LaMotte Alk Kit Question

[newsalt]

I'm using LaMotte's test kit for alk. I have a question regarding the color change. Do you stop adding drops once you see the color go purple and use that reading, or do you continue adding drops until just before it turns red and use that reading.

[Bryan]

Did your kit come with a color card. The end point is the purple, past endpoint is the red.

[kaskiles]

I've noticed a pretty broad purple range in my kit. Seems like 10 or 20 ppm worth of purple...

Anyway, the color card purple looks a little deeper than the initial purple so I keep going with a drop or few until I get the deeper purple. I usually use the whole syringe just because you cannot reuse the titrant, and keep track of the first purple point and first red point, just to appreciate the spread.

[bdare]

I'm using LaMotte's test kit for alk. I have a question regarding the color change. Do you stop adding drops once you see the color go purple and use that reading, or do you continue adding drops until just before it turns red and use that reading.

I totally understand what you mean. At first I HATED my LaMotte kit. I was not happy with the gradual color change. I think what you'll find is there is a gradual slope to get to the "target" color and 1 or 2 drops more will turn the kit red.

When I use my kit and I think I'm getting close I'll check the value before each drop and keep adding till it turns red and backup either 1 or 2 drops depending on the color change.

I know this sounds confusing, but I think practice makes perfect with this kit. After you get used to it you'll see it really is as accurate as everyone says it just takes time...