2.2% bleach (sodium hypochlorite)

[snaxmuppet]

I have recently switched from using dichlor in my tub to bleach. I have tried to get some 5% bleach here in the UK but because of the lock down it isn't widely available. However, I can get some 2.2% bleach. It is thin bleach with no other additives (no perfume, no sufactants). Apart from having to add just over twice the amount to get the same FC level is there any other reasons why I shouldn't use this 2.2% thin bleach?

[dlleno]

should be just fine -- just make sure you start with dichlor first, to achieve approximately 30ppm CYA before switching to bleach

[snaxmuppet]

Thanks... I used dichlor for nearly a week so there should be enough CYA.  

It does seem to push up the pH much more than dichlor. I am now having to add the occasional scoop of pH down to keep it within range. Is this normal when using bleach?

[RDspaguy]

Yes. Liquid chlorine has a high ph, dichlor is neutral, tablets are low. Aeration (air mixing with water, such as jet air controls) raises ph. Mps (non-chlorine shock) raises ph. 

[snaxmuppet]

Thanks for that explanation... so, just to be clear then, it is normal then to need to add pH reducer (sodium bisulphate) to keep the pH down and within range when using liquid chlorine? 

[dlleno]

Without steeling RDs thunder i can say that when the "switch to bleach" method was gaining traction and spa store heads were exploding, one of the early criticisms was upward pH drift.   Then came the research into using borates as a pH  buffer to help, and many have dialed that in pretty well.  Im doing the same as you snaxmuppet....i just use a little more bisulfste .  Watch your TA ... let it drop naturally with use of bisulfate but if it gets too low (below 50) you risk a precipitous pH drop through the floor. 

Youre still using dichlor at first right?  Its not good to use straight bleach without 30ppm CYA present....

[RDspaguy]

No thunder to steal, my friend. I am no chemical expert and bow to your wisdom in these matters. Just giving the best info that I have.

And as far as "heads exploding", one of my earliest jobs in this biz I worked with a guy who swore by bleach. In my 25 years, I have been taught many methods by many people from employers to chemical manufacturers to health departments and finally the Certified Pool Operator program. My conclusion is that there are many ways to maintain your water, but they all have the same goal. It seems to me to be a matter of choice. Most spa stores that I have worked for or dealt with use a computerized test method provided by their chemical supplier which crunches the numbers and spits out a paper with instructions. They do not care about chemical sales, those are provided as a convenience to keep customers, and generate a very small percentage of profits compared to the overhead they require. Their money comes from spa sales and service. How much does a car dealer make from oil sales?

I ran a successful business for 15 years doing only repairs. I did not sell a thing, had no storefront, and only cared about your chemicals if they were destroying your equipment. Which they do on a regular basis. To me, high ph=scale=burned-out heaters, busted jets, clogged filters, and failed circulation pumps. Low ph=shorted heaters, leaking pumps, melted gaskets and pillows, and deteriorated filters. As a result, I like anything that doesn't require daily ph adjustment, because people do not stay on top of it. Maybe you have to drain more often, or spend a bit more. But what it saves you in repair costs is worth it. And, believe it or not, I do not want to see my customers any more than absolutely necessary, nor they me. I am far too expensive!

[snaxmuppet]

Thanks so much for your help and also for your background... it is always interesting to see where people are coming from so that we can put your comments and offers for help in context.

I will look into borates. It does mention borates in my spa's start up instructions but it says it is optional so I haven't looked into it properly yet... perhaps now is a good time for me to do just that

Yes, I used the spa for about a week using dichlor to make sure there was some CYA in the mix before switching to liquid chlorine.

Using the bisulphate is lowing the TA slightly each time as you expected. I shall keep a good eye on that for sure. I test at least daily and when I use the spa I test after to gauge how much chlorine to add to add so TA is being regularly checked.

Once again... thank you for all your help/comments. It is a little scary when first switching to liquid chlorine but the benefits seem well worth the effort from what I can tell. I'll keep plugging away and learning  

[dlleno]

I usually measure out the amount of dichlor that will produce 30 ish ppm in my spa.  Set that aside.   When it is used up i switch to bleach. 

An amusing post script to this is that i cant find bleach today because of the horders so i am using dichlor agsin. However im also using Hot Tub Serum which  contains a mild bacteriacide that is immune to the CYA problem.  Six months and my water is as clear as first fill and my sanitizer decay rate is crazy good

[snaxmuppet]

That is a great idea... how do I know precisely how much CYA is in any measure of dichlor?

I am looking at Hot Tub Serum... just about to read your blog on it

The reason I am using 2.2% bleach instead of 5%, which is normally easy to get here in the UK, is because of the horders and also many retailers of are closed right now. I am sure they will open up once the lock down is lifted so I'll then switch to using 5%.

Thanks for your help with this