For starters the best test kit lwill be the one you find easy to use frequently but in my maintenance business I use:
API - pH, Alkalinity, Calcium, Nitrate
Elos - Phosphate
Nyos - Phosphate, Nitrate
Red Sea - Magnesium, low range Nitrate
Depending on what's happening I may tst everything frequently but normally:
Weekly I usually test for pH and Alkalinity and what I look for are long term trends. Some will say pH is not important and it does change throughout the day but it is the best indicator of CO2 we have and long term downward trends indicate increased eutrophication.
Monthly I test for calcium and magnesium.
As needed I test for phosphate and nitrate.
Whenever I buy a new test kit I will compare it to the old test kit to see if reagents have started going bad. I have found reagents can go bad faster than the "use by" dates and replace my test kits at least yearly.
Regarding Alkalinity test kits I've found API to be more consistant from one kit to another. I have a Hanna Alkalinty and compared it with a friends and using both reagent with both test kits gave us four different results that varied by 1 dKH. API comparisons were more cosnistant and using a test sample X2 or X3 larger then dividing by 2 or by 3 gives a more precise reading. But since reaearchers are using meq/l it's rare I feel the need to try to be more prcise than the standard API alkalinity reading.
API - pH, Alkalinity, Calcium, Nitrate
Elos - Phosphate
Nyos - Phosphate, Nitrate
Red Sea - Magnesium, low range Nitrate
Depending on what's happening I may tst everything frequently but normally:
Weekly I usually test for pH and Alkalinity and what I look for are long term trends. Some will say pH is not important and it does change throughout the day but it is the best indicator of CO2 we have and long term downward trends indicate increased eutrophication.
Monthly I test for calcium and magnesium.
As needed I test for phosphate and nitrate.
Whenever I buy a new test kit I will compare it to the old test kit to see if reagents have started going bad. I have found reagents can go bad faster than the "use by" dates and replace my test kits at least yearly.
Regarding Alkalinity test kits I've found API to be more consistant from one kit to another. I have a Hanna Alkalinty and compared it with a friends and using both reagent with both test kits gave us four different results that varied by 1 dKH. API comparisons were more cosnistant and using a test sample X2 or X3 larger then dividing by 2 or by 3 gives a more precise reading. But since reaearchers are using meq/l it's rare I feel the need to try to be more prcise than the standard API alkalinity reading.