Oxidizers - Do They Work ?

[OttawaGreg]

I'm trying to stretch my water another month before dumping and refilling. I've had it only 3 months but we use the tub allot. The water is balanced but I'm getting the foaming, which I believe is the sign that TDS is high. I really should bring a sample in and get it checked. My test strips don't measure TDS of course...

Anyhow, I'm looking at these oxidizer products and their descriptions and wondering if they could help. Do they really do what they claim or just mask the problem and all the while add to my TDS?

Anybody with experience?

Here is a link to the Spaguard products that I use and their Oxidizer selection.

http://www.biolabinternational.com/bioguar...rd/oxidizer.htm

thanks,

Greg

[chem geek]

Test strips cannot measure Calcium Hardness (CH) and only measure Total Hardness and they are not as accurate as drop-based test kits. Please do yourself a favor and get yourself a good test kit with a FAS-DPD chlorine test (assuming you are using chlorine), either the Taylor K-2006 you can get at a good online price here or the TF100 test kit from tftestkits.net here with the latter kit having 36% more volume of reagents so is less expensive per test.

What have you been using as your source of chlorine (you linked to products but didn't indicate which sanitizer)? If you have been using only Dichlor, such as SpaGuard Chlorinating Concentrate, then with heavy use you have probably built up the Cyanuric Acid (CYA) level in the tub very high and that makes the chlorine much less effective to the point where it will no longer oxidize bather waste quickly enough. That will make the water dull and could contribute to the foaming as well. For every 10 ppm Free Chlorine (FC) added by Dichlor, it also increases Cyanuric Acid (CYA) by 9 ppm. Whereas the chlorine gets used up and converted to chloride (salt), the CYA doesn't go away.

For example, if you use the tub with one bather-hour every day (i.e. two bathers for 30 minutes or three for 20 minutes), then this requires around 7 ppm FC in 350 gallons so that would build up CYA at a rate of around 190 ppm per month which is very high.

It is possible that the active chlorine level is so low due to the high CYA that bacteria are able to grow (including biofilms) as another poster says this can cause foaming which is what you are seeing. The high CYA would also slow down chlorine's oxidation rate getting rid of bather waste. Regardless of the exact cause, high CYA levels make chlorine less effective (lower its effective concentration, though that does not show up in tests since test measure chlorine reserve not active chlorine levels). The problem is not high TDS per se, but specifically the high CYA level.

See Nitro's links here on the Dichlor-then-bleach method. Note that you will likely need to lower your TA if you switch to that method, but the water will likely last almost twice as long before needing a water change.

Richard

[OttawaGreg]

Richard,

I've been thinking about moving to Dichlor then Bleach but have no idea how much Bleach liquid to add. Are we talking about 30->60 ML for an average dose and 300 ML for a shock? Or are the quantities larger? My tub is 280 gallons - 1050 litres.

The other thing with the Dichlor/Bleach method is I use a floater with tabs, does that go away and I need to do daily (or more regular) doses of Bleach? When I leave for a long weekend I just top up the tabs and go, what do I do then with Bleach?

To answer your question, yes, just Spaguard so Dichlor as my sole sanitizer.

I will be getting a water sample tested by the pro's tonight and report back the numbers here for record. I am sure I know what they will say, dump and re-fill, but I am curious where I am at. Also about the CYA number as you mention.

Greg

[Nitro]

The other thing with the Dichlor/Bleach method is I use a floater with tabs, does that go away and I need to do daily (or more regular) doses of Bleach? When I leave for a long weekend I just top up the tabs and go, what do I do then with Bleach?

Greg, what floater with tabs are you using??? Dichlor doesn't come in Tabs. Are you sure you're not using Trichlor??? If so, that would explain why your pH is consistantly low. It's very acidic.

[chem geek]

(deleted duplicate post)

[chem geek]

I'll bet he is using SpaGuard Brominating Tablets so this is a bromine spa, not a chlorine one. The link he gave has a floating feeder that uses brominating tablets, not Trichlor. Greg, is that correct?

