Sanitizer Dosing Procedures

[akm]

Greetings...

Looking to apply the dichlor then bleach method to sanitizing my tub, and have a couple silly questions with regard to actually accomplishing this the right way.

Right now, I'm sprinkling in the dichlor (still in the dichlor phase of start-up) granules into the filter compartment slowly after a soak, and setting the tub on a 10-minute "clean cycle".  After this finishes, I'll go back out and close the lid.

When I switch to bleach, should I also be adding this slowly into the filter compartment? Into the middle of the tub? Somewhere else? 
Should I dilute the bleach first in a bucket of spa water then pour it in (to either the filter compartment or middle of the tub)? 
Am I over-thinking this too much, lol?

Also, can these sanitizer doses (either dichlor or bleach) be applied after a soak with the clean cycle on and then close the lid and head in?  I don't mind coming back out for a minute to pop the cover back on, but when it starts snowing I might change my tune.  It would be super nice if I could hop out, add the bleach/dichlor, hit the clean cycle and close the lid. 

Is it ok to run a clean cycle with the lid closed?
Is it ok to run a clean cycle after dosing with sanitized with the lid closed?

I know you don't want to add a ton of chemicals and close the lid (after shocking for instance) because it could hurt the cover, which I obviously don't want.  Just trying to build the right habits out of the gate.

Thanks!

[chem geek]

Usually Dichlor dissolves quickly enough that you can add it to the tub with the circulation running.  You generally don't want to add chemicals into the filter compartment (adding acid there is a definite no-no).  You should be able to add the bleach to the spa water directly since it will dilute very quickly if circulation is running.

You normally dose after your soak with enough so that you still get a 1-2 ppm FC residual for the start of your next soak.  If you aren't soaking every day or two, then you may need to add more chlorine in between soaks (especially if you have an ozonator since ozone consumes chlorine).  Most people don't dose enough because they have higher bather-loads.  If you have no ozonator, then a rough rule-of-thumb is that every person-hour of soaking requires 3-1/2 teaspoons of Dichlor, 3-1/2 fluid ounces of 8.25% bleach, or 7 teaspoons of non-chlorine shock (43% MPS) where the latter is for the Nature2 system unless you are splitting your oxidizing doses with a mix of chlorine and MPS.

After you add chlorine to the spa after your soak, you should leave the cover off for a while to allow for outgassing of the most volatile compounds.  Most of the oxidation of your bather waste occurs in the first hour so keeping the cover off even for a short time will help extend the life of your cover.  Also, just before your soak, you should take the cover off and let the spa air out for a few minutes (perhaps briefly running the jets).

Don't forget that with the Dichlor-then-bleach method you need to have your TA low at around 50 ppm and have 50 ppm Borates in the water by the time you switch to using bleach.  This is because Dichlor is net acidic while bleach is not so you need a lower TA to reduce the rate of carbon dioxide outgassing that increases the pH and you need the borates for additional pH buffering given the lower TA.

[Vinny]

I typically throw either the dichlor or bleach toward the center of the tub with all the jets running to mix it up. Run Jets for about 5 minutes (reg dose) or 20 minutes (shock) and then close the cover. Dichlor is a lot easier since it's granular but I do pour the bleach into the tub at about arm's (elbow) length. I tend not to use bleach too often as it is much easier to use granular products then liquid, bleach will loose potency if left in heat and sunlight and my laundry is in the basement ... far enough away from the tub. My suggestion is to have the bleach premeasured and ready to go when you do start to use it.

Once the initial off gassing occurs (5 minutes) you can close the cover while it is still in clean mode. Typically I am the one adding sanitizer to the tub so once I get out - I turn on pumps (clean cycle?), throw in chlorine, dry off - you'll be amazed how long you'll feel warm in the winter once you have sat in hot water for a while, put robe on, de suit, depending on chlorine dose either turn off pumps or go inside until the time is up and then close the cover. I do try to shock on the weekend so I am usually just closing the cover after the 5 minutes. I have an enclosed screen room right next to the tub so if it's rainy or snowing it isn't quite as bad as being out in the open ... of course when it's winter and it's windy - it is horrible to be wet and have the wind go through you.

I think you can just hop out with bromine and close the lid as combined bromine is still an effective sanitizer; combined chlorine is not.

[Vinny]

Something I want to say about chlorine dosing and I'm sure that Chem Geek's info is more accurate than mine but I have been using my tub without problems for 9 years now.

