Measuring OPO / chlorine equivalents

[Gp!]

So I want to get a tester to verify how long I should go between changing the carbon after the ozone water output.

Per http://reefkeeping.com/issues/2006-04/rhf/index.php#16

This process can be monitored using a chlorine test, such as the Hach model CN-70, or one that works similarly but that reports results as ozone (e.g., the Hach model OZ-2).
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Hoping for a hanna checker for ease of use. I didn't see one that mentioned ozone. Would one of these work? If so which would be best?
- https://hannainst.com/hi701-free-chlorine.html
- https://hannainst.com/hi711-total-chlorine.html
- https://hannainst.com/hi761-total-chlorine-ulr.html

 

[Randy Holmes-Farley Verified Community Expert]

I’ve never used it, but the 761 looks like the best bet for this purpose. [emoji3]

 

[Gp!]

I’ve never used it, but the 761 looks like the best bet for this purpose. [emoji3]

Much appreciated!

 

[Gp!]

So I just spoke with Hanna tech support to verify the checker worked in salt water. They told me the test would not read correctly because calibration curve was set for fresh water. They said they did not offer a model that was set for salt water. And that was pretty much all they would say.

For this measurement however, I am not actually interested in testing for the exact quantity of chlorine equivalents in the water. I don't need an accurate reading as long as it is a consistent reading that is proportional to the actual amount. So in this case I am thinking that I can take a measurement of tank water as far as possible from the ozone output as a reference. And then take a reading exiting the ozone carbon filter. The difference between the two numbers should give me an indication of when the carbon starts to lose its effectiveness.

Is my line of thought correct? Or do I need to find a test that is set up for salt water. With a quick search none of the testers I found specifically stated they were for salt water.

 

[Randy Holmes-Farley Verified Community Expert]

I expect it is fine. They say they use an adaptation of a method that works. The comparison that you mention is what I did with a simple chlorine kit that uses the same method as the Hanna.

 

[Gp!]

I expect it is fine. They say they use an adaptation of a method that works. The comparison that you mention is what I did with a simple chlorine kit that uses the same method as the Hanna.

That works for me. Thanks for the clarification

 

[Muffin87]

@Gp! I'm having the exact same issue!

Which checker did you end up buying?

Were you able to check for residual ozone-produced oxidants in normal tank water using the hanna checker?

Did it also work to check the residual oxidants in the water exiting the carbon filter?

Thanks a lot!

 

[Gp!]

I got busy at the time and didn't. I've got the ozone equipment and am remodelling a new tank room now. I will be circling back to this soon

Please report back what works for you!