Am I Super-Shocked (30 PPM enough) ?

[paul6585]

Sorry for long post but wanted to include as much relevant info as possible.

At my wits end buying bleach and “liquid shock”. Sixth season with this pool and I do all maintenance including open/close. It opens dark brown every year but never had a problem like this. Its still Green and adding sodium hypochlorite is not clearing it up. I can see bottom of shallow end but have not seen drain in deep end yet this year. I am seeking your help. Read on Please.

Initially shocked it with two gallons of sodium hypochorite 12% about one month ago (May 26th) and had progress but never totally cleared. It went from dark brown to light green in about one week. Until about ten days ago I also used pool store chemicals they recommended:
“Fresh & Clear Oxidizing Shock” = Potasium Peroxymonosulfate 38%, and “Chlor Brite” =Sodium dichlor-s- Triazinetrione di-hydrate 99%.
I have lost confidence in the pool store test results and recommendations. I think they were getting false TC=FC. I have had a few of those myself with the same Taylor kit they are using.
Fyi – skimmer tabs were also present during first 3 weeks of operation. Not sure exact composition but approx. 20 were consumed.
As a side note, I over did it with Baking Soda to get the TA up during the first week and had to add 4 gal of muriatic acid. TA is fine now as of about two weeks ago.

I always use Borax for pH up.

I am now trying to get back to BBB method or what ever will work properly to clear the water.

Last week, (prior to purchasing test kit) I shocked twice with 4 gal. of 12% sodium hypochorite about two days apart with no results.

After testing several water samples the past week and adding many gallons of “liquid shock”(12%) and Bleach (6%), I cannot seem to get the FC up.
I am Using Taylor Kit K-2005 (sold at local pool store). I called Taylor and it is same as K-2006 but without Titration for Cl. My TC readings have been equal to or higher than the 5 PPM comparator window in my kit so I am diluting the pool water sample in half using distilled water, comparing, then multiplying result x 2. I used OTO test kit to ensure Cl readings were not off the chart and being “bleached out”. OTO is pale yellow indicating less than 1 PPM. I assume this is FC. after about 1 minute it turns darker yellow but not orange. I read OTO is not accurate over short amount of time but is good for indicating excessive chlorine amounts if it turns orange.

I read on another website that 10x the amount of CC is needed in the form of FC to get rid of (convert?) the CC. With CC readings of 5 PPM (see below) I would require 50PPM FC. I did NOT shock to 50 PPM but I shocked to 30 PPM at 1 am this morning (it was dark outside) per my test kit manual part # 2004B, Table B - “30 ppm Shock Table for Algae Removal” which suggests 15 gallons of bleach (6%); ie. Table has 10k gal @12% Cl= 2.5 gal. So for my 27k gal. pool: (2.5gal x3 {rounding for 30k gal} x 2 for 6%) = 15gal.

This morning (10:00 am) pool was still green so I back-washed, added more DE and brushed entire pool to stir things up. Still Green as of 4 pm today (Fri, 6/24/11)

In summary TC has been 6 to 8 and FC has been 0.5 to 3.0 giving me CC of approx. 5ppm consistently.

I do have confidence in my filter and pump.

pH 7-2 to 7.3 (consistently)
TA = 85 consistently
CYA = 30 consisitently

Having no visual results 14 hours after shocking to 30 PPM I am concerned. Maybe I'm being impatient but I am concerned I did not shock hard enough.

Questions:

1. Should I have seen results by now? How long before visual results?
2. Do I need to keep testing?
3. How do I get the FC up?
4. Did I sell myself short by following the manual to “super-shock” at 30 PPM instead of 50 PPM (10x 5 PPM CC) and did I calculate amount of chlorine (15 gallons of 6% bleach) correctly?
5. Is sodium hypochlorite found in bleach “free Chlorine”?
6. Is CYA test method in Taylor kits accurate? Ie “When black dot disappears…”
7. How much bleach is too much ie concerning damage to liner?
8. Is there a more efficient method to “oxidize” the CC to get FC?

Please provide your feedback / recommendations. Your help is appreciated.

paul

[Watermom]

1. Maybe or maybe not. Don't know how long for sure. But, what I can tell you is that with a CYA of 30, you need to shock to 15ppm and try and hold it there without letting it yo-yo up and down. I can't tell from your post if that is what is happening. You need to sustain the high cl reading. As many times a day as you can, test the cl level and each time add enough chlorine to get back to 15. There is no such thing as testing and dosing with chlorine too often when you are fighting algae. The more times and the more often the faster it will clear. For reference-- in a 27K pool, each gallon (4 quarts) of 6% bleach will add 2.2ppm of cl. Run the pump 24/7 and backwash as needed.

2. YES. See above.

3. See #1.

4. No. Shocking to 15 should be sufficient with a CYA of 30. (If you haven't already seen it, look at the Best Guess chart in my signature below. for the connection between CYA and chlorine levels.) You do not have to shock to 10x the CC level.

5. Any form of chlorine is free chlorine which is chlorine which is available to sanitize a pool. Bleach works great at killing algae if you consistently maintain shock level.

6. Yes.

7. See Best Guess Chart.

8. No. Consistent high levels of chlorine are what you need.


One other thing, since you have the K-2005, you can just pick up a K-1515 and you will have the component which is in the K-2006 that allows you to measure high cl. You can pick one up through the Amazon link in my signature below. I suggest that you do so. It will make pool maintenance much easier for you. The dilution method works for a temporary fix but isn't super accurate.

