using a pH probe to monitor Alk.

[jcraft]

How would I go about using my pH monitor to calculate Alkalinity?

In a previous thread about test kits and colorblindness, I was told there is a way to do it . . .

do the test kit like normal and put the probe in the solution? what value am i aiming for?

 

[RobbyG]

Is this a trick question LOL

 

[jcraft]

<a href=showthread.php?s=&postid=6567774#post6567774 target=_blank>Originally posted</a> by RobbyG
Is this a trick question LOL

i dont think so

in a previous thread, I was informed that even though Alkalinity is measured by titration, you could use a pH probe to get the results you want if you cant use the kits (i.e. colorblind)

i just need to know the process

 

[Morgandy]

I would LOVE to know this answer, but I didn't think it's possible. My pH is 8.2 / 8.3 and the alk has been way low. The d**n kits make me nuts.

 

[bertoni]

Hmm, I suppose you could measure the pH of the titration sample with a meter to determine when the endpoint has been reached. I think that should be around pH 4.2, but I'm not sure that the endpoint really should be the same for all kits, so you might want to "calibrate" the endpoint by having a friend do a few tests for you to see what pH causes the color change.

I think the real moderator should be able to help more.

 

[bertoni]

http://www.reefcentral.com/forums/showthread.php?s=&threadid=635056&highlight=titration+alkalinity

Finally found that thread.

 

[Randy Holmes-Farley]

:thumbsup:

Yes. pH 4.2 it is.

do the test kit like normal and put the probe in the solution? what value am i aiming for?

If you want you can use a normal kit, and use the pH meter instead of the colored indicator endpoint. Without a kit, you need a standard acid solution. I show such pH titrations to determine alkalinity in this article:

What is Alkalinity
http://www.advancedaquarist.com/issues/feb2002/chemistry.htm