Why So Much Bleach?

[propofolboy]

Ok so I have got my tub up and running as per Nitro's directions.

pH 7.7 TA 100 CH 150 Borates 40 Stabilizer 30-40 ppm

I have used Dichlor for about a week and now am using bleach.

I use Purex from Canadian Tire. It is 12.5% apparently of sodium hypochlorite.

I used the pool calculator and it says to use 2 oz to get FC to 3 and 4 oz to get FC to 6, and 8 oz to get FC to 12 (shock).

I put in 4 oz (1/2 cup) and measured my FC about 15 minutes later, and it was only 3!

I did the same the next day. I tried 8 oz (full cup) and it went to 6.

I have a really light bather load, and although I haven't measured CC, I don't think that it would be high.

Does this seem like a lot bleach??

Mike

[Nitro]

That does seem like a lot. Assuming a 350 Gallon tub size, 4 oz should give you ~12 ppm FC. Remember to change the % bleach to 12.5%. How old is that bleach?

I don't know your tub history. Is this fresh water?

[propofolboy]

It was a new fill about 8 days ago.

I don't know how old the bleach is. I bought it just a couple days ago from the store, but who knows how long it was sitting in the store or whatever. That was my thought too.

4 oz of this 12.5% will barely budge my FC level. It's kind of wierd.

My tub is 1450 litres and was brand new.

The dichlor would raise FC pretty easily however (just a couple teaspoons).

[lmartine]

Exactly what is the name of the Purex product? The only thing I can easily find in the frozen north is chlorox at 6%.

Based on the MSDS, I could not find any Purex bleach product with with sodium hypochlorite. Is it called something else on the MSDS?

[chem geek]

I couldn't find the one in Canada, but the MSDS for Purex in Australia is here showing 12.5% Sodium Hypochlorite.

The chart at the bottom of this link shows how even well-made chlorinating liquid will degrade quickly at higher temperatures and higher concentrations. Half of the strength will be lost for 12.5% at 90F in about 70 days. Of course, I don't expect it to be that warm in Canada right now!

You can do a double dilution with a bucket test to see the chlorine strength. If you mix one ounce of chlorinating liquid in one gallon of water (assuming there is no chlorine already in it -- you can test that separately if so) and then take one ounce of that mixture and add it to another gallon of water, then measure the chlorine level and multiply by 1.6 to get the effective "Trade %" of chlorine. If you do this test and end up with 7.8 ppm FC, then that's 12.5%. If you end up with 3.8 ppm FC, then that's 6%.

Richard

[Nitro]

Even if the Purex degraded to 6%, 4 oz would still raise it up near 6 ppm. According to Mike's tests, this stuff would be around 3%.

[LauraG]

Ok so I have got my tub up and running as per Nitro's directions.

pH 7.7 TA 100 CH 150 Borates 40 Stabilizer 30-40 ppm

I have used Dichlor for about a week and now am using bleach.

I use Purex from Canadian Tire. It is 12.5% apparently of sodium hypochlorite.

I used the pool calculator and it says to use 2 oz to get FC to 3 and 4 oz to get FC to 6, and 8 oz to get FC to 12 (shock).

I put in 4 oz (1/2 cup) and measured my FC about 15 minutes later, and it was only 3!

I did the same the next day. I tried 8 oz (full cup) and it went to 6.

I have a really light bather load, and although I haven't measured CC, I don't think that it would be high.

Does this seem like a lot bleach??

Mike

I am using Purox from Canadian Tire. It is 10.8% sodium hypochlorite and the available chlorine content is 10.3%.

[propofolboy]

Yes that is what I'm using.. Purox, not Purex, and your right 10.3%.

Anyway, I still think I got an old bottle.

It doesn't even have a chlorine smell to it..

Does yours?

[Nitro]

Yes that is what I'm using.. Purox, not Purex, and your right 10.3%.

Anyway, I still think I got an old bottle.

It doesn't even have a chlorine smell to it..

Does yours?

I'd say that bleach is old and lost some of it's effectiveness. Luckly bleach is cheap, and you just need to add more. Just go by your FC level and not the actual amount you add. Keep testing FC after you add it, so you know you're adding enough. Careful when you get a new jug, because it should be stronger.

[LauraG]

Yes that is what I'm using.. Purox, not Purex, and your right 10.3%.

Anyway, I still think I got an old bottle.

It doesn't even have a chlorine smell to it..

Does yours?

I'd say that bleach is old and lost some of it's effectiveness. Luckly bleach is cheap, and you just need to add more. Just go by your FC level and not the actual amount you add. Keep testing FC after you add it, so you know you're adding enough. Careful when you get a new jug, because it should be stronger.

Mine doesn't really have much of a bleach smell. I have to use more than I once thought though. We have high bather loads, so on those days, I am putting in about 6 oz. then sometimes, during the soak I add another 4 or 5 oz. (depending how many people and how long) then again after the soak I add another 6 or 8 oz. Now, most days, I just add 6 oz. It is perfect. My water has been fantastic. Nitro and chem geek have done so much to help me.

Could you find the 20 Mule Team Borax that they suggested? I haven't found any, so I am using Omni Presence Plus for my borates.

I just got another 4 bottles of Purox from Canadian Tire.

[chem geek]

So the Canadian Tire Purox is shown here, but they don't actually list its strength. You are reading it from the bottle and all I can figure is that for whatever reason in some cases it's not as strong as it's supposed to be. Testing the strength with dilution using distilled or filtered water would tell you. Having it register less than expected in a spa could mean its weak, but could also mean that the spa has something in it that is consuming chlorine relatively quickly.

[propofolboy]

Ya I found the 20 Mule Borax at walmart.

I'm starting to think Clorox might be better than the canadian tire stuff though.. I think purox is not much more concentrated, and more expensive (4.99 versus like 2.50).

Mike

[LauraG]

Ya I found the 20 Mule Borax at walmart.

I'm starting to think Clorox might be better than the canadian tire stuff though.. I think purox is not much more concentrated, and more expensive (4.99 versus like 2.50).

Mike

Thanks Mike, I will check Walmart again...

What kind of Clorox are you going to get? I have found that the Purox is working quite well, but, if clorox will do the same for half the price.... why not?

[chem geek]

Thanks Mike, I will check Walmart again...

What kind of Clorox are you going to get? I have found that the Purox is working quite well, but, if clorox will do the same for half the price.... why not?

Laura,

It really comes down to whether or not Purox is more concentrated than bleach. If it is, then it might be economical, but if it's about the same strength as bleach, then bleach is less expensive. If you go with bleach, make sure it is unscented and not a "special" type such as one that says it's for "outdoor" use. Basically, Clorox Regular that says "6% Sodium Hypochlorite...5.7% Available Chlorine" is the best. If you get an off-brand bleach, it may need to be Ultra to be at full strength -- in Canada maybe even the Clorox needs to be Ultra (the Regular is OK, but if both Clorox Regular and Ultra are available, then the Regular is probably 5.25% while the Ultra is unlabeld in strength and probably 6-7%).

Richard

[LauraG]

Thanks Mike, I will check Walmart again...

What kind of Clorox are you going to get? I have found that the Purox is working quite well, but, if clorox will do the same for half the price.... why not?

Laura,

It really comes down to whether or not Purox is more concentrated than bleach. If it is, then it might be economical, but if it's about the same strength as bleach, then bleach is less expensive. If you go with bleach, make sure it is unscented and not a "special" type such as one that says it's for "outdoor" use. Basically, Clorox Regular that says "6% Sodium Hypochlorite...5.7% Available Chlorine" is the best. If you get an off-brand bleach, it may need to be Ultra to be at full strength -- in Canada maybe even the Clorox needs to be Ultra (the Regular is OK, but if both Clorox Regular and Ultra are available, then the Regular is probably 5.25% while the Ultra is unlabeld in strength and probably 6-7%).

Richard

thanks Richard, I have taken down the information. I have 4 bottles of Purox, and things are going well, so I am not too inclined to change , but it is nice to be informed!!!

[Accent]

I'm not a chemist, but I have personally found that 1 week of use doesn't build up enough CYA to switch to bleach, and maybe that's why you're having to use more bleach for the FC to stay up. Without CYA, the chlorine will dissipate more quickly. MPS and an ozonator may keep CYA from building up quickly, and with them, I start switching gradually to bleach after about 4 weeks. That's my experience, anyway. Hope it helps.

[chem geek]

An ozonator will break down chlorine so with more CYA in the water such breakdown will occur more slowly so in your situation that makes sense. However, if that were the case, then you should find that you need to add more chlorine during the 1st week, less then 2nd week, and even less after the 4th week. The biggest drop would occur over the first few days as you are first building up some CYA.

MPS and an ozonator don't prevent CYA buildup, but they do both oxidize organics which would lower chlorine demand were it not for the ozone oxidizing some chlorine itself. It could also be that the ozonator and certainly the MPS lets you use less chlorine so the buildup of CYA is slower. I you're only adding chlorine at a rate of 1-2 ppm FC per day, then it will take more weeks to build up the CYA.