test kits?

[mark]

My only experience is Hagen and Salifert. Can't say if one is more accurate than the other, just found had more problems trying to match the colours off the cards with Hagen, Salifert easier for my eyes.

[DanG]

Based on new (haven't been on the shelf for over 1 year), I found that both Hagen and Salifert gave me results for calcium that were within 10ppm of each other, so I have to believe they're fairly accurate. The big thing I think that Salifert has going for them over Hagen is ease of use. Hagen is 1 drop, put the cap on the test tube, shake, repeat. not so much fun when 1 drop increases sensitivity of the reaction in 20ppm, for calcium of 400ppm, you're looking at 20 drops.