Knop C/pH controller setup

[hllywd]

I undersand the basic reactor setup and theory but not sure what the controller does for me. Where do I plumb it in the system? Am I controlling the effluent, the loop or the system pH (or are there different ways). I have 1 guy I can goto for the reactor setup but he doesn't use a controller so any help I can get here would be appreciated.

TIA,
Tim

[Henry Bowman]

I use 2 probes in my system with a controller to adjust the reactor. The probe in the Ca reactor is just there to give me constant readings (some folks measure the effluent to get the same reading). I adjust the reactor so that the reactor pH is about 6.5 and keeping up with the calcium demand of the system. The other probe I use is in the sump and I use it to control the solenoid (sp). If my tank pH drops below 7.9 it shuts the reactor off.

In the end I believe that it is best to get the reactor tuned to the system and use the pH controler as a stop gap to keep it from driving the tank pH down too far.

Some folks just use the controler to shut off the co2 to the reactor instead of getting the reactor dialed in correctly. (If pH in the reactor gets too low, the media turns to mush, if it is too high- the reactor doesnt add Ca...). I believe that this thought process makes adjusting the reactor down the road very difficult as demand for Ca increases.

In addition..... I calibrate my probes differently. I use pH4 and 7 to calibrate the Ca reactor probe since the values are closer to where the reactor is running. Then I use 7&10 to calibrate the tank probe for the same reason. Moving a single probe back and fourth "could" create more inaccuracy in the readings.

I would use the probe in the tank the same way I do and measure the reactor effluent as you are setting up.

Have you looked at the reactor information in the RC Chemistry Forum. It's under the articles section. Jdiek wrote the program and information. It is very helpful.

Dont mean to ramble but I have found this method to be pretty reliable.

[hllywd]

Thanks Harry,

Your info mostly confirms what I suspected. I appreciate your response and will check out the chemistry forum. The two different probes explains why I've seen a couple different readings on others' systems where I wasn't able to get immediate explainations or didn't fully comprehend the ones I got, I've seen in the neighborhood of 6.3-6.5 and also 8.2-8.4 they were all single probe systems I believe.

Thanks again,
Tim