nitrate/water question clarification

[saltwaternewbee]

I asked a question yesterday about nitrate testing with my kits and the LFS. I do know how to properly use the kits..thanks for the info. However I haven't heard the answer to the question.

Im wanting to know if heat/time effect water tests? Nitrates to be specific. My sample sat in the 100° temps for 13 Hrs before the LFS testes it. My nitrates were about 5ppm but I retested with fresh tank water and they were much higher. That's my problem. Thanks for advise in advance.

 

[spscrazy]

I would think it would but not sure if it were me I would take a sample & put it outside & wait how ever many hours you want & test & then test in the tank that way you will know if there is a difference, if your test kit is correct & if you need a new test kit and if time & temp matter in testing nitrate not much advise but maybe better than nothing

 

[Decalf]

I would say if the sample sat in the heat for some time the sample would become more concentrated due to evaporation and the your PPM would go up due to less water in the sample. ?

 

[robert]

I would trust your test - heat/time could affect water chemistry. It could also be that the LFS may not have tested correctly. For example, with API test kits - if you fail to vigorously shake the test vials between and after each reagent - you'll get very low nitrate results. With the API tests, I've seen water with 60ppm nitrate test out as 5ppm is the vials aren't mixed properly after each reagent step.