New TF-100 user, where is my chlorine not going?

[Verne Bunsen]

Hi all,

A couple of weeks ago I had a thread going about getting my SWG properly configured after having just converted to saltwater. The TF-100 test kit was recommended and I ordered it immediately. I went out of town for a while and got back this last Friday 11/9. I took a set of readings and this is what I came up with:

FC-11
CC-0
pH-8.2
TA-190
CH-470
CYA-70

I know that chlorine readings are sketchy with high pH, so I've been working on getting that down. I also turned off the SWG to allow the chlorine level to drop. My pH is now 7.8, I'm still working to get it down to 7.2. I think my pool may be bigger than I think, as the recommended MA treatments don't do near what is predicted... The interesting thing is that I did another drop test on the chlorine level today (Monday 11/12), after 3 days of running with the SWG off, and it is still 11! I'm in Arizona, so the pool is definitely seeing the sun, although we haven't been swimming in a while. Is this just a coincidence from the pH coming down and affecting the test results, or is there something weird going on? I conducted the drop test twice both times and got the same results.

Thanks!

And PS - The TF-100 is awesome!

 

[duraleigh]

I know that chlorine readings are sketchy with high pH

Actually, it's pH readings that cannot be relied upon when chlorine is high. (usually around 10ppm or higher.)

With a CYA of 70ppm and little bather load, your FC will come down pretty slow but keep the faith, it will come down.

Once your FC gets to around 4-5ppm (normal maintenance level) Your pH may read back in the 7's, too. It is not necessary to lower pH all the way down to 7.2 but test pH again after your FC drops below 10ppm and then lower it (pH) down to around 7.4 - 7.6

 

[dmanb2b]

I think my pool may be bigger than I think, as the recommended MA treatments don't do near what is predicted...

Also double check the MA concetration (%Baume) you are using.

 

[Verne Bunsen]

Actually, it's pH readings that cannot be relied upon when chlorine is high.

Ah, an important distinction, haha! Thanks for setting me straight! I guess best course of action will be to just let it go for a bit.

Also double check the MA concetration (%Baume) you are using.

Good thought. I checked it and it's 31.45% HCl, same as what the test kit calls for. I'll leave it be for a while and see where it lands when the Cl gets back in line.

Is it alright to swim at 11ppm Cl? If the Cl is this slow to come down from 11, how long would it take to come down from shock levels?!

Thanks for the input!

 

[jblizzle]

Hello neighbor.

It is safe to swim up to shock FC levels ... for 70 ppm of CYA, according to the chart in Pool School you are fine to swim up to a FC level of 28ppm. It would drop a lot faster if you threw some fertilizer in the pool, but that is not really a good idea Just a function of organic load and sun exposure ... it takes as long as it takes.

I have given up on swimming this year ... without a cover, even the large solar array I have added is not helping much ... certainly with the lows temps in the 40s.

 

[Verne Bunsen]

Yeah, I think under normal circumstances I would have given up on the pool for the year myself. However, my mother-in-law is coming down from Alaska (where we just moved down from) in a few days, so I'm heating the pool to a nice 80 degrees with the gas heater so she can luxuriate for a bit A scary gas bill is a good trade for a happy mother-in-law, haha! And of course, the hot tub will never go out of style.....