Why the heck wont my Chlorine level drop?

[dkersten]

I have had my tub for about 5 months now, and I have not changed anything in my regimen since day one.  After each soak, I add about 2 teaspoons of di-chlor.  For the first 4 months, after about 20 hours, the free chlorine level would pretty much not read at all on test strips.  BTW its a Tiger River with the silver ion and the ozonator.

I changed the water about a month ago (5 weeks I think) and my ph and alk levels are normal, although my alk is starting to creep above the ph, which I learned tends to happen as you get closer to time to change the water.  So far, both ph and alk are still in the normal range (at least as accurate as those test strips are).  

The problem is, I put in 2 teaspoons of di-chlor last week, and the next day the chlorine was really irritating my eyes.  This is about 22 hours after adding chlorine.  Now like I said, it used to be that after about 20 hours chlorine level was pretty close to zero.  I was concerned, so I checked it, and sure enough it was a solid 10ppm.  So I figured I didnt need to add any since it was high still.  The next night, the water still stunk of chlorine a little, which is noticeable because I am not used to it.  It was about 3ppm, so I added a teaspoon of dichlor.  The next night was about the same, but it had been a week since I shocked, so I checked my ph and alk levels and they were normal so I didn my usual shock procedure.  I added the activator, about 7 teaspoons of chlorine, and some protect plus.  I usually run it for 30 minutes with top off, then another 10 with top closed after a shock.  Next day, about 24 hours later, I read about 8-10ppm of chlorine.  I figured this wasnt bad since I had shocked the night before and usually it takes a little longer for the chlorine to dissipate.  Then last night, I got in and noticed it still had a strong chlorine smell and my eyes were burning after I got out.  I checked and still had about 4 ppm chlorine.. this is 48 hours after a shock with no other chems added since.

Now, when I was close to the end of my water life the first time, I saw similar results, but after the water change chlorine would be almost zero after 24 hours.  Now here it is barely a month after a full water change and 2 teaspoons of chlorine to 330 gallons of water will stay over 3ppm for over 48 hours.  

What the heck is going on?

BTW, the only thing I have been doing different is I will now open half the cover, and then run the jets on full for about 20 mins before getting in.  For some reason, if I dont do this, my temp will be usually 1-2 degrees below where I have it set (103).  By running the pumps, I guess the heater is kicking in and getting the water up to temp, and the soak is much better.  I cant see why running the jets longer with the top off would make the water retain the chlorine for a longer period, but I am not an expert  

[dkersten]

I think I will be reducing the amount I use, but like I said, I have followed this regimen for 5 months and only recently has it become an issue.. I dont ever recall getting a zero reading on a test strip for chlorine, but just a slight purple is what I am used to after 24 hours, and from the few times I have tested AFTER putting chlorine in, 2 teaspoons usually yields about 4-5 ppm.

My dealer, who has been in business here a long time and is very well respected, insists on no less than 2 teaspoons per day if you use the tub.  

I am actually starting to wonder if my latest bottle of di-chlor has some super high concentration chlorine in it..

[dkersten]

Oh, I have not cleaned the filter since the water change 5 weeks ago.. I was going to do that this weekend as I missed it the last couple weeks.. But I cant imagine 5 weeks of not cleaning out the filter would cause the chlorine to not dissipate..

[tony]

My tub holds 485 gallons of water and I use about one tsp per person after use.  That will get me to about 2ppm which is just where I like to be.  24 hours later I should be just about zero.  Once per week I add one tablespn to get me to 3-5ppm.  This is not a shock, just a weekly spike because I like to use a minimal amount during my normal use.

[Tatooed_Lady]

dk, if it counts for anything (and it probably doesn't), I use dichlor after we use the tub (bromine's gone at this point, and I need to get to the store for more), and with a 500 gallon Grandee, 2 people using and sweating in it for around 30-40 minutes at a time, I add in the neighborhood of 2-3 tsp of dichlor. I've been slacking on testing EVERY time we use the tub, but that amount keeps it clear, doesn't stink, and still allows me to shock the tar out of it and have things come back to normal.
I'm NOT a pro (don't even play one on TV, sorry), but it DOES sound like overkill for the amount of water you've got in your tub...I guess, though, that it all depends on what your water balance is like, how new/old it is, what kind of crud is in the plumbing (if any), how clean/dirty the tub users are, if there's lotion/hair goo/etc involved, etc. There ARE a lot of variables, but the good guys on here seem to know what they're talking about. Give it a shot using less dichlor for a couple days, see how things work for you...worse comes to worst, there's always a drain/refill available to let you start over, but I seriously doubt it would come to that.
Clean filters, well balanced water that's not too 'old', and a chemical routine you can live with.
Good luck!!

[hottubdan]

Watkins recommends 1/2 teaspoon chlorine per 250 gallons if using silver ion system.

[Reese]

...After each soak, I add about 2 teaspoons of di-chlor...The problem is, I put in 2 teaspoons of di-chlor last week, and the next day the chlorine was really irritating my eyes.  ...The next night, the water still stunk of chlorine a little, which is noticeable because I am not used to it...it had been a week since I shocked,...so I didn my usual shock procedure.  I added the activator, about 7 teaspoons of chlorine, and some protect plus. ...Then last night, I got in and noticed it still had a strong chlorine smell and my eyes were burning after I got out.  2 teaspoons of chlorine to 330 gallons of water will stay over 3ppm for over 48 hours.  