Bromine tablets have DMH and that might build up similar to the way that CYA builds up. It doesn't bind to chlorine the same way that CYA does, but I don't know the side effects if a lot of DMH were to build up in the spa. It's possible that this leads to the sort of problem that Greg is seeing. If one wants to use bromine tablets, but reduce the buildup of DMH, then one can lower the output setting on the feeder and supplement with shocking/reactivating the bromide to bromine by adding either chlorine or non-chlorine shock on a regular basis. Of course, this starts to get closer to the daily maintenance of the Dichlor-then-bleach method so one could just switch to that method instead (after a water change since you can't convert a bromine spa into a chlorine one without changing the water).

[OttawaGreg]

All,

The SpaGuard Chlorinated Concentrate is Lithium Hypochlorite 29%

The SpaGuard Smart Tabs are Trichloro-S-Triazinetrione 97%

Are either of these Dichlor?

I got a sample tested tonight and here are my readings;

TDS - 1700

Tot San. - 2

Free San. - 2

pH 7.0

T.A. - 90

C.H - 140

So the T.D.S is high but I've seen it at worse. I just used it tonight and found very little to no odor. There is a bit of foaming but that appears to lessen the closer I get my pH to ideal.

The SPA specialist who tested my water said 3 months is the usual max and I need to drain it. So, Should I dump the tabs & concentrate and go with bleach? Will this stretch my refills by adding less to the TDS?

If so what kind of guide is there for the quantity of bleach to add?

thanks,

Greg

[chem geek]

Greg,

Well that explains a lot. The chlorinated concentrate is lithium hypochlorite and is very similar to using bleach (which is sodium hypochlorite) except that it is a LOT more expensive. The Smart Tabs are Trichlor. For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm. Trichlor is also VERY acidic, which explains your low pH in spite of high CYA.

As for using the Dichlor then bleach method, see Nitro's Approach to Water Maintenance. See the other links in Nitro's profile to learn more about chlorine demand and other items.

Yes, dump your water, refill, and follow Nitro's instructions, including the use of Borates.

As for how much chlorine you will need, it depends on your tub usage and you can read Nitro's chlorine demand link for more info. Roughly speaking, every person-hour of soaking (2 people for 30 minutes, 3 people for 20 minutes) at 100-104F requires 3.5 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (MPS). You would start out using Dichlor for the first days or week (depending on usage) until you've cumulatively added 12 teaspoons of Dichlor to your 280 gallon tub and thereafter use bleach until your next refill.

Richard

[OttawaGreg]

Here is my plan for November, once I dump the current water and refill. Thanks for all your help and suggestions. I still have a few questions though.

I just bought a Nature2 Spa Clarifier from Zodiac. The SPA pro convinced me to give it a try. It lasts 4 months and is supposed to reduce your consumptions of oxidizer & sanitizer dramatically. www.zpc.ca. This will change slightly my method going forward. You place it inside your filter, I am thinking it acts like a Brita filter of sorts. It has these requirements:

1. Initial super-oxidation with sodium dichlor is required to burn off contaminants and activate Nature2 Spa. (this is in-line with Nitro's Dichlor then bleach method).

2. After each tub use add MPS as needed. (OK, just what is MPS? I mean, as in what product is this?)

3. As needed, shock with 1.5 tablespoons of sodium dichlor p/1000 litres.

As an alternative to MPS, sodium dichlor can be used.

I do not have dichlor. I have Trichloro & Lithium-Hypo. I looked at the SpaGuard product line and they have a "Stabilized Chlorinates Granules" product with near neutral pH. I am guessing then this is dichlor and will get this.

1. Dump tub - refill - superoxidate (chlorinate) with dichlor.

2. Balance water

3. Install Nature2 Spa Clarifier

4. ? Question Time ? - which sanitizer / oxidizer do I use for daily maintenance?

a) If I go with Clorox bleach then my pH will drift up as it's pH=13. I can then use Muriac Acid to lower pH or pH-down or even Lo-N-Slow. Whichever has the least effect on T.D.S. I could even switch back and forth (sanitizer) with Trichloro as it will lower the pH as it's pH=3. I mean put the floater back in the tub with tabs for a few days to sanitize and lower pH instead of Clorox.

If the Nature2 does it's job as advertised I just use very small amounts of Lithium or dichlor every few days.

c) If my pH (for some reason) is very low I use Borax to raise it with little effect on TA.

I should probably email the Zodiaz (Nature2) folks and ask them if their product will work with Clorox bleach as the sanitizer.

