Lithium Chloride Vs Homebrand Bleach

[mgrobins]

Hi, I live in Australia and have been in and out of these forums for some time. Have some questions ref sanitiser...

Homebrand Bleach is one I found to be free of a surfactant and is listed at 4.2% strength. It also lists Sodium Hydroxide as an active ingredient (9g/L). Is this additional chemical a problem?

I found that since using bleach I have experienced more rapid deterioration of my foam head-rests and spa cover. I havd no CYA for a while and thought this was the cause but I would like to confirm the bleach I am using is OK.

For general info I did a calculation on cost.

Bleach runs at 5.6 cents per application and the Lithium at 39 cents (purchasing 1kg of lithium). I think I can halve that by purchasing a 'bulk' container (a "giant" 2kg haha) but it still works out far superior to use bleach.

I just want to know what I'm using is ok and prevent excessive deterioration....

On the topic of foam headrests... any suggestions for a way to preserve them better? Jacuzzi ones are not the high standard I would have liked to see from them... (I have made moulds at work and am in the process of fabricating my own from silicone).

Cheers,

[waterbear]

Hi, I live in Australia and have been in and out of these forums for some time. Have some questions ref sanitiser...

Homebrand Bleach is one I found to be free of a surfactant and is listed at 4.2% strength. It also lists Sodium Hydroxide as an active ingredient (9g/L). Is this additional chemical a problem?

I found that since using bleach I have experienced more rapid deterioration of my foam head-rests and spa cover. I havd no CYA for a while and thought this was the cause but I would like to confirm the bleach I am using is OK.

For general info I did a calculation on cost.

Bleach runs at 5.6 cents per application and the Lithium at 39 cents (purchasing 1kg of lithium). I think I can halve that by purchasing a 'bulk' container (a "giant" 2kg haha) but it still works out far superior to use bleach.

I just want to know what I'm using is ok and prevent excessive deterioration....

On the topic of foam headrests... any suggestions for a way to preserve them better? Jacuzzi ones are not the high standard I would have liked to see from them... (I have made moulds at work and am in the process of fabricating my own from silicone).

Cheers,

All sodium hypochorite does contain some excess sodium hydroxide. If the pH was not kept high the chlorine would gas out very quickly and it would lose strength. Once it is in the water you will have hypochourous acid, hypochlorite ions, and sodium ions. They excess hydroxide ions will be taken care of by your buffer system (bicarbonates and possibly borates if you have added them). Lithium hypochlorite will do exactly the same with the exception of of forming lithium ions instead of sodium ions when dissolved. Lithium and Sodium are both metals in the same chemical family with very similar properties. Lithium hypochlorite is also alkaline (an excess of hydroxide ions when dissolved) as is calcium hypoclorite so the pH effect is pretty much the same as sodium hypochlorite. You could say that in solution it forms lithium hydroxide (because of the ionic species that would be present) but since it is sold as a solid this would not be listed on the label since this does not occur until it is in solution. Sodium hypochlorite is sold as a liquid so the sodium hydroxide has to be listed as an ingredient.

Bottom line, the next effect when added to the water is basically the same.

Your foam degredation is most likely from the chlorine and would have happened from any unstabilizied chlorine source (lithium, sodium, or calcium) and is most likely related to not having any CYA in the water and was accelerated by the high temps found in hot tubs and spas. Degredation of bathing suits is also very common under those conditions. Many things do not survive in pools and spas and need to be replaced even with the best care such as skimmer nets, foam floatation devices, piillows, etc.

[simonc]

I can't help you with the chemistry related questions, but I would like to suggest the diclor-then-bleach method if you are not already using it. It's described in Nitro's post here. It will add enough CYA so that the chlorine has less of an effect on your spa pillows and other components.

Just a side note: A have a Jacuzzi spa too. My pillows stayed in good condition for about 2-3 years then they started to deteriorate. They are expensive to replace. I just took them out completely. Yes, it looks a little funny but I enjoy the tub just as much. You can buy aftermarket (not Jacuzzi) pills that hand over the side of the tub. They are relatively inexpensive (about US$20 each) and you can take them out of the tub while you are not using them. This makes them last almost forever.

Good luck,

- Simon

[mgrobins]

Hi,

thanks so much for the responses .

I'm glad I was on the money ref the likely source of deterioration and will continue to use the bleach.

I don't use Dichlor... I calculate the specific amounts I need for the chemicals and add them at startup (my local shop just fills a small container with Cyanuric acid for me). It takes some time to disolve but works well.

