Vodka dosing - Which Hanna checker???

[BillyC]

I'm trying to achieve ULNS by vodka/mb7 using sunnyx's approach. I need to know which hanna checker I need for PO4. The "phosphorous ultra low range" or the "photometer phosphate"?

Also, is the salifert nitrate test a low enough range for ULNS or is there a more precise test kit?

 

[bertoni]

The Phosphorus ULR Checker is a bit better, and that's what I'd get, although none of the hobbyist kits are precise enough to be useful for testing at low levels like those on a healthy natural reef.