Any thought on this plan? (before I actually try it :-)

Greg

[chem geek]

Nature2 will NOT change the amount of sanitizer or oxidizer that you will need. That's just complete and totally inaccurate information from the "SPA pro". Nature2 is a mineral cartridge so the copper/silver ions slowly kill pathogens even when there is no other sanitizer present so it should be seen as an insurance policy if you let your sanitizer level get too low. The silver ions can also be used in conjunction with non-chlorine shock (MPS) and this combination is an effective sanitizer at high spa temperatures (100-104F) and is the basis of the "low chlorine" approach in Nature2. If you read the Nature2 owner's manual, you will find that the "low chlorine recipe" says to use 1 tablespoon of MPS per 250 gallons (though it says to add more if the MPS test strip reading is still low) before each soak (around 3 ppm FC) and to add 1 tablespoon of MPS per 250 gallons after each soak. As needed, it says to shock treat with 1.5 tablespoons of Dichlor. It also says you can use Dichlor instead of MPS where they say that 1 tablespoon of Dichlor equals 3 tablespoons of MPS (it's actually 2 tablespoons of MPS if it's 43% MPS). These are not significantly lower sanitizer quantities since 1 tablespoon before and 1 tablespoon after each soak in 250 gallons (so scaling up for 350 gallons) would be enough for 1.2 person-hours of soaking in a 350 gallon spa. They also didn't scale this for bather load -- if you have more people soaking longer, then more is needed and they account for that by saying to measure sanitizer (MPS) levels and add more if needed. Also, note that MPS is expensive and Dichlor is also more expensive than bleach.

Yes, the SpaGuard Stabilized Chlorinating Granules that are pH neutral (upon addition; after consumption they are net acidic) are Dichlor.

When you use bleach, your pH will NOT drift up towards a pH of 13. This is also misinformation from your "SPA pro" who doesn't know what he is talking about. Yes, the pH of bleach is high (Clorox Regular is around a pH of 11.7), but that is only upon addition of the bleach to the water. When the chlorine gets used up oxidizing ammonia and urea and other organics in the spa, the pH drops since the consumption of chlorine (which turns it into chloride, that is, salt) is an acidic process. The net result is nearly pH neutral. There is a small amount of "excess lye" in bleach, but if you use Clorox Regular 6% bleach then this amount is minimal. The main source of pH rise will be from carbon dioxide outgassing and chlorine outgassing. You can minimize the former by having a low Total Alkalinity (TA) down to 50 ppm if necessary. The use of 50 ppm Borates also helps reduce the pH swings when adding bleach.

The TDS is irrelevant since it is mostly just plain sodium chloride salt. Forget TDS -- another thing your "SPA pro" has got dead wrong. The reason for the problems in your spa was probably due to the continued use of stabilized chlorine, in particular Trichlor, that increased the Cyanuric Acid (CYA) level to the point of making the chlorine ineffective so it would no longer oxidize bather waste quickly enough and the water would turn bad. People who don't know any better just say it's TDS because TDS does increase over time along with the CYA when using stabilized chlorine so they blame TDS instead of properly blaming the CYA specifically. The Trichlor was also why your pH was consistently too low. Consider salt pools with saltwater chlorine generators (SWG) that have 3000 ppm salt and around 3200 ppm TDS. Gosh, those pools must be just awful, right? WRONG. TDS is not relevant unless it gets very, very high in which case then the higher conductivity makes corrosion more likely -- you aren't going to get that high before you next change your spa water.

Again, please read Nitro's guide and follow those instructions. Do not try and mix things up using Trichlor tabs. Yes, the acidity on occasion could be used in place of Muriatic Acid or dry acid, but it will increase CYA so you would not want to overdo it so I wouldn't use it at all. Just try the Dichlor-then-bleach method as is. Bleach works perfectly well with N2 since Dichlor and bleach produce IDENTICAL chlorine in the water. The only difference is that Dichlor also adds Cyanuric Acid (CYA). You want some initially, but want to stop when it gets to 30 ppm.

If you follow the Nature2 instructions and superoxidize the water with Dichlor at the rate they suggest of 1.5 tablespoons (4.5 teaspoons) per 250 gallons, this is approximately 12 ppm Free Chlorine (FC) and would add around 11 ppm Cyanuric Acid (CYA) so you would continue to use Dichlor for a few days or so (depending on your rate of usage) and would then switch to using bleach after that.

