04-13-2004, 05:08 AM
Join Date: Mar 2004
Location: Alachua, Fl
iTrader Positive Rating: 100%
I have used both Red Sea and AP NO3 kits. I find the Red Sea easier to read, but tends to read a little high at lower levels with some test solutions I made up.
For PO4 I have used Red Sea and Nutrafin. Here, the Red Sea is by far the better one.
Red Sea kits you read while looking down through the tube. I find this to be easier because it isn't affected by light intensity the way the other kits are, to my eyes at least. With the AP NO3, for example, the brighter the ambient lighting the lower the apparent intensity of the coloration, therefore the lower the reading.