Stripes are notorious for being inaccurate .... The API kit is quite good. To get a really accurate test (not really need for the typical hobbyist), you actually need to do the test with reference solutions.
80 gal FW with 30 gal DIY wet/dry/sump.
9 fancy golds, 1 hillstream loaches, 1 rubber-lip pleco (C. thomasi), 3 SAEs, small school of white cloud minnows, planted.