Maintaining Free Chlorine!

[Mainer]

Hello Everyone,
I really hate to ask this common question, but I have no choice.  I am constantly struggling to maintain any chlorine at all in my Tahitian tub.  The dealer just can't get me straightened out. My water is about 2 months old.  Haven't checked TDS, but I'm quite sure I'm alright there.  Problem is I just can't keep a chlorine reading of any sorts in my tub.  Bought it last Sept. and have been fighting it ever since.  I do have a taylor kit.  PH is 7.4  Alk 90.  Two days ago I put 3oz. of Sani-Spa chlorine.  Had over 10ppm total chlorine immediatley,  free chlorine also 10, combined was 0.  Next day, 5ppm tc, 5ppm fc, and 0 cc.  Yesterday I tested and had nothing left.  What in the world is eating it up?  Only use the tub by myself maybe twice a week.  Any suggestions would be greatly appreciated.  Should ther  be a trace of FC [say 1-3 ppm] available at all times?  Thanks, Bill

[windsurfdog]

Did you have 0 cc yesterday?  Looks like you've got some contaminants in there and you have introduced enough chlorine to oxidize as it combines, hence the 0 cc readings.  Do you have an ozonator as well?  Has the tub ever been left without circulating water for a period of time?  Is the cover left off of the tub for extended periods in daylight?

[hottubdan]

I'm not an expert, but chlorine disappears over time.  If you added nothing over 3 days, plus you have the ozonator constantly oxidizing, it should be gone.  The only way to maintain free chlorine in a hot tub that I know of is to add it daily.

Most people with ozone don't worry about maintaining FC as long as they use some chlorine in conjunction with use.

Do you use Nature2 (Monarch cartridge)? :-?

[Steve]

1 person in a spa will use up 1ppm of chlorine every 15 minutes. The key is to shock after heavy use and weekly and add some after use to prevent a zero reading.

[Mainer]

Hey guys, Thanks for your comments.  Yes I did have a zero everything yesterday, and yes I do have an ozonator.  I guess the question that I can never get a straight answer for is " Am I supposed to ALWAYS show some form of CC or TC?  I don't leave my cover open for any length of time up here in Maine other than using the tub.  I do rinse my filter weekly.  I also change filters every 2 1/2 to 3 months.  Maybe I worry for nothing.  The water is crystal clear without odor.  I just can't get a straight answer on the amount of chlorine that I'm supposed to read daily.  Thought that this chemistry was supposed to be easy LOL.  Thanks alot, Bill

[hottubdan]

If you are not using daily you should not be testing daily.  Therefore, you should get no reading daily.

Even if you follow Steve's program you will end up with a reading of 0 a day or so after use.  I wouldn't worry about it.

[drewstar]

...  The water is crystal clear without odor.  I just can't get a straight answer on the amount of chlorine that I'm supposed to read daily.  Thought that this chemistry was supposed to be easy LOL.  Thanks alot, Bill

Crystal celar water and no ordor is a good sign.    

There are a few different  routines to using Chlorine (dichlor) and that may account for why you are not getting a straight answer.

I do not try to keep my chlorine levels up.  I dose to sanitize the tub and then let it go to 0.  What method did your dealer suggest?


Here's what  I do and it is similliar to what most people I speak with do...

I use dichlor and also have an ozinator.(O3)   I use my tub 2-3 times a week.   After each use, I add 1.5 teaspoons to my water and run the pumps for 10 minutes.  Experince has told me this raises the free chlorine to about 5 ppm.  This is good. It's enough to sanitize the water, but also drift down to 0 the next day.

I prefer not to soak in chlorinated water.

On off days I don't worry about adding chlorine to the water, the 03 keeps my tub clean. If I am
 away for more than a week, I'll add chlorine to 5ppm again and let it go to 0 again before using it.


Abotu every 10-15 days I shock with MPS.  I do water change outs every 4 months, and adjust for PH and ALK and CA on the "off days" that I am not dosing with the dichlor.

I don't think you need to try and keep the Chlorine constantly up.  Chlorine disapates quickly in the hot water. IF you wanted a continous sanitizer, bromine might be a better choice.

[windsurfdog]

I responded with a contaminants possibility because of the drastic decrease in ppm over 2 days.  If there are no contaminants, would it really be reasonable to expect ppm to drop from 10 to 0 in just 2 days?  I too have an ozonator and I use the MS mineral filters which I would equate to N2 cartridge use.  I've noticed that when I plan a trip away and have no one coming over to "chem-sit" the tub, that I usually have some fc or tc present upon return (maybe .5-2)...usually 3 days or longer...after bumping the ppm up to 10 or so before leaving.

