Folks, if you've recently upgraded or renewed your annual club membership but it's still not active, please reach out to the BOD or a moderator. The PayPal system has a slight bug which it doesn't allow it to activate the account on it's own.
I have used API, Red Sea, and salifert. I even ran them side by side for 6 weeks (I tested weekly) and all three were very closed to each other in numbers.
API is the easiest to use but when some of my numbers were off (during my 6 weeks) the API was on the low end.
Red Sea was nice but when you read the numbers it not what left but what you used so in a 1ml and the reading is 0.10ml you used 0.90ml which just got to remember that while checking numbers
Salifert is the easiest to read (if you read 0.10ml you look up 0.10 on the chart) but these kits are costly