You may be a little heavy on the dichlor, but 2 tsp in 330 gal is about 5 ppm, not that bad.  1-1.5 tsp may be a better dose.  Given your description, I'm wondering if your shock dose was inadequate.  Free chlorine really shouldn't smell or hurt your eyes, but combined chlorine does.  Do your test strips measure free, or total chlorine, or both? A dichlor shock needs to be 10X the amount of CC or it actually adds to the problem.  If you have had 5 weeks of inadequate shocks, your CC levels could be quite high.  If you can't measure CC, 5-7X your daily dose is a rule of thumb for a shock dose.  Since you were dosing 2 tsp, that would equate to a 3-4 Tablespoon shock, about twice what you were doing.  That is a lot of dichlor, so perhaps a MPS shock would be a better choice.  You mentioned "activator".  Is that a non-chlorine shock?  If so, try shocking with that, at the rate recommended on the bottle.

[In Canada eh]

 Given your description, I'm wondering if your shock dose was inadequate.  Free chlorine really shouldn't smell or hurt your eyes, but combined chlorine does.

dkersten,

    Reese is right free chlorine should not give off an odor,  combined chlorine will give off the musty chlorine odor you are probably smelling.   My advise would be to shock the poop out of your tub as Reese has said.

   Vinny (our resident chemical expert may have some other suggestions if you can wait for him to chime in

[Chad]

Spaguard chlorine concentrate is 57% AVAILABLE CHLORINE. If you go to bioguard.com, you can see for yourself.

[Chad]

 
Now, when I was close to the end of my water life the first time, I saw similar results, but after the water change chlorine would be almost zero after 24 hours.  Now here it is barely a month after a full water change and 2 teaspoons of chlorine to 330 gallons of water will stay over 3ppm for over 48 hours.  

What the heck is going on?

It may sound gross but someone told me this before.(I forgot who it was, but it was someone here)
Someone who uses a hot tub regularly is cleaner than someone who doesn't. It cleans out your pores or something. :-? Maybe since you've been soaking for awhile now, your finally "spa clean"  thus enabling you to use less sanitizer.

[Chad]

Btw, my tub is 336 gallons and 2 tsp usually brings it from a 0 FC to a 5-8 FC 20 minutes after dosing.(depends on how new my water is) Most of the time some chlorine was still present 48 hrs later in the first month or so of my fill. It definetly has been going quicker now that I'm into my third month of the same water. I don't fully understand why it happens but I know it is happening in my water. Maybe an expert will chime in and help me understand why.

[Chad]

1.)No where on my Chlorinating Concentrate bottle does it say 55% Available Chlorine
It says Active Ingredient - Dichlor 99%
           Other ingredient 1%

2.) No where on the spaguard or bioguard web pages could i find 57% available chlorine.

So, If you can find the link that this on the web pages, I would appreciate that you send it to me. I could not find it.

I don't know how to do the clickable link thing but here it is the old fashion way.

www.bioguard.com/msds/docs/142046.pdf

[Chad]

 :-? :-? :-?

Did you go to the link?

[Vinny]

Thanks for the compliments of being an expert but I am no where nearly as educated as Vermonter in this area, but I bet he's not as geeky as I am ... I love science and math.

Every so often my tub retains chlorine for long periods of time - chlorine lock. I can add 3 PPM and it will stay for 3 or 4 days. Bonibelle has brought to my attention that phosphates can cause chlorine to last for long periods and I've read that if you use MPS (non chlorine shock) that it will raise the phosphate level which is why you shouldn't use it in an outdoor pool - phosphate is an algea food. And I used MPS to shock before this happened this year.

I am also contemplating that water companies do something different to their winter water than to their summer water (like Sam Adams Winter Brew and Summer Brew) and it affects the water (at least my water).

Unless you have VERY high, 15 or more PPM, you probably will not smell chlorine. I have only had that smell twice - once when I had chlorine lock and soaked in 20+ PPM chlorine and once when my combined chlorine was high. If you are sure (I do not like test strips - sorry) that there is only 3 to 6 PPM chlorine then the smell has to be coming from combined chlorine and a good shock will take care of it. I personally would use MPS which might contribute to the chlorine lock "problem" - see below.

I would suggest looking at what you have shocked with and see if anything has MPS in it. I also wouldn't stress out about it - I did that last year when it happened but this year I look at it as being a good thing ... put in 3 PPM and for a week I don't have to worry about bacteria. Sounds stupid but in my observation I would say that nothing is growing in the tub as long as the chlorine is present.

Now for chlorine, it depending on the available chlorine in the product you use as to how much you need to add. If it's 52% you need more product than at 62%. For me with 400 gallons - 1 teaspoon of 62% equals approximately 1.5 PPM so with a smaller tub using the same % of available chlorine you should be at 2 or even 3 if your tub is below 300 gallons ... remember that if you're around 3 20 minutes after adding it - you've done the job that the chlorine needs to do. I was keeping my tub at 1.5 PPM for months and had a residue in the morning after using it and my tub was crystal clear BUT once I had high PH and it didn't do the job (lower PH = greater chlorine killing power) so I decided to up it to 3 PPM and not have to worry.

For anyone who cares - The amount of chlorine in a given product is the available amount of chlorine - most dichlor chlorine is in the 52% to 62% available amount range and most dichlor is between 97% to 99% active ingredient - 2 totally different figures and can be a confusing concept. When shopping for dichlor as in everthing else look for the active available chlorine and look at the price ... if your going to pay $16 for 2 lbs of 62% or $14 for 2 lbs of 52% ... you have to figure which is the better bargin ...

[Chad]

 if your going to pay $16 for 2 lbs of 62% or $14 for 2 lbs of 52% ... you have to figure which is the better bargin ...

If my math skills serve me right, the 16/2/62 is the better deal. :-?