By the way, the guidelines I gave you on person-hour oxidizer amounts are a rough guide. As Nitro notes in his procedure, you adjust the amount of sanitizer/oxidizer you use in order to get a measurable residual by the next time you soak (usually the next day).

Richard

[OttawaGreg]

Richard,

Thanks for the terrific and very explanatory reply. I will start to put "quotes" when I refer to the "Spa Pro" from now on

My current problem is that my addition of Borax (which is borates right?) is raising the pH but my continued use of the Trichlor Tabs is beating it down. I will be changing my water in a months time so I think I will pull the floater now and try some Clorox 6% bleach to see how that reacts. Can't hurt and will likely start to stabilize my pH drift.

In November once I've dumped the water I will follow Nitro's method, with the addition of the Nature2.

Greg

[limulus]

Greg,

I don't come on here much these days, but I used the tub last night and thought I would pop onto the forum for a quick look. I can vouch for N2 if you follow the directions. I am in my second season of using Nature 2. You still have to use dichlor...just at a lower concentration. If you follow the manual and balance your water first, then shock with diclhor, not trichlor, then add the N2 cart, you'll have pretty good results. You will also have to add MPS as Richard said. The MPS basically frees up the chorine so it can work again. You should probably read up on free chlorine vs combined chlorine. Last season, I started out using the dichlor-only method that Richard mentioned instead of MPS. It worked, but my CYA went up too quickly and I had issues with pH. Now, I add 3tbs dichlor about every 14-20 days (our tub is 500gal). One more thing in regard to N2 cartridges: they are expensive, but if you look on certain auction type sites, you can find them in multi packs for a lot less per unit. I also change mine every three months, not four.

I have test strips a Taylor chemical kit a pH meter and even a TDS meter. You should definitely get a good kit like the Taylor. For daily use, I use the strips and the pH meter. For weekly testing, I use the Taylor kit. If the tub has been used a lot, I'll use the Taylor kit especially for pH. If you decide not to use the N2 carts, just do what chem geek and Nitro have written. I've only been here a year, but I read a lot of posts and those guys have educated a lot of people.

[chem geek]

Greg,

While you are still using Trichlor, if your TA is getting low you can use pH Up (Spa Up) to raise the pH and TA at the same time. With a higher TA level, the aeration of the jets will help keep the pH from dropping as quickly. The addition of Borates does raise pH, but it only raises TA half as much so your TA will drop over time if you just use Borates for pH control. The use of bleach would help you out IF you used that instead of the Trichlor (or turned down the automatic feeder on the Trichlor floater).

As for what to do with N2 after the next refill, you have two choices. You can follow the N2 low-chlorine recipe which is mostly using MPS regularly and occasionally Dichlor (plus using Dichlor initially on startup) OR you can use the Dichlor-then-bleach method described in Nitro's link. Either method will work fine with N2. The former is more expensive due to the MPS and it completely avoids chlorine during soaking while the latter is less expensive and has a small amount of chlorine during the soak (the way most people do it which is to add the bulk of the bleach after a soak).

Some people find MPS irritating so if that happens to you then you can try Dichlor-then-bleach. Which method to use is up to you -- most people are pretty happy with either method, though as limulus noted the low-chlorine recipe does still require occasional Dichlor to keep the water clean and clear.

Richard

[OttawaGreg]

Greg,

While you are still using Trichlor, if your TA is getting low you can use pH Up (Spa Up) to raise the pH and TA at the same time. With a higher TA level, the aeration of the jets will help keep the pH from dropping as quickly. The addition of Borates does raise pH, but it only raises TA half as much so your TA will drop over time if you just use Borates for pH control. The use of bleach would help you out IF you used that instead of the Trichlor (or turned down the automatic feeder on the Trichlor floater).

As for what to do with N2 after the next refill, you have two choices. You can follow the N2 low-chlorine recipe which is mostly using MPS regularly and occasionally Dichlor (plus using Dichlor initially on startup) OR you can use the Dichlor-then-bleach method described in Nitro's link. Either method will work fine with N2. The former is more expensive due to the MPS and it completely avoids chlorine during soaking while the latter is less expensive and has a small amount of chlorine during the soak (the way most people do it which is to add the bulk of the bleach after a soak).