I typically shoot for 3 PPM when I've used the tub by myself, shoot for 4 1/2 PPM with one additional person and 6 PPM if there are 3 or more. If there is a party where the tub is being used then I will dose before, during and after the tub is used. Saying this my tub is 400 gallons and I know that for the dichlor I use I need 2 teaspoons for 3PPM, 3 for 4 1/2 PPM and 4 for 6 PPM which is a little (a lot?) less then the amounts Chem Geek is quoting.  I have gone 2 or 3 days between doses and have had a slight chlorine residue <1 PPM and still used my tub - having free chlorine means that the chlorine wasn't used by anything and wasn't burned off by the heat. If I've gone a while since I've added chlorine (4 or 5 days) then I will add 1 teaspoon into the tub before getting in. If I've gone an appreciable amount of time without adding chlorine I will shock with 10 PPM chlorine to get the extra killing power.

Like I said I also have used bleach; the website that I learned to use it from was (is) a pool forum. Back then it was said to use bleach, borax and baking soda for pool chemicals and I have used them for hot tub chemicals. The info about the 50 PPM borates and low TA is a new concept for me and I use bleach for chlorine just as I use dichlor with great success but infrequently - I am not saying Chem Geek is wrong but I have only noticed my water once having very high PH and that was after filling my tub, using baking soda and also using bleach .... which may be what Chem Geek said was going on.

The one thing to be aware of is that bacteria is not the same as algae - other than a biofilm it can be killed rather easily by chlorine.

[Topline Mike]

Vinny, if you're using more dichlor than bleach, do you have any idea of what your CYA (cyanuric acid) level is in your hot tub? 

I add my chemicals to the center of my tub with the pumps running.  I will say that my cover may deteriorate sooner than later because when it's cold outside, I don't want to stand around after I add bleach to let it circulate.  I like to add the bleach, shut the cover, and get inside.  I generally add about 2-3 ounces of bleach after I get out.  I use a 1 ounce shot glass as my measuring tool. 

[Vinny]

I'm sure that by the end of the water's life we're talking probably 100 + PPM. Soaking 3times a week at 3ppm x 12 weeks = (9x12 = 108) add a few 10 PPM shocks in there and you get 148 PPM chlorine so about the same in stabilizer.

You have to remember that using bleach in a hot tub is a "new" concept. For years people only used dichlor in their tub for chlorine.

[akm]

Great info guys. Interesting because my manual (Hotsprings Envoy) says to categorically add ALL chemicals to the filter compartment.

Sounds like a good rule is to add chems to the middle with the clean cycle on and leave the cover off for at least 5 minutes before buttoning it up (clean cycle may still be running when cover goes on). This seems reasonable so let me know if I'm blundering hard.

I also definitely added some dry acid into my filter compartment (as well as calcium, boric acid, and dichlor). Don't tell anyone

My TA at 70 seems to have kept my pH stable at 7.6 and doesn't appear to be climbing from aeration any longer. Will keep an eye out when bleach time starts and assume I may need to bring it down a bit further with dry acid.

Thanks again all!

[TwinCitiesHotSpring]

I'm sure that by the end of the water's life we're talking probably 100 + PPM. Soaking 3times a week at 3ppm x 12 weeks = (9x12 = 108) add a few 10 PPM shocks in there and you get 148 PPM chlorine so about the same in stabilizer.

You have to remember that using bleach in a hot tub is a "new" concept. For years people only used dichlor in their tub for chlorine.

def. not new, I've had customers doing it for 15-20 years...its just not too "common" because nobody who works in a retail environment is going to recommend pouring in straight bleach into a new hot tub, not because it doesn't work or anything like that, its just hard enough convincing people that chlorine is completely safe and harmless...you could imagine reactions when telling them to pour in straight bleach..lol

[Vinny]

I'm sure that by the end of the water's life we're talking probably 100 + PPM. Soaking 3times a week at 3ppm x 12 weeks = (9x12 = 108) add a few 10 PPM shocks in there and you get 148 PPM chlorine so about the same in stabilizer.

You have to remember that using bleach in a hot tub is a "new" concept. For years people only used dichlor in their tub for chlorine.

def. not new, I've had customers doing it for 15-20 years...its just not too "common" because nobody who works in a retail environment is going to recommend pouring in straight bleach into a new hot tub, not because it doesn't work or anything like that, its just hard enough convincing people that chlorine is completely safe and harmless...you could imagine reactions when telling them to pour in straight bleach..lol

Interesting ... I know of Chem Geek from another site (actually another 2 sites) and one day years ago he showed up here and there was a lot of pushback from the regulars on here then about using bleach. I have perfected (if you can call it that) my pool water chemistry so I stopped going the sites and use the Bleach, Borax and Baking Soda routine. Then I wanted a tub went to another site, learned some stuff there and it started to dwindle in posts and found here. Since my hot water didn't behave like my cold water I needed help again ... The discussions about dichlor, bromine, Nature 2, spa frog, full foam vs thermopane,  ... were all the rage  No Bleach or Borax discussions here! As I mentioned in some recent posts I kind of remember reading somewhere that using bleach will void your warranty.

