New Hanna phosphate checker

[Delphinus]

I used to have one of the older, more expensive models. I have a couple questions about how it would compare:

1) How easy is it to get the reagent packets open and the reagent added to the glass vial?

2) I realize this would be a pain to find out because of the 3 minute countdown per test thing, but if you take several tests in a row (of different samples), how similar are the readings from test to test?