Hope this helps. Welcome to the Pool Forum and thanks for becoming a subscriber.

(I'm not familiar with Fresh & Clear Oxidizing Shock = Potasium Peroxymonosulfate 38%, and how it might be playing into your saga. I'm going to check with Ben about that.)

[PoolDoc]

Hi Paul;

Lisa's responded to your questions.

But my impression is that you haven't consistently done anything. Is that right?

Algae will regrow rapidly. Essentially, once a pool is green, you are either winning or you are losing.

To win, you have to win consistently, without missing a beat, till the pool is clear. Otherwise, the algae just regrows, and you slide back to where you were, wasting all the chemicals used so far.

If you want me to look further at what happened over the past month, I need a chart that shows daily levels, conditions and doses. Otherwise, let's just start with where you are -- from scratch.

#1 - Get an FAS-DPD add-on, or a K2006.
#2 - Use borax to raise your pH to 7.6 or so.
#3 - Use bleach -- added within 2 hours of sunset -- to maintain a strong yellow 'flash' (initial) OTO reading. Only back off if it goes a dark orange after 1 minute.
#4 - Borax and bleach -- nothing else, for now.
#5 - Test chlorine levels 1 hour after dosing, and again early in the AM, and then again just before dosing the following day. Tell us what those readings are.
#6 - Run your filter 24/7; clean as needed but no more than that.
#7 - Give us the basic information on your pool: gallons (27K?), type of filter (DE?), type of surface, etc.
#8 - Once you get the DPD-FAS testing, tell us what your real chlorine levels are.
#9 - Do not mix and match advice; go with BBB or the pool store, but not both.
#10 - If you do it our way, NO GOOP! We need to go a couple of days with simple chemistry, so we can see what's happening.

Do this, and we can probably get you cleared up by next week end, especially if you have a DE filter.

Good luck.

[paul6585]

Ben, Watermom,

(pool info is in my signature)
Thank you for your insight and prompt response. I am happy to report that by following your instructions my pool was crystal clear within 48 hrs. You helped turn a very aggravating experience into a pleasurable one. My water is the clearest its ever been.

I think the pH increase was a key factor (up from 7.2 to 7.6). Once pH was near 7.6 on Saturday afternoon I saw immediate progressive changes. fyi - I used soda ash instead of the usual Borax which I normally use.

I am including data for the past 72 hrs so that you can see any trends. At this time my concern is FC& TC are not holding over night.

Additionally, I would like to stop 24/7 filtration as I normally run filter only 6 hrs per day during the season. (My pool gets very little use.)

Qs:
1. Water is crystal clear. Can I resume “normal” maintenance at this time?
2. What are people doing to maintain chlorine and stabilizer or are they adding CYA and bleach throughout the week? I normally use skimmer tabs.
3. FC & TC not holding overnight. Is this normal?

Please review data and comment.

Friday
• 4:00pm TA=85 CYA=30 pH=7.2
• 8 pm added 4 gal 12% shock
• Unfortunately I cannot find Cl data for Friday evenning

Saturday
• 8:00am pH=7.2 FC=0.5 TC=1.0
• 1-7 pm Added 9 lb Soda Ash
• 8:30 pm pH=7.6 FC=0 TC=1.5
• 9:00 pm added 4 gal 12% shock
• 10:00 pm pH=7.6 FC=10 TC=10 (determined by dilution of FAS)

Sunday
• 8:00 am pH=7.6 FC=0.5 TC=1.5
• 9:00am added 4 gal 12% shock
• 10:00am FC=10 TC=10
• 4:30pm pH=7.5 FC=1.5 TC=1.5, added 1 lb soda ash
• Note by 9:00pm pool was clear
• 9:00pm pH=7.6 FC=0.5 TC=1, Added 1 gal 12% shock
• 10:00pm pH=7.6 FC=6 TC=6

Monday
• 9:00am pH= 7.6 FC=1 TC=2 TA = 110
• 9:00pm CYA=35 pH=7.6 FC=0.5 TC=0.5 added 1 gal 12% shock
• 10:00pm FC=6 TC=6

[Watermom]

Thank you for providing the information.

You are not quite ready yet to go into maintenance mode. You must continue to keep the high cl until you can go from sundown one evening to sunup the next morning without losing more than 1ppm of cl. The fact that you are losing so much overnight means you are still fighting something and need to continue shocking. With a CYA of 35, you need to shock up to 15ppm. Every time you test, add enough chlorine to get back up to 15. In your pool, each gallon (4 quarts) of 12% chlorine will add about 4.4 ppm.

After you are able to pass the overnight test, then you need to maintain your chlorine reading between 3-6 all the time or you'll risk another algae bloom. Since your CYA is only 35, you can use some of the Trichlor pucks for a short time, but when your CYA hits about 50, no more pucks. Stabilizer (CYA) stays in the pool all summer and sometimes even over the winter so you shouldn't have to mess with it any more after it hits 50. (FYI -- For every 10ppm of chlorine that a trichor puck adds, it also adds 6ppm of CYA.)

Your pH and alk are both fine.

You also need to continue with the 24/7 filtration until eveything is all cleared up and you pass the overnight test.

You are getting there. Don't quit too soon or you'll be right back where you started!

Hope this helps.