Switched from Cal Hypo to Bleach

[DavidD]

Rest assured, It's not the bleach! There is now difference between the bleach and pucks except the bleach is higher in PH and has no CYA. As previously posted, sounds like minerals. At a higher PH, they will drop out but your PH seems perfect.

Dave

[Jakebear]

I've read over and over ---- Bleach is Bleach --- Chlorine is Chlorine and I accept most of that.

This is NOT an new pool --- We have had this pool 4 years and used Cal Hypo since it was new --- NO STAIN --- 2 weeks into usiing Sodium Hypochlorite and we have stains ---- There has to be a correlation to the reaction or chemical composition of the Sodium Hypochlorite ----- and a preventative measure.

I'm really more concerned with that aspect than I am with the stain which is why I posted to this forum instead of stains etc.

EDIT: Also the pH has been stable with no muriatic being necessary

[waste]

Jakebear, while I may not be the 'go to' person for this on the forum, a possible cause suggests itself. #1, have you ever noticed the same thing on your return jets, before the changeover? (esp the inside of the 'eyeballs'). [I'll assume a 'yes' answer and continue]. You said that "the only real change is the bleach", I beg to differ, another change is that you have been replacing 500 - 1000 gal every other day with well water. What I suspect is that you have a small amount of metal in your well water, small enough to have gone unnoticed with just regular 'top-offs' in the past and now you have increased the 'normal' amount in your pool by purposly increasing the concentration of well water in your pool.
With that said, there is a difference between the different types of chlorine routinely applied to a swimming pool; the concentration and delivery method. I don't know how you've added the dichlor and cal hypo in the past, but I think that it never came in close (concentrated) contact with the areas you now find to be staining. Bleach, on the other hand is usually poured directly into the pool, and I know that when I add it, I pay extra attention to the returns, stairs and suction areas - if you do the same, you have a 'plug' of highly chlorinated water in these areas and high chlorine will precipitate the metal out of the water.
But you asked for a solution:
Take some tap water down to a pool store and have it tested for metals, I truely think you'll find some. If you do have metals in the fill water, always add a sequesterant before adding the fill water (please see the 'stains and metals' section for more expertise advice). I may be way off, but I've given you the best that I can - Welcome to the forum!! - Waste

[Jakebear]

Hi Waste,

Thanks for the observations.
Let me address the points one at a time.
1. I have regularly removed the eyeballs in order to reposition the direction of flow (they are tight so they have to be disassembled to change. There has never been any noticeable stain or deposit seen there.
2. When we got the pool installed 4 years ago the pool company shorted us about 4000 gallons on the initial fill and we used the well to finish that fill. Since then we have regularly added thousands of gallons of water from the well every year to replace splash out and evaporation. The pool holds about 500 gallons to the inch so it has been easy to keep track of how much has been added.
3. As mentioned in the initial post we discontinued using pucks, on 6-24-06 to be exact (I keep very careful records in the form of an Excel Spreadsheet – every test – every treatment and setting). On the July 1, 2006 we started using Cal Hypo granules at the rate of 12 oz being equal to 1 gal bleach – in conjunction with Michael's bleach calculator to determine the dose. We did this until we discovered (with the help of y’all on this forum) that the Cal Hypo was causing the cloudiness that would not go away (see my posts back around 2 weeks ago). We took Carl’s advise and quit with the Cal Hypo and switched to bleach. The pool cleared immediately and all has been good until we noticed the stain yesterday.
4. I have taken samples to be analyzed but not to the pool store. They once told me I had CYA in the well water (another long story that’s 2 years old). To make a long story short I don’t trust them ---- period. I was looking at a water softener a while back and was told I didn’t need one and there was very little iron in the water. That was a while ago so maybe things have changed.

Lastly --- some of the other comments and posts in the “stain” section recommend using Ascorbic Acid. The instructions on the container I got says to lower the free Chlorine to between 1 and 2 ppm before using. Now with the CYA above 50 I hesitate to do that either.

I guess you could say we’re caught between the devil and the deep!!!

[waste]

Jake, HA! I was right on at least 2 things - I'm not the 'go to'guy here and, as I said, I may be way off! So there!
Sorry, I really thought I had a good possible solution, unfortunately, your pool doesn't agree with, an otherwise excellent, assesment. I'll keep my eye on this and if none of the real 'go to' guys answer, I'll pm them and try to get you their oppinion. As I said, I gave it my best, good luck with finding the cause and solution.

[waste]

Jakebear, let me take one more stab at this before I call in the pros. Are these areas gritty, feels almost like sand? If so, you've calcified your pool (aka scale), and will need to adjust the pH and alk to alieviate the problem (though a look at your numbers scaling doesn't fit ).
You can use the ascorbic acid to test for metal stains without having to treat the whole pool - place a big ol' pinch in a stocking and rub at a small portion of the stain for a minute, if it lightens then the stain is metal. If that shows no results, try the same using some of the powdered shock, but let it sit for an hour (Trichlor pucks are also good for this) - this tests for organics. Finding out the type of stain is the first step in treating it.
While I'm at it, why do you keep the return 'eyeballs' so tight? They work just fine without being 'reefed in' and it's much easier to change the direction of them.

[DavidD]

Jake,

Waste assessment is pretty good in my opinion, the only thing you've changed is the method of delivery per se. I have seen the plastic on eyeballs, skimmers and steps turn a yellowish color before. I believe there are few things that can cause this besides metal stains and scaling. Not to say that these apply to you but they are extremely low PH, UV and copper. The pool that I'm referring is an above ground and they used Pristine Blue for a few seasons. My friend told me that they noticed the change in color after a few months of use and when I tested their water, sure enough the PH was less than 6.8! I also tested for copper and it was above 1ppm so we drained and refilled.

Now, for the ascorbic acid, have you tested a spot yet? If not, that is the first thing to do. You can test using a Vitamin C tablet, cheaper the brand the better. If it does work, dose your pool with polyquat (a.k.a. Algaecide 60%) to help ward of the green and go for it. You can bring the chlorine back up slowly in a few days. Be sure to follow the recommendations in the Stain section, paying close attention to all post by mbar. Marie helped me out tremendously with my in ground fiberglass pools a few years back. I generally treat my pool a couple of times a season with the ascorbic acid and by the way, the pool store tells me I have no metals as well. For some reason though, I get these grey stains and the ascorbic does the trick.

Dave

[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