Crazy Pool Readings! URGENT HELP REQUIRED ! PLEASE HELP!!!

Hi,

Please could someone help.

I live in london, uk and have had crystal clear waters in my pool (approx 79000l) all summer. However after a recent pool party and my adding of chlorine and ph adjusters, the chemical readings are very strange. I was having difficulty understanding the readings using normal dye tests so went out and bought a SCUBA II digital reader to provide more accurate readings.

The readings I currently have are
PH7.4
Free Chlorine - My meter just says HIGH i.e. above measurable range
Total Chlorine - My meter just says HIGH i.e. above measurable range
Cyuranic Acid = 114
Total Alkalinity = 268

The pool has a turquoise / green tinge to it, there is some residue on the sides of the pool. Having said that it was just about useable today... even though it was no where near its crystal clear blue normal self.

The pool has a vinyl liner and an air source heat pump, with water heated to 30 degrees celcius.

Do I need to wait for chlorine levels to drop over a period of time?
Should I partially drain the pool?
Should I isolate / turn off the heat pump to avoid any damage due to high alkalinity?

I normally used stabilised chlorine granules to santise along with chlorine tablets in the skimmer.

Really hope somebody can help with meaningful advice. I would prefer not to drain the pool as it is so large to refill, but will do so if there is no alternative.

Hope you can help!!

S

Hi Stan!
Sometimes, it's hard for us to help those outside North America, because some of the test kits and chemicals are very different. Can you get a simple OTO/Phenol Red test kit? Color matching tests CAN be tough to interpret but drop-testing is usually more accurate and easier. For example, the FC test goes from red or pink to crystal clear. The Total Alkalinity test goes from green to red. Ben, our site's owner, is very leery of ORP testers. I know little about them but they have to be calibrated frequently.

Your pH is OK, FC and TC don't tell us anything because we don't know what the limit of the normal range is. You can double whatever that range is, probably, by mixing pool water and distilled water half and half and testing the dilute mixture. CYA is very high. I'll bet anything you're using Di-chlor powder and Tri-chlor tablets. Stop. They have elevated your Cyanuric Acid (CYA) to a difficult range. And your Total Alkalinity number seems extremely high to me. Have you been adding a lot of baking soda to it? Do you have a Hardness measure as well? It's usually not relevant to vinyl pools unless extremely high.

At a guess, you have an algae bloom. The solution is not complex. You'll have to raise your chlorine level to a sufficient degree and keep it raised till the algae is dead. If your CYA reading is accurate, that means to an FC level of no less than 25ppm. It will take several days or more. You can use two chlorine sources. The first is our first choice, always: Bleach. Ordinary, unscented, house-hold bleach, the stronger the better. Liquid Chlorine, sold in pool stores here across the pond, is the same thing, only stronger. Here, "ultra" bleach is available in an 8.25% concentration. LC can be 12.5-14%. It's all called "Sodium hypochlorite". Alternatively, if your hardness level is low, the lower the better, you can use Cal-Hypo powder--calcium hypochlorite. Cal-Hypo doesn't add CYA but does add calcium. Again, if you're not getting close to 400ppm (hardness) it's not a problem.

How much? While we figure in US gallons here, the ratios are the same. Here's the rule of thumb for bleach: If the concentration is 8.25%, one liter of bleach will add 8.25ppm of chlorine to 10,000 liters of water. But it will take two liters of 8.25% bleach to add 8.25ppm of FC to 20,000 liters. So you'd need ROUGHLY 8 liters of 8.25% bleach to raise your pool by 8.25ppm. That works for any concentration--5.25% adds 5.25ppm, 14% adds 14ppm.

Not sure I can do the conversion on Cal-hypo so well, but I estimate that 325 grams of 65% Cal-Hypo powder will add 10ppm of chlorine to 79,500 liters of water + 7-8ppm of calcium.

Meanwhile, read our various forums on dealing with algae, and go to our sister site, PoolSolutions.com and read everything you can.

That's just for starters.

Good luck!

Thanks Carl.

Appreciate the advice. The pool meter that I have is meant to be quite accurate...
http://www.lovibondwater.com/product/scuba-ii.aspx

The Chlorine level reaches up to 6mg /l so we know that chlorine level is higher than this. I will try your method of diluting the water to get an proper chlorine reading.
I have read that my Cyunaric acid levels should be no more than 100 ppm, so although mine are high... they may not be exceptionally high.
Yes I have been adding some kind of baking soda to help stabilise ph.

A local pool person has suggested the following

- Keep the pool cover off to help the sunlight breakdown the high chlorine
- Brush the Algae so that it combines with the free chlorine in the water
- Add some fresh water where possible to help dilute
- Drain a little of the old water where possible to help dilute

He suggested doing the above before adding any more chemicals. Do you think this is a sensible approach?

Many thanks!

Hi Stan!

Stop adding baking soda. It's not doing you any good and it's raised your Total Alkalinity into a very,very high level.
I don't know how 6 mg/l translates to ppm though this converter I found seems to indicate they are almost the same thing. So your FC measure tops at 6...and you need to get it 25!
Try diluting 3 parts of steam distilled water to 1 part of pool water and see where the meter reads it--then quadruple the reading. If it doesn't hit the "HIGH" mark you need more chlorine.

Here's what I think of your pool guy's advice: Most of it's not going to do any good.

CYA of 100ppm means you need to MAINTAIN a free chlorine level of between 8 and 15ppm, and you need to shock at 25ppm. Lowering your FC before your algae is dead is not going to work.

Pool guy's advice:
While sunlight will break down chlorine, when CYA is over 100ppm, it won't do much, especially since you are at such a high latitude that the sun is much weaker. CYA is like sunscreen for chlorine, and you've got an excess of "sunscreen". It's also NOT what you want to do re: algae.
Brush the walls and floor of you pool to knock the algae loose. Yeah, that's good advice. Do it every day, but if you aren't going to raise your chlorine it won't help.
Fresh water won't hurt, but the only things YOU should want to dilute are you high CYA and TA levels. To cut your CYA in half you need to replace half your water.

The first won't help (probabaly won't hurt), the 2nd is good, and the last two are like trying to dig a coal mine with a teaspoon. Gonna need a LOT bigger shovel!

http://www.unitconversion.org/concen...onversion.html

Carl

Really appreciate your help. Sorry to ask further questions... but you seem to have greater knowledge than me.

1) My current chlorine level is above 6 (my meter only reads up to 6), but we can conclude it is very high! If I add more chlorine as you suggest, will that not make my chlorine exceptionally high.... it will take over a month for the chlorine to return to normal levels no?
2) Adding more chlorine will not reduce my CYA level, or improve my alkalinity level. So I will still have CYA of well over a 100 no?
3) Can I not try adding some Algaecide instead as an alternative to shock chlorine? This would prevent the need for me to reach epic levels of chlorine no? Just worried as my meters normal range stops at 6 and yet you are suggesting shocking to 25 ppm. Seems really high to me... I wouldnt be able to use it for ages right?

Sorry to ask further questions

S

Stan,

Check our sister site for lots of great information on the relationship of chlorine to stabilizer and how to test:

http://poolsolutions.com
http://poolsolutions.com/gd/best-gue...ine-chart.html

1) You need to know WHERE your chlorine actually is. Try using the dilution method to get an estimate. If your tool reads "HIGH" when you've diluted 1:1, then your FC is over 12. If it reads "HIGH" when you've diluted 1:2 (1 pool to 2 distilled) then your FC is over 18. Etc.

You are worrying about chlorine levels being too high when your PROBLEM is algae keeping your pool green and keeping your water for being sanitary. It's like the old joke:
"When you are up to your (waist) in alligators, it's hard to remember that the objective was to drain the swamp". You've got alligators (algae) and you're worried about the swamp.

2) Chlorine does not affect CYA or alkalinity levels. If you want lower CYA you must remove and replace water. So if your CYA is 100, you need to drain off and replace half your water to drop it to 50. Total alkalinity is lowered by lowering pH, then aerating the water to raise pH without raising TA--that's a discussion for when you're rid of the "alligators"!

3) There is only one algaecide we recommend and that's mainly as a preventative, not a cure. That's Polyquat 60%. Everything else has ammonia and/or copper and or bromine and cause far more trouble than they are worth. Look at the table I referenced--the "Best Guess" table. 25ppm is ONLY high if your CYA is low. CYA is a two-edged sword that protects your chlorine from breaking down in UV rays but also slows down its effectiveness. Handled properly, it can be a boon, handled incorrectly a bane. High CYA and correspondingly high FC levels can keep a pool from losing chlorine in hot, sunny climates. Some pool service companies use CYA=100 so they only have to show up once a week because the chlorine holds. Some of our members in hot states keep CYA = 80 and maintain their FC between 5 and 10ppm.

If your CYA was between 10 and 20ppm, you'd be shocking at 12ppm of FC, not 25ppm.

Once you get your algae clear, you'll need to keep your FC between 8 and 15, just for maintenance! Yup. That's really true. And yes, you can safely swim in it when the FC is that high--because the CYA is that high. You can even swim in it when it's 25--as long as the algae is dead and it's clean. It won't hurt your skin but if it's 25 wear older bathing suits because they made fade.

Until your registration is completed, you won't be able to see the rest of the forum or follow links while you are logged in. So, copy those links that Carl gave you and paste them into a browser window after you first log out.

(Use this one http://pool9.net/cl-cya/ instead of the second one that Carl gave you.)

Hi Carl.

Many thanks for taking the time to reply to my mail. Your help is greatly appreciated. Your comment about alligators was very funny. The worst we can expect in the UK are frogs in the pool... certainly no alligators. Apologies for the delay is responding been busy with family and reading your excellent pool solutions website.

1) I have used your dilution method to measure the Free Chlorine in the water and I believe it to be 10.4.

2) I have also lowered the pool water by approx 20 to 30 %. I hear you when you say that this is not going to make a huge difference, but I had started the process, so I let it run for a while. I am now refilling the water and expect this to be complete in a day or so. Also my pool line is really old and faded, so don't want to fade it anymore. My kids also have sensitive skin.

3) You would not believe the hundreds of pounds I have wasted on expensive pool chemicals in previous years. Your pool solutions website is a revelations! I have been hunting high and low for the last few days for cheap bleach. Sadly in the UK most bleach comes with foaming agents or fragrance. This is the only variety that I have found that looks suitable....

http://www.tesco.com/groceries/produ.../?id=260550096

On the plus side it is cheaper than bottled water! On the negative side.. it is only 1.5% so I have had to buy all the store stock! So I have 13 bottles (26 litres). I will need probably the same amount again to finish the job. No big deal, just means I will need to hit another branch of the same supermarket later in the week.

4) The plan is to let the pool water level return to normal. Retest for FC, TA, CYA, PH etc Get the pump going and use the supermarket bleach ASAP. I did by some Algaecide a week ago, but having read your email I have decided to leave it well alone for now.

5) I believe my bottom drain to be blocked, so I am dependent on my skimmer basket return. Water pressure at the sand filter is very good. There seems to be no visible means of playing with the bottom drain. I may try a drain snake when the algae is gone.

6) I skimmed an article you wrote about lowering TA. It said I needed to aerate the water... pardon my ignorance, but my haywards multiport valve has no such option. Do you mean filter? Below is a link to a pici of the type of valve I have.

http://yourpool.co/running/what-do-a...g-actually-do/

Below is a pici of my pool just before I started draining.

http://s46.photobucket.com/user/stan...a44ad.jpg.html


Many thanks again!

S

Quote:

---

Originally Posted by stantheman

Hi Carl.

Many thanks for taking the time to reply to my mail. Your help is greatly appreciated. Your comment about alligators was very funny. The worst we can expect in the UK are frogs in the pool... certainly no alligators. Apologies for the delay is responding been busy with family and reading your excellent pool solutions website.

1) I have used your dilution method to measure the Free Chlorine in the water and I believe it to be 10.4.

That's probably good enough. I never measure closer than .5...10, 10.5, 11, etc.

2) I have also lowered the pool water by approx 20 to 30 %. I hear you when you say that this is not going to make a huge difference, but I had started the process, so I let it run for a while. I am now refilling the water and expect this to be complete in a day or so. Also my pool line is really old and faded, so don't want to fade it anymore. My kids also have sensitive skin.

20 to 30% means you'll lower CYA by 20-30%, which will help. There's lots of discussion of what REALLY bothers skin. All evidence is that it's not the Free Chlorine, even when it's very, very high, but rather the Combined Chloramines that are irritating to skin and eyes--which is why the IDEAL CC level is...zero. The next thing you need to remember is that "high chlorine" is only high relative to CYA. So when your CYA is over 100, the recommended FC level of 8 to 15 is actually no higher RELATIVELY, than an FC level of 2-5ppm is when CYA is under 30ppm!

If you look up the thread I started recently on liner fade, you can see how much my liner faded in 12 years (rebuilding the pool now). Fading happens.

3) You would not believe the hundreds of pounds I have wasted on expensive pool chemicals in previous years. Your pool solutions website is a revelations! I have been hunting high and low for the last few days for cheap bleach. Sadly in the UK most bleach comes with foaming agents or fragrance. This is the only variety that I have found that looks suitable....

http://www.tesco.com/groceries/produ.../?id=260550096

On the plus side it is cheaper than bottled water! On the negative side.. it is only 1.5% so I have had to buy all the store stock! So I have 13 bottles (26 litres). I will need probably the same amount again to finish the job. No big deal, just means I will need to hit another branch of the same supermarket later in the week.

I'm confused: The description says "less than 5%" yet it seems to be only 1.5%.. Are there no pool stores that sell "Liquid Chlorine"? You can test the stuff easily. All you need is an eyedropper with a 1ml marking. Fill a bucket with 10l of tap water. Test its chlorine level. Then add 1ml of bleach to the bucket and mix. Measure chlorine level again, and subtract the tap water's chlorine level. What's left is a good estimate of the ACTUAL strength of the bleach.

But you're wise to avoid the sudsing, frangrances, etc. They WILL give you problems!


4) The plan is to let the pool water level return to normal. Retest for FC, TA, CYA, PH etc Get the pump going and use the supermarket bleach ASAP. I did by some Algaecide a week ago, but having read your email I have decided to leave it well alone for now.

If it's not Polyquat, don't use it.

5) I believe my bottom drain to be blocked, so I am dependent on my skimmer basket return. Water pressure at the sand filter is very good. There seems to be no visible means of playing with the bottom drain. I may try a drain snake when the algae is gone.

It could also be, now, a place where the algae is congregating.

6) I skimmed an article you wrote about lowering TA. It said I needed to aerate the water... pardon my ignorance, but my haywards multiport valve has no such option. Do you mean filter? Below is a link to a pici of the type of valve I have.

Whoops! Aeration is merely exposing lots of water to air. You can mount a fountain (I have one that screws into my return) or point the returns at the surface so they splash. Since the water isn't yet safe to swim in, you miss out on the best method: A gang of kids going crazy and splashing! Yup, that's all it is...Nothing to do with your multiport valve.


http://yourpool.co/running/what-do-a...g-actually-do/

Below is a pici of my pool just before I started draining.

http://s46.photobucket.com/user/stan...a44ad.jpg.html


Many thanks again!

S

---

Nice looking pool! I see the liner has pulled out of the corner near the diving board. There's a plastic strip you force into the corner when the liner is in place called "Liner Lock" that prevents that.

Thanks again Carl!

Some recent updates..

So I refilled my pool and took some fresh readings on the 15th Sept

8th Sept PH7.4 FC 10.4 CYA 114 TA 268 (Before any action)
15th Sept PH7.3 FC 6.8 CYA 82 TA 238 (After draining pool 20% and refilling with fresh water)

I then added 26 litres of 1.5% Sodium Hypochlorite bleach from my supermarket

I waited 24 hours and checked FC...

16th Sept FC 11.2. The pool was / is still green

Clearly the volume of bleach was not enough....so I ordered some 14/15% chlorine shock (liquid). This should arrive anyday...
If it arrives today, I will add it today... The only question is.... how much! :)


I have looked into getting a pool fountain and will be persuing this! :) Kids will love it.

Regarding the slipped liner... and Line Lock... again I will look into this... but how do you pull the liner back into the right place? I have tried using hot water but this didnt help. Any suggestions?

Many thanks

S

Hi Stan,

With your new readings, your target FC level is 20, based on your CYA. In my first post I gave you the amounts of chlorine to add to achieve certain levels. That's based STRICTLY on the volume of water--79k liters. So it doesn't change unless the volume changes, regardless.

Look at the Best Guess Table:
http://poolsolutions.com/gd/best-gue...ine-chart.html

While we measure everything in gallons, if you transpose to liters the ratios remain the same: 1 liter of 14% Liquid chlorine/bleach will add 14ppm of FC to 10,000 liters. 1 liter of 6% will add 6ppm to 10,000 liters. Since you have nearly 80,000 liters, you need nearly 8x as much liquid chlorine/bleach to get the same effect.

Once you get your FC to 20, you'll need to keep it there, checking and adjusting chlorine 3x/day to keep it at 20ppm. Meanwhile you need to vacuum and brush your pool daily, and expect it to take several days to a week to clear up. When the FC does NOT drop overnight by more than a little, for 2 nights running, and the water stays clear, you'll know you're done.

Hi Carl

Hope you are well.

Since my last reading, I have done the following

1) I have added 20 litres of 14% sodium hypochlorite over a period of 2 - 3 days e.g. 10 litres first night, 5 the second and 5 the third. (I figure that this should have kept my FC levels well over the 20 mark for a couple of days).

2) There was no real change in the colour of the water after this period, it still looked green.
So i then went to the supermarket and bought some bleach and I added 26 litres of 1.5% bleach.

Soon after this, the water started to become lighter in colour... and I left the water alone for a couple of days.

Today, the water looked pretty good (not clear though) so we took a swim, and then I re-took some readings.
28th Sept. I also backwashed this morning.

FC = 13.2
PH = 7.6
CYA = 76
TA = 230

Below is a link to a photo of the pool. As you can see the green Algae seems to have gone, but the water is still not quite right. Certainly not clear. Any suggestions??


http