[hottubdan]

I think Drewstar nailed it.

[Mainer]

I guess the outfit that sold me this Caldera really don't understand the chemistry.  They had told me to always maintain some Dichlor readings.  I think they said 1-3 ppm.  I have shocked occasionally with the MPS, adding about an ounce at a time.  Am I correct in saying that this gives you a false TC reading?  Drewstar, how much do you add when you use it?  Again thanks all,  I'll leave it alone now, Bill

[drewstar]

I guess the outfit that sold me this Caldera really don't understand the chemistry.  They had told me to always maintain some Dichlor readings.  I think they said 1-3 ppm.  I have shocked occasionally with the MPS, adding about an ounce at a time.  Am I correct in saying that this gives you a false TC reading?  Drewstar, how much do you add when you use it?  Again thanks all,  I'll leave it alone now, Bill

I'm treading on thin ice here, as I am not a chemist.   I cna't comment on what is giving you a false TC reading.
however, like you after I shocked with MPS I expected the shock to free up the CC and give me a boost of FC readings.  On my test strips, after shocking, I never saw it. Someone explained to me once why that was, and not to worry about it, but to be honest. I forget the reason what was going on, but it wasn't a concern.

Anyhow, it's been reported that you should always maintian a residual amount of sanitizer in your water.  That's a saftey statement. --  pool folks always run 3ppm in thier swiming pool (or should) this doesn't carry over to hot tubs. (Dichlor vs Trichlor and the intense heat and pools use feeders)  

Since you are running 03, you do have a sanitizer in your water.  Folks that don't have O3,  mght  have to add dichlor to thier water every 48 hours or the water goes to pot.   With the dichlor and the  O3, if you sanitize the tub after you use it, and no contaminets are introduced to the water ,  it will stay clean for a several days and as youve experienced...no problems.  

[Chad]

If one's tub has 0 FC,TC, and CC and you add a 10ppm dose of dichlor and don't soak at all, you should have some sort of residual after 3 days. Atleast that's the case in my tub, even w/o the N2 I've been using. With N2, I really don't know, haven't experimented yet. What is your CYA? It's probably 100ppm+ and causing you to add higher ppm dichlor doses to sanitze the same amount it was a month ago when your fill was still faily new. I know when my CYA gets above 100 ppm, it takes a significant amount more dichlor to sanitize my water. It makes the chlorine less productive as a sanitizer, thus taking more to do the same job.

[svspa]

Mainer,

You are getting a lot of good info here, but I'll step on my soapbox for a moment.

One reason people recommend a constant level of FC is that you have no other way of really confirming your tub is clean. Maintaining some level of FC allows you to see easily (with a simple dip of a test strip) that your tub is bacteria free.

Our more experienced members may have no problem letting their FC go to zero. I assume they have not had problems with anyone getting sick from their tub. They understand their water chemistry and they obviously don't have any sensitivity to anything that might be brewing. Not to say that bacteria will always exist in a tub with zero FC, I guess the question is if you can't measure the level of bacteria are you feelin' lucky?

Anytime I would recommend a routine for a spa newcomer I would recommend you want to keep some residual FC. Once you have your overall water chemistry under control you can experiment and make adjustments. At that point you will probably have a better understanding of your tub and the FC fluctuations versus your usage etc..

I would agree with windsurfdog and WHY NOT that 10ppm to 0ppm in 2 days is a big drop. If I raised my tub to 10ppm and didn't use it I would have residual FC for 5 days or more. I think that is a representation of the fact that there really is nothing in my tub needing to be killed and the drop is largely just natural dispersion over time.

Assuming you might be fighting something in your tub, personally I would continue to shock it with dichlor or raise your daily dose until you start seeing that residual stay around longer.

This is obviously a conservative approach, many folks seem to have happy, healthy tubs without being this conservative.

Steve

[drewstar]

Is it possible that he's shocking too much too often and that's why he's not seeing any TC change after the MPS shock?

[windsurfdog]

...after I shocked with MPS I expected the shock to free up the CC and give me a boost of FC readings.

Should one expect to get a boost to fc readings after shocking with MPS?  When the MPS chemically reacts with the contaminants, does it oxidize just the contaminant that is attached or "combined" with the chlorine molecule thereby "freeing" up the chlorine molecule to combine again or does it oxidize the entire chlorine/contaminant molecule/particle?  I was under the impression that it would oxidize the entire thing...but, like others have mentioned, I'm no chemist...although I did stay at a Holiday Inn Express last night...

BTW, we certainly would expect an increase in fc when shocking with dichlor...pretty obvious but I felt it worth mentioning in this context.