The same api master saltwater kit is available in many stores .
it’s for saltwater ( as it says on the label ) but as we are all aware hobby grade test kits have improved over the years
Api is ok and many of us have used them for years .
they will for sure tell you there is ammonia or high nitrates but the exact and accurate amount can be off
still for a quick test to see if there is any trace of ammonia I will do a quick 5 min api test .
back to the original post .
the fact there was 4ppm to 0 over night seams weird .