Some people find MPS irritating so if that happens to you then you can try Dichlor-then-bleach. Which method to use is up to you -- most people are pretty happy with either method, though as limulus noted the low-chlorine recipe does still require occasional Dichlor to keep the water clean and clear.

Richard

Richard, All,

I went out today and bought Dichlor and MPS. I took out the floater yesterday with the tabs of Trichlor, so my chlorine dropped to zero and I started using bleach. I did two installs of about 2-3 tbsp or 90ml of bleach and each brought the free chlorine up by 1 point. So I should now have 2. I also gave it a nice 100 gram dose of potassium monopersulfite (SpaBoss is their brand) and will be using the tub tonight (soon) to see how it feels. The water is old so its in need of that flush as I am planning in November, but I thought I'd get a trial period going now with this new method to see how things go.

If things go well I will have a bunch of chemicals that will go onto a shelf in the laundry room. I find it funny how all these expensive yet easy to use treatments are actually harder on you, the water, and your pocketbook. If more people tuned into this forum and listened to the educated participants they would be much better off.

Here is a list of what I think will be all I or any spa owner really needs to balance and maintain your water.

Dichlor (the most expensive item but only used at the open of a new fill)

MPS (not to bad as you only will use a small amount)

Borax (cheap, and works well and is stable)

Baking soda (it's in my fridge anyhow)

Muriac acid (not expensive- local hardware store)

Clorox bleach (dirt cheap)

And well my Nature2. This is a trial and I'll have to see how this works. At $40 it lasts 4 months, so that is $10 a month.

I'll report back my progress as I think it could benefit people new to the spa thing. I am the typical newby using all the store bought chemicals now switching over to a more natural method, say chemistry based, with all your great help.

Greg

[chem geek]

Greg,

The only other thing I'll mention is that MPS in the water will measure on the chlorine tests, usually as Combined Chlorine (CC), but at higher concentrations or soon after adding it then it can measure as Free Chlorine (FC). There are kits to remove such interference (the Taylor K-2042, for example) if this becomes important to you. Since either chlorine or MPS in a spa will provide sanitation when using N2 (silver ions), it's probably not a big deal so long as you don't worry about any CC that may be measured. You often measure CC anyway after a soak as it takes an hour or so for chlorine to oxidize the bather waste.

Richard

[OttawaGreg]

I have been using Clorox 6% bleach now for a few days and find it hard to keep a free chlorine reading. I either go to zero or close to it. I am adding 4 oz or about 120 ml of bleach before or after using the tub and the next day it's close to zero. With a 280 gallon tub on a daily use with two bathers what amount of bleach is normal?

The pH is 7.3 and TA about 140.

I was expecting to be adding around 2 oz of bleach a day but maybe that was unrealistic. Now it looks like 4 tbsp is barely enough. Maybe 6-8 is what I need. Am way off base here or is that the norm?

BTW the water is better now with bleach, that is a given. Feels and smells better and looks great. Less foam and feels right. pH is not bouncing around although TA is high.

thanks,

Greg

[Nitro]

I have been using Clorox 6% bleach now for a few days and find it hard to keep a free chlorine reading. I either go to zero or close to it. I am adding 4 oz or about 120 ml of bleach before or after using the tub and the next day it's close to zero. With a 280 gallon tub on a daily use with two bathers what amount of bleach is normal?

The pH is 7.3 and TA about 140.

I was expecting to be adding around 2 oz of bleach a day but maybe that was unrealistic. Now it looks like 4 tbsp is barely enough. Maybe 6-8 is what I need. Am way off base here or is that the norm?

BTW the water is better now with bleach, that is a given. Feels and smells better and looks great. Less foam and feels right. pH is not bouncing around although TA is high.

thanks,

Greg

Forget the "Normal" amount of Bleach. There is no such thing. The "Normal" amount of bleach is whatever it takes to oxidize all bather waste, and kill off all the pathogens. If you find FC is dropping to zero (or close), use more. It's as simple as that. Read my link below about Chlorine Demand (CD) for more info.

