Milwaukee MA887 - precise but not necessarily accurate?

[rck329]

So I got one of these a few months ago and it's been a weird experience.

When I cal with their test fluid (0 salinity) and use their test cal solution (1.026), I get 1.026 every time. When I use other test solutions (Pinpoint and Aquacraft) I get 1.028 every time. When I test my tank water (which has been brought up on a standard refractometer calibrated with the Pinpoint and Aquacraft solutions) I get 1.028.

I realize the stated accuracy is +/- 0.002, so it is technically within spec. And the repeatability seems spot on every time (although I haven't done a formal test).

It just seems weird that their test solution reads 1.026 and the others are 1.028. Their test solution does have a weird blue-ish tint to it...

Has anyone else has this experience?

I'll continue to use it and just shoot for 1.028, but it kinda irks me.

 

[cromag27]

Yes their test fluid has a blue tint. I would trust their kit more than pinpoint, etc. Just remember than once you open a bottle of any calibration solution, it starts to evaporate. Replace your fluid often.

 

[rck329]

Well, the Aquacraft cal solution is practically new so I don't any evaporation effects could be causing an issue. What makes you trust the Milwaukee fluid more than others?

 

[cromag27]

I've had inconsistent readings with pinpoint and aquacraft. Brand new bottles reading differently.

 

[rck329]

Just to follow up on this - cromag27, you were exactly right. I made a batch of homemade cal fluid from Randy's recipe. It read spot on 1.026. Pinpoint and Aquacraft went into the trash. Oh well.

I'm thinking homemade is the way to go and storing it in a tightly sealed glass container will probably preserve it's accuracy a little longer.

 

[ca1ore]

I actually think that precision is more important in most cases than absolute accuracy - as long as whatever it is isn't way off. Precision enables stability.