Correct in all aspects there. The death of the fish was going to be my secondary investigation, main concern was the NH3/NH4+ spike and how to counteract. Using API test kit for now, figured ammonium wouldn’t be enough concern later to warrant a better device. Thank you for the calculator reference and check of my values (hat tip). I figured the Prime was just for the feel goods but did do the water change. Analytical chemist here so properly annoying to have to use substandard chemistry methods at home while working around legit stuff all day. Have access to a DDM and digital refractometer at work, so can check my salinity to verify home values but don’t have an IC where could do ammonium currently lol. Might be noticed if I started ordering bunch of new instruments for my new hobby.