My issue with not using CYA arose after I followed the advice of my 'professional' store owner down trhe road. They can stick to pools and I'll stick to my spa I think.... most of the guys there don't even question me anymore because they don't know what the chemicals in the spa products do (eg "silk" which is Boric Acid).

I use the calculator from this page: http://www.thepoolcalculator.com/

I wonder what sort of headrests I could fit to my Jacuzzi... it's a J-385 so the outside is sort of rounded/angular leading to the timber surround. Seems like a good suggestion though . I'll see how my own castings go to (buying the pillow/surround combo is $60 per set and I need 5).

[chem geek]

My issue with not using CYA arose after I followed the advice of my 'professional' store owner down trhe road.

Hardly anyone in the pool and spa industry understands the chlorine/CYA relationship even though it has been known since at least 1974 as described in this paper. The prevailing (inaccurate) "wisdom" is that Cyanuric Acid (CYA) is only needed for outdoor pools (or outdoor uncovered spas) that are exposed to sunlight because the UV in sunlight breaks down chlorine. This ignores the fact that CYA doesn't just protect chlorine from breakdown from sunlight, but combines with chlorine to make the resulting active chlorine (hypochlorous acid) level much, much lower by orders of magnitude. Fortunately, it takes very low active chlorine levels to kill most pathogens, but not having CYA means that the higher active chlorine level is that much more reactive to swimsuits, skin, hair, spa covers and pillows, pool equipment, etc.

The 4 ppm FC with 30 ppm CYA that is recommended in the Dichlor-then-bleach method is roughly equivalent to 0.6 ppm FC with no CYA at hot 104ºF spa temperatures (at lower temps such as 90ºF it's around 0.3 ppm FC with no CYA and at 80ºF it's around 0.15 ppm FC with no CYA).

One more point. Any concentrated chemical should be added slowly with the circulation pump (and maybe the jets, unless they splash) running to ensure thorough mixing.

[mgrobins]

Once CYA is added I assume the drop kit I am using is testing the FC level and not TC?

I add enough bleach to keep it at 1-2ppm.

[chem geek]

All chlorine test kits will measure the same thing before or after CYA is added. The reason is that chlorine is released from CYA quickly (usually in a second or two) in the time of the test. The CYA acts as an active chlorine (hypochlorous acid) buffer holding it in reserve. So it significantly lowers chlorine effects, but replenishes any used up chlorine so that you do not run out. The chlorine tests measure this entire amount and all of the chlorine attached to CYA ends up getting measured as Free Chlorine (FC) and not as Combined Chlorine (CC). This is why it is so critically important to measure the CYA level in addition to the FC level. FC alone doesn't tell you anything about the level of sanitation/disinfection/oxidation in your pool or spa.

[mgrobins]

ok.

CYA was measured at 29ppm. So going on your suggestion I should apply chlorine to be measured at approx 4ppm which will mean an available chlorine level of about 1ppm with the remained bound by CYA and in an equilibrium state? I have my spa temp at 37C (99f).

I guess my goal is consistant sanitation without a chlorine smell or the harsh feeling some public pools give. Bather load is low (myself once per day at most) and I alsways shower prior to time in the spa....

Thanks for the useful advice and explanations too...

[chem geek]

At 99ºF, 4 ppm FC with 29 ppm CYA at a pH of 7.5 will have 0.21 ppm as active chlorine (hypochlorous acid), 0.29 ppm as hypochlorite ion, and 3.5 ppm as chlorine bound to CYA (in several compounds called chlorinated isocyanurates). Don't worry about this allocation. Just make sure you've got 1-2 ppm FC by the start of your next soak. That will minimize the amount of chlorine during your soak and then after your soak add about 5 fluid ounces of 6% bleach for every person-hour of soaking, though you can adjust this so that you still have a reasonable residual before your next soak. On average, you'll probably have roughly 3-4 ppm FC which will be fine for disinfection at that CYA level while during your soak the chlorine will be lower and not be offensive. If you have a hot tub party, then you could have more chlorine during the soak if you want to prevent person-to-person transmission. Since CYA is usually not used in commercial/public spas, you shouldn't be anywhere near that kind of experience in smell, feel, or disinfection by-product production.

[Hillbilly Hot Tub]

FYI, if the tub has an ozone, that will chew up pillows and covers fast also. We suggest removing the pillows after spa use if you want them to last longer. its a pain, but a choice you can make.