I just wanted to report some findings. After reading a blog post about the accuracy of nitrate test strips for determining accurate levels in soil and water (Accuracy of Test Strips for Assessing Nitrate Concentration in Soil and Water - Salinas Valley Agriculture - ANR Blogs
), I wanted to see for myself. So I purchased some of the strips the blog post said they found to be accurate. Hach AquaCheck strips for nitrite and nitrate. I then tested my water pre and post water change in my 40 breeder (50% every Saturday). I also tested my tap.
The results are wildly different.
Pre-water change API test kit: 40+ PPM
Pre-water change Hach test strips: 10 PPM
Post-water change API test kit: 30(?) PPM (the ? is because it was definitely red, but not as deep of a red as 40, but it definitely wasn't orange like 20 - so I split the difference)
Post-water change Hach test strips: 5 PPM
Tap water Hach test strips: 1 PPM
I didn't bother testing with the API kit as I know my tap has little-to-no nitrate.
Nitrite came back as 0 across the board with both API and Hach.
This leads me to believe that the Hach strips are indeed more accurate than the API kit - and if that is true - the API kit, when following their specific directions to test for nitrate, is significantly over-estimating nitrates in the water.
The next step is to get some distilled water and dry ferts and create a solution with a known PPM of nitrates, then compare test results with both methods. I've been using Thrive+ for ferts so I don't have any salts...yet.
I know a lot of people on here don't test and have little-to-no interest in testing water, just merely observe plants and animals and adjust accordingly. But some people, like me, regularly test their water parameters. If the Hach strips are the ones that are truly accurate, I'm pretty stoked about how low the nitrates are for the livestock, but it also makes me wonder if dosing should be increased for the plants. Only more time and tinkering will tell, which is half the fun of this hobby!
I hope someone finds this useful.