LaMotte Ca test kit questions

[gflat65]

I just got my LaMotte Ca and Alk test kits. The Alk test kits runs pretty close to my Salifert, but the Ca reads completely opposite. I only got LaMotte because of the recent issues with Salifert (I know it can happen anywhere, but the fact that it happened once with Salifert shows a break down in QA detection...). When I run the Salifert, it reads around 260. I wouldn't doubt that this is correct given that I can't add enough calcium to keep it balanced and haven't added in several days (I can do the two part with liquid because it takes me 4-5 heaping tablespoons every other day to keep calcium almost high enough...). However, the Lamotte reads somewhere between 550 and 630... There is no way that is correct (no coralline growth, etc.). I remember why I switched from LaMotte to Salifert initially (titration is much easier to read IMO-going from purple to a purpley blue isnt much help for me...). Anyone else notice anything like this (crazy readings, not difficulty reading the color change)?

 

[gflat65]

I knew there was something else I wanted to ask. In converting from ppm to meq/L, is it correct to divide the reading from the syringe in the LaMotte kits (ppm) by 50.045 to get mg/L? I think that is correct, but wanted to bounce it off of others for verification. I'm used to reading meq/L, but mg/L will work, too.