Because I left the pool forums, I missed the findings about 50 PPM borates, low TA, Boriatic acid and the like; what I use works for me and has for some years. If bleach was more convenient I would use it more often but it is SO easy to open a jug and toss in teaspoons of granular stuff.

[chem geek]

Well if you want the benefits of not continuing to raise the CYA level and you want something granular without side effects (no rising CH either), then there is lithium hypochlorite, but it is very expensive.

Vinny, I think you don't have as many problems with rising pH because you are using enough Dichlor and it is net acidic because though Dichlor is pretty pH neutral upon addition, the consumption/usage of chlorine is acidic.  With bleach or any other hypochlorite source of chlorine, the pH rises upon addition and then drops again as it gets used/consumed.  It's carbon dioxide outgassing that has the pH rise over time and that is minimized by lowering the TA level.  The Borates are there to substitute as a pH buffer since the lower TA level would have less pH buffering.  Basically, TA is a mostly a measure of the over-carbonation of the water (it mostly measures bicarbonate).

As for using bleach initially, that's a bad idea because without CYA in the water the chlorine will be too strong, will outgas too quickly so will drop faster and harm covers faster, will oxidize swimsuits skin and hair faster, will corrode equipment faster, will create disinfection by-products faster, etc.  You want some CYA in the water, but don't want it to get too high.  Getting to 100 ppm CYA is probably not a problem, but I recommend around 40 ppm CYA as a decent target.  The main reason I started recommending Dichlor-then-bleach was after tracking dozens of hot tub itch/rash/lung incidents on another forum and then correlating them with potential causes.  While the number one reason was a lack of sufficient disinfectant (including use of "alternative" methods that weren't really disinfectants), the second reason was Dichlor-only use in higher bather-load situations that built up the CYA level where problems mostly occurred at around 200 ppm CYA though possibly somewhere above 100 ppm CYA.

People have found that they can go roughly twice as long between water changes if they use any method that prevents the high buildup of CYA.  Just note that chlorine does slowly break down CYA and in a hot spa it seems to be at around 5 ppm CYA per month so using Dichlor for a day or two per month makes sense to maintain the CYA level.  As for initial CYA, I suggest using Dichlor initially only because it's very easy to do and dissolves quickly, but one can certainly add pure CYA to the water if they want to -- it just takes longer to dissolve (add it in a small bag or sock in the skimmer equivalent to prevent it settling on a spa surface).

As for starting FC level just before a soak, most people don't want to smell much chlorine or chloramines during their soak so that's why I recommend targeting around 1-2 ppm FC, but you can certainly go higher to ensure you don't run out of chlorine during the soak.  I just figure that the monochloramine will continue to disinfect albeit more slowly and that bacteria don't reproduce very much (nor form significant biofilms)  in the time of a soak and the blast of chlorine right after the soak kills off anything.  However, it is true that if you are concerned with person-to-person transmission of disease during a soak then an FC that is maintained throughout the soak would be technically safer.  So for commercial/public spas that's essential.

[Vinny]

I may have led you to believe that I add dichlor before I soak, I use it after I soak. I use the "Vermonter" method of sanitizing which is to soak in little to no chlorine.

The water out of my tap is low PH, TA and calcium so I need to increase everything in order to balance my water. I stopped worrying about calcium as part of the equation since my spa is close to 100% plastic and when I add baking soda it also affects my PH but just in my tub. So I don't use borax unless my pH is low and I run out of baking soda and the affects of using borax is temporary as it does nothing to the TA.

What I said in the above paragraph is true only for my tub, my pool uses both borax and baking soda.

I don't even think of lithium because of the price. What I remember about the Vermonter method was he experimented with his tub as he was (is) a microbiologist and even after 3 months of using dichlor his tub was bacterially safe. He did also use ozone (I don't) but other than that I'm basically copying what he did. I also think he didn't use non chlorine shock to shock the tub but used dichlor as well.

I guess it makes sense that if you use straight chlorine that is is stronger then it would be if you used one with stabilizer. I was under the impression that you needed to worry about it being too strong at higher levels with no CYA not at the 3 PPM or less levels.

I don't have the data you do but I do see on the forums how people are misled on what they are supposed to do. Luckily there are sites like this.

[chem geek]

3 ppm FC with no CYA has 8 times as much active chlorine as 3 ppm FC with 40 ppm CYA and that's at 104ºF when this difference is smaller compared to cooler temps.

[Vinny]

Thanks for the info!