Will the real KH please stand up

[JB Reefer]

New Neptune Trident I've gone through atleast 5 or 5 in the last couple years. Aqua Spin Calibrated last week. New Focustronic calibrated. And Hanna Alk tester tested 3 times same reading with in 0.1. 500 Gallon sps tank. What reading is correct?

 

[BanjoBandito]

That trident measurement doesn't look right....I don't think you can physically have those Ca/Mg numbers. The hydrospin is in ppm if I remember right, which means your alk is 3.5 per that unit. Focustronics are very busy....with all the doo dads. What salt do you use? What's your ALK normally? I kinda wanna trust the "least complex test" with the "least amount of variables"....which would be the hanna.