Anyone out there using LaMotte Ca tests?

[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)?

 

[crumbletop]

I have not used LaMotte, but make sure you are reading it properly. The Salifert kits read backwards to the way I think -- i.e. you flip the syringe and read how much is left in it rather than how much you dispensed.

 

[gflat65]

These are direct reading to ppm. Whatever the syringe says is the reading (no charts). I had to find a conversion for meq/L to mg/L (or ppm) for the alk to make sense to me (never measured in ppm before). I wish I had more confidence on which test to trust since they are so different...

 

[gflat65]

How much effect would using RO/DI instead of distilled water have on the test? You put 1mL of tank water and dilute to 12.9 mL with distilled, but I used RO/DI. That is the only difference in instructions...

 

[crumbletop]

Shouldn't have an effect on the reading unless the RODI or distilled is contaminated somehow. Very unlikely with RO/DI that reads 0ppm

That's an awful lot of water to a strange dilution, though (adding 11.9 cc of distilled/RODI).

 

[ocd_mariner]

Hey, congrats to you gary.

I cant read my friggin lamotte calcium test kit to save my life.

 

[gflat65]

Isn't it fun, Chuck.

I always thought it strange to use so little tank water, too, Jack.

 

[cee]

I'd trust LaMottes over Salifert, but they are hard to read. With many test kits, the titration isn't over until the color had held for 30 seconds or so. That could be causing you to under titrate one of your kits. Also, the LaMotte color change is rather subtle, IME. I'm really liking my Elos kits, however, no room for interpretation on the color change there!

 

[gflat65]

Elos, huh? I'll have to check into them. I'm showing over 600 on my Ca with the LaMotte. It stays purple forever. When it finally starts flashing blue, it only takes a few more drops, usually, but it takes forever to get to that point. I'm going to have a local friend come by and test it with his and retest with both the Salifert and the LaMotte to see what two out of three say (I'll probably get a third range...).

 

[ocd_mariner]

Gary,

Now that you explain your problem, I have the same issue. I read that you are supposed to take the reading as soon as it turns blue. In the instructions, it says something to the tune of, if it changes back to purple after a few seconds, disregard it. So, if it makes that friggin blue shade for just a bit, then turns back, you still finish your reading there. If I take my reading when it stays happy and blue, like a salifert test, then it reads 4 gazillion calcium as well.

I really wish lamotte had a forum here, I'd love some interaction about the calcium tests.