Still having trouble understanding chlorine...

[Garyjr]

I have read through and searched for the 1000's of chlorine topics from this forum as well as from rhtubs.  Still I am uncertain if I am going in the right direction with my tub.  I currently use about 1 teaspoon of chlorinating concentrate (99% sodium dichtoro) after each soak.  About once a week, my dealer told me to shock with 1 tablespoon of spa shock non-chlorine (31% potassium peroxymonosulfate, 69% other ingredients) and 1 tablespoon of the chlorinating concentrate (99% sodium dichtoro.)
I shocked the tub after our soakl last night, and just pulled a water sample.  According to my Taylor tester, I have 5 ppm of FC and 5 ppm of TC.  So, I am assuming that my CC is 0.  
I soaked this morning and noticed that my skin felt extremely dry when getting out, and also noticed that a small amount of "scum" had formed around the edges of the tub overnight.
With all other levels being in check, I am thinking the dry skin and scum had to of came from the FC and TC being a little higher than it should be.
What steps do I need to perform to get my FC and TC back down in the 2-3ppm range?
If this helps, we have a SunDance Maxxus which holds right at 500 gallons of water, and I just did a water change about 4 days ago.

Thanks for all the help,
Jr

[lskarp]

I am a user, not a tech.  But I think i may have to do with the high concentration of Chlorine in the solution you are using vs the amount you are putting in.  I have a 500 gallon spa (Vita Nuage).  After soak, I use 1 tsp of 56% Diclor.  Once a week, I shock using 2 TBS of Diclor, and 2 TBS of MPS (non-chlorine shock).  My levels seem to be consistent and the water 'feels' great.  I also use N2, which I am not too sure that it saves much in the chem side of the equation, but the dealer told me to use it and I like my results so far, so I ain't changing it.  I think they call this system here 'the vermonter' after the person who posted.  It does line right up with my dealer recommendations and the brochure from Leisure Time (the company that makes the chems I use).

Good luck!!

[windsurfdog]

The easiest way to let chlorine drop is to open the cover and let the sun shine in!  Sunlight breaks down the dichlor rather efficiently.  Or just take a soak after mowing the grass and getting all sweaty thereby providing lots of nasties for the chlorine to work on...  But I suggest the first method... 8-)

[Dr. Spa™ Ret.]

You're getting confused on percentages. While the chlorine might CONTAIN 99% chlorine, that's NOT the AVAILABLE chlorine. The AVAILABLE chlorine is what's condisered when you talk about the strength of the chlorine. The HIGHEST "AVAILABLE" chlorine in sodium dichlor is 62% with 56% being more common (hence, "Spa 56")

Spa Essential's Chlorinating Concentrate is also 56% AVAILABLE chlorine.

No assumption necessary. TC - FC = CC ........... you have no combines chlorine

[Bill_Stevenson]

Test for total hardness.  If it is below 150 ppm or so, add some calcium hardness and that should take care of the scum.

Bill

[hottub.pool_boy]

You now have WAAAYYY to much information. Sensory overload! REBOOT!

[Garyjr]

I knew I would receive tons of GREAT feedback on this, and thanks to all for the replies.  So being that my FC and TC are both at 5, and my CC would equate to 0, should I add non-chlorinated shock to finish freeing up the TC, or should I leave it as is until the levels comes down below 3ppm?

[Vinny]

Gary,

It's my opinion if using a drop testor (taylor kit) that you can't accurately tell the TC vs FC unless the FC=0.

I don't think I'm color blind but if your CC = 0.5 to 1 you might not be able to tell if you FC = 5.

I can't help if your using test strips but my opinion of them is don't use them!

[hottub.pool_boy]

Leave it alone with the non-chlorine shock. 5ppm is fine to soak. We actually recommend the test strips. They're quick, accurate(as needed), and tell you if you have free available chlorine (all you really need to know). Yes, there's lots of chemistry if you'd like to learn it, but why.

[Vinny]

Leave it alone with the non-chlorine shock. 5ppm is fine to soak. We actually recommend the test strips. They're quick, accurate(as needed), and tell you if you have free available chlorine (all you really need to know). Yes, there's lots of chemistry if you'd like to learn it, but why.

Are you saying you can't count to 2, 5, 10 or 20? What are they teaching kids these days!

Fill vial up to 9 ml, add 5 drops of R001 (I usually cap the vial and mix the chem but that's me) add 5 drops of R002, cap vial and mix - put against white background and take your reading; now take R003 add 5 drops to vial, cap and mix - put against white background and take your reading.  The difference is the combined chlorine ...THANK GOD I went for Electrical Engineering, I guess I would be able to handle it otherwise!

The test strip I saw said Good , OK and Low - Not a warm fuzzy feeling ... is good in PH 7.2 or that OK OK-Good=? (or is it good - OK=?)

Sorry, I am a tech and am precise - that's me. I don't understand how anybody testing anything can have it just good enough. I drive many companies crazy because something has a 5% tolerance and I'll fail it at 5.1%. I'm trained to be precise and that's why the Taylor kit is the way to go IMO.

[Gomboman]

Go to the FAQ section and read "What is the "Dichlor Dosing - Vermonter Style" at:

http://www.rhtubs.com/cgi-bin/bbs/config.pl

[Garyjr]

Thanks for all the great replies.  
Vinny- the way you described is exactly how I am testing with my Taylor kit.  The question I still have is with readings of 5ppm TC and 5ppm of FC, should I be adding anything other than my usual dosage of chlorine concentrate following a soak?  In other words, is it ok to have 0 CC?

Once again, thanks to all for providing a great forum to share information.

Jr

[In Canada eh]

 In other words, is it ok to have 0 CC?

Gary,

Zero combined chlorine is exactly the way you want it.  It is when the combined chlorine begins to climb that you should shock.  Y ou can shock your tub on a schedule (every Thursday) or you can test for combined chlorine and shock only as needed.

I personally shock the tub every Thursday evening but thats just my routine

[Garyjr]

Thanks In_Canada_eh.  And thanks to everyone else who posted as well.......

[The_real_Clown_Shoes]

5 ppm Chlorine is perfect.