hard to dissolve, it takes quite a bit more shaking than with liquid reagants. I'd say ease of use is the only real difference.

I'm willing to bet that the liquid reagants are just pre-dissolved powder or crystal solutions, anyway. They've just made it a little more convenient for us :)

[rbell219]

i was told today that the powder NItrate test kits seperates Nitrite from the readings. If there is a little Nitrite, the liquid Nitrate test will show elevated readings. Test for Nitrites next time to see.