Jump to content

DPD water testing help- Bromine DPD-1 vs DPD-4 trying for low level safe bromine.


qbquixote

Recommended Posts

We have a little 210 gallon marquis set up now for 2 months in a 3 season room.  Inline spa frog mineral, bromine and ozone.

I use three step bromine with the inline frog cartridges.  (though when I get through my current pack of cartridges I might start filling them with tabs those cartridges are expensive)

My tests kit is a colormeteric DPD test and recommends DPD-4 for bromine.   It has measured reagent on little strips.  I have  about 100 strips left and bought the kit before finding out about the love of Taylor titration tests on this forum.  My kit DPD-4 generally tests higher than the pool store.  If I use the DPD-1 chorine test strips and multiply by 2.25 it tests spot on with the pool store.

I use MPS and have recently turned down the spafrog cartridge and throw in a little mps after each use.  We had developed a strong "bromine smell"- posted about earlier and it has gotten a lot better targeting the lower dpd-4 number between 2 and 3 ppm.  Previously I used less a lot less MPS and higher setting cartridge bromine, and did not put any oxidizer in after use -- just a couple times a week and we use the spa most days.

Now the DPD-1 number is below 1 most days and I am nervous I am running the bromine too low for good santitation.  I am not sure what the other oxidizers are since MPS is supposed to quickly convert my bromide bank and my ozone is runs intermittently and is supposed be gone in 30 seconds.

Most threads I have found say it does not matter whether I use DPD-1  or DPD-4 since DPD-4 just measures other oxidizers too.

The numbers are consistently different and I am trying to go as low as is safe to minimize smell and irritation in the tub.  Any advice?

Thanks

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...