[chem geek]

Nitro is right, of course, you need to add more so you have a residual before the next soak. Roughly speaking, it usually takes 5 fluid ounces of 6% bleach for every person-hour of soaking. 4 fluid ounces might work for 2 people soaking for around 25 minutes, but this is only a rough guide. Once you get behind, it will take more chlorine to catch up so just add more until you start measuring a residual and get a feel for your actual usage. Let us know your actual soak time and usage as I like to compare the guideline against actual real usage.

[OttawaGreg]

OK, it was good to just hear that there is no "normal" amount to add, or no "expect to add x" daily. I just need to up my dose. I have a clear plastic squeeze bottle marked with two oz. ticks and was adding 2 before and 2 after and it was not enough. I'll mark it at 5 oz points and start using that nightly.

We are still in the hot tub honeymoon stage and use it nightly for say 45 minutes or more. Sometimes just myself but usually the two of us. Our two boys get in there once a week as well. I've also been adding potasium monopersulfite to oxizide the waste with good results. Makes the water more fizzy and light.

I keep a log so in a few days I should know what our expected bleach additions should be and will report back. It would be good to be able to give people a rough guideline for the bleach method.

Greg

[chem geek]

Though one person for 45 minutes might need around (45/60)*5 = 3.75 fluid ounces of 6% bleach, two people would need closer to 2*(45/60)*5 = 7-1/2 fluid ounces. So it does appear that you haven't been using enough, but the best way to tell is to simply add enough to measure a residual the next day.

[quantumchromodynamics]

Greg, have you had your cyanuric acid level tested yet? Also, is there some reason that you're reluctant to drain and refill your tub?

[OttawaGreg]

Greg, have you had your cyanuric acid level tested yet? Also, is there some reason that you're reluctant to drain and refill your tub?

I am not sure how to get the "cyanuric acid level" measured. This is not given by the spa testing place here. They did give me my Total Dissolved Solids and it was 1700. I just use simple strips and will invest in a proper kit one day soon. I guess the Taylor (??) kit would be sufficient.

I'm trying to stretch the drain and refill into November as it get's quite cold here and we have long winters. So my hope is to do it in November and last until March when there is a chance of a warmer day for the next change. I'd be nervous trying to drain it and have something freeze in Jan. or Feb. In Ottawa Canada it get's down to -20 -30 Celsius in those months.

Greg

[Nitro]

I am not sure how to get the "cyanuric acid level" measured. This is not given by the spa testing place here. They did give me my Total Dissolved Solids and it was 1700. I just use simple strips and will invest in a proper kit one day soon. I guess the Taylor (??) kit would be sufficient.

TDS means nothing. Salt reads as TDS and is ok to have at much higher levels. CYA is what you need to worry about. I'd get your CYA level checked (better yet, buy a kit and test yourself). My guess is it's high.

I'm trying to stretch the drain and refill into November as it get's quite cold here and we have long winters. So my hope is to do it in November and last until March when there is a chance of a warmer day for the next change. I'd be nervous trying to drain it and have something freeze in Jan. or Feb. In Ottawa Canada it get's down to -20 -30 Celsius in those months.

Using the Dichlor/Bleach method, you can safely go six months between water changes.

[quantumchromodynamics]

Go to a pool store to have your cyanuric acid tested. Ignore them when they tell you that you don't need to worry about cyanuric acid in a hot tub. Or, just tell them that the water is from your pool so you won't have to argue with them.

Also, make a second test sample that is 1/4 hot tub water and 3/4 tap water as a reference in case the level is too high for a normal test to read. The highest that a cyanuric acid test can read is about 100 ppm. Multiply the result by 4 to get the total cyanuric acid level.

You could drain and refill now and also again right before you think it will be your last chance before winter. Draining and refill is not too difficult or time consuming. Also be sure to clean out your filters any time you drain and refill.

[OttawaGreg]

BTW, I did go to the "pool store" and get my water tested the other day and had a chat with the "pro" about using bleach. He didn't say not a good idea at first but then warned me that I could potentially void the warranty on my spa. He mentioned that there are other things in bleach (not specified) that can harm or "pit" the jets and damage the chrome. That bleach is highly corrosive and could damage the metals in the pump etc. He also said there are things added to the chlorine products that help to protect the hot tub parts.

hmmm....

When I look at the bottle of bleach it has the same warning symbols as my chlorine. Don't drink it basically and careful not to splash it in your eyes or on your skin.

I am using the standard 6% bleach. All is says is sodium hypochlorite.

Greg