Ch test precipitate

[trivetman]

Joyful - thanks! That procedure worked. I still had some precipitate but much less and I could see the colors well.

If I wanted to do the 25ml sample how much extra r-0010 should i add at the start?

 

[JoyfulNoise]

For a 25mL Test sample you add 20 drops of R-0010 and 5 drops of R-0011L and then titrate. The sensitivity changes to 10ppm / drop.

 

[trivetman]

20 drops is the normal amount. How much extra should I add to deal with my high magnesium level?

The water volume is 2.5 x the 10ml sample but the regular instructions only call for 2x the r-0010. So ...I’m not sure how to scale the extra two drops I did with the 10ml test.

 

[JoyfulNoise]

You’ll have to play around with it a bit. Start with just 2X (24 drops) and see if you get similar results. If you had a pH meter, you could find the optimal drop count but it’s not really super important.

One other thing you can do is dilute your water sample. If you have an accurate beaker, you can mix 1 part pool water with one part distilled water (it has zero mineral hardness). Then you test as normal but double the result. If you have high Mg levels, the dilution will cut it in half.

 

[trivetman]

Thanks again. Ill give that a try!

 

[pwoodcl]

So try adding an additional 2 drops of R-0010 first (12 drops total) with no R-0012 added and then proceed with the test (3 drops of R-0011L then titrate with the R-0012). See if that helps.

Dissolved magnesium ions should precipitate out of solution as magnesium hydroxide at a pH of 10.5. That’s what the R-0010 does, it raises the pH of your sample. At a pH above 12.5, calcium will precipitate as calcium carbonate so you don’t want to raise the pH too high. My thought is that, for whatever reason, your pH is not getting high enough to cause the Mg precipitation and then, after adding R-0011L and a few drops of the R-0012, your pH goes up (because the R-0012 will raise pH slightly) and the Mg starts to precipitate (capturing some dye with it).

This technique helped me with my CH test and made the pink spec very tiny that I can see the blue color. Thanks for the tip!