Can I test for nitrate in freshly mixed saltwater as a "control" to make sure my test kit is working properly?

[damsels are not mean]

Just got some new hanna checkers today and tested high range nitrate. The result was too high to read, and the instructions say to dilute it if that happens. I cut the sample in half and added more water, same result. After a second halving I got 52! This result seems ridiculous as I'd expect everything to be dead or dying, but corals are growing and no fish or invert signs of stress at all. I haven't tested nitrate in a while but never got very high readings before and haven't changed or added anything in in this tank in a looong time. Can I test freshly mixed water (RO/DI + salt mix) and expect to get 0 to make sure the unit/reagent aren't the problem here?

 

[melonheadorion]

if you know what level your fresh water is at, then yes. assuming that it is 0, like it should be, then you could.

 

[homer1475]

It won't be 0, but should be a real low number(maybe even 0 on the high range kit).

I found out very quickly with the low range kit, our fresh salt mixes has some very low levels of nitrate.

 

[Jay Hemdal]

Just got some new hanna checkers today and tested high range nitrate. The result was too high to read, and the instructions say to dilute it if that happens. I cut the sample in half and added more water, same result. After a second halving I got 52! This result seems ridiculous as I'd expect everything to be dead or dying, but corals are growing and no fish or invert signs of stress at all. I haven't tested nitrate in a while but never got very high readings before and haven't changed or added anything in in this tank in a looong time. Can I test freshly mixed water (RO/DI + salt mix) and expect to get 0 to make sure the unit/reagent aren't the problem here?

You can do that for nitrate, but not ammonia. Many sea salts have trace ammonia as a contaminant in them (up to around 0.25 ppm). That should not affect y9our nitrate test though.

Jay

 

[DrMMI]

Just got some new hanna checkers today and tested high range nitrate. The result was too high to read, and the instructions say to dilute it if that happens. I cut the sample in half and added more water, same result. After a second halving I got 52! This result seems ridiculous as I'd expect everything to be dead or dying, but corals are growing and no fish or invert signs of stress at all. I haven't tested nitrate in a while but never got very high readings before and haven't changed or added anything in in this tank in a looong time. Can I test freshly mixed water (RO/DI + salt mix) and expect to get 0 to make sure the unit/reagent aren't the problem here?

By the way, Hanna does make a calibration set so you verify you Hanna checker is working correctly.

Marine Nitrite High Range Checker® HC Calibration Check Set - HI782-11

The Marine Nitrate High Range Checker® HC Calibration Check Set - HI782-11 provides a stress-free, straightforward way to ensure your handheld colorimeter is working properly and providing accurate marine nitrate measurements.

www.hannainst.com

 

[Randy Holmes-Farley]

By the way, Hanna does make a calibration set so you verify you Hanna checker is working correctly.

Unfortunately, those are not true standards. All they check is the electronics. It does not ensure the reagents or method used are OK.