Switched from Cal Hypo to Bleach

[Jakebear]

Waste and Dave --- and others.

Again, thanks for your help. Here’s where things stand.

There is no gritty feel to the stain, and TA and CH are 80 and 240 respectively, pH is 7.5.

Last week I ordered a Taylor Iron Test Kit (K-1716) and I already had the Taylor Low Range Copper Kit (K-1730). Got it the next day (really fast service from Taylor).

This morning I finally got around to running both tests ---- Iron came up 0 in the pool and 0 in my well water. Copper also tested 0 in both environments.

I tried the Ascorbic Acid test on the Eye Ball escutcheon (it is quite yellow). The stain disappeared IMMEDIATELY!!!!


So ---- now I know what to do ----- but being who I am and the way I am , ----- I still want to know why the switch to Ultra Bleach caused the problem. And since I have no Copper or Iron ----- What the heck is it?

BTW the reason I keep the eyeballs tight is because the Robot takes them off and eats them !!!! (Hungry little bugger)

Here are the numbers for today:

Water Temp 83
pH 7.5 by titration
FC 5.8 ppm (FAS-DPD)
TC 5.8 ppm (FAS-DPD)
CC 0 ppm (FAS-DPD)
TA 80 ppm (by titration)
CH 240 ppm (by titration)
Phosphates 200 ppm
CYA = 50 ?? (turbidimetric) depending on who looks at it --- I HATE THIS TEST!!!!

[chem geek]

So ---- now I know what to do ----- but being who I am and the way I am , ----- I still want to know why the switch to Ultra Bleach caused the problem. And since I have no Copper or Iron ----- What the heck is it?

Marie (mbar) is an expert in stains so could probably help explain this with more real-world experience than I (so perhaps you should re-post your question in the Stains and Metal Matters forum), but it is known chemically that higher pH precipitates metals out of water and can therefore cause staining. Bleach is somewhat high in pH at 11 and Ultra Bleach may be slightly higher due to somewhat higher chlorine content (6-7.35% for Ultra vs. 6.15% for Regular Clorox bleach). Chlorinating liquid at 12.5% sodium hypochlorite concentration is even higher in pH at around 13.

When you add the chlorine to your pool, this higher pH may precipitate the metals in the region where the chlorine is "spreading out" from where you pour it. Eventually, though, the dilution of the chlorine in the total pool water volume will lower its pH below the level where precipitation will occur. If this is what was happening to you, then I would expect most of the staining to occur wherever it is you poured your chlorine. Is that the case? As for why no iron or copper is measured in the water, perhaps you precipitated it all out from the use of the chlorine -- either that or the stain is something other than copper or iron (a true mystery!).

Richard

[Jakebear]

Hi Richard,
Yep --- a mystery. The stain was noticed on the steps and skimmer boxes when we lowered the water level about 3' (1500 gallons) working on getting the CYA down. (it's working slowly but-----). Like I've mentioned the liquid bleach was the only (apparent) change.

I pour the bleach in at the return stream about a foot from the edge at the three jets. Then stand on the diving board and spray (pitch) the remainder out across the surface of the deep end of the pool.

The stain is not localized so I doubt it is a result of direct contact.

I'm making preparations to do the stain removal (L-Ascorbic Acid) and metal chelating removal process (Versine Acid EDTA [from the MSDS]) . I just can't figure what chemicals are part of the reaction that caused the stain(which is why I posted here).

[mbar]

I was just reading this post, and I am as surprised as all of you as to why switching to bleach would cause this problem. I have found the complete opposite - cal hypo usually brings the stains out in my fiberglass pool. This is the way stains form in my experience. When there are any metals in the water - and metals come from dust, fertilizer, and who knows what else, even calcium is a metal, so even though the water doesn't test that metals are present in the water idoes not mean that aren't any. I never have metals show up in my tests, yet I get stains on my fiberglass pool if there isn't enough sequestering agent in the water no matter what I do. The fact that it is only on your return jets and skimmer is not a surprise to me, as these are made out of fiberglass (steps) and plastic. I read on a fiberglass website that fiberglass is magnetic, and it can draw out any metal that is in the water (I don't know if this is really true, but it may be why fiberglass stains and plates more than other pools). So if this is the case , then maybe it is why you only got stains on these parts of your pool. I know that the stain forms when the high chlorine reacts with high ph, and any metal that comes in contact with this solution will fall out. I can't answer why the calhypo never did this in your pool and bleach does, but it may have to do with the ph of the bleach. I have found that everyones water in the pool is different, and can react differently with different chemicals. There is just something a little different that is reacting with something else - So I understand why you want to know what it is. Sorry I can't help with that. Let us know if you do figure it out, so we can learn and help others.

You may just want to lower your ph to 7.2, and add a sequestering agent and see if the stains come off. If you do decide to do the ascorbic acid, you shouldn't need a lot, and you can start to bring up your chlorine right away. Just keep your ph low while raising the chlorine.

If you don't like the bleach, you can always swith back to what you were using before - if it ain't broke don't fix it

[Jakebear]

Hi Marie, (If you want to move this to the stain side --- go ahead)

Like I said to Richard --- It's a mystery!! I was just getting ready to post on the stain forum --- when I came to clip the thread URL --- Here you are!!

I keep trying to think what the cause is but obviously I'm not getting any where. Over the last 4 years we have tried all the JUNK (before we found this site) including Nature 2, Pool Genie, various sundry of cleaners and chlorine mixes etc. etc. so who knows what's left hanging around from the past. That said --- none of the "junk" has been present this season (except for residual).

As mentioned I'm dropping the Cl etc. to get ready for the Ascorbic acid which will get followed up with the Chelating agent --- Hopefully all without going to green, pink, yellow or black. I'll keep you posted.