I use the test kit where you fill the test tubes with water and but drops in it and then compare the color to the card. I don't use the strips. I feed them goldfish once or twice perday and try to give them krill too but they usually leave it to rot so I have to fish it out. I make the mistake of feeding them steak and they loved it but the grease or whatever make the tank pretty cloudy so I stopped that. I will put a powerhead in the tank and invest in more filtration and see if that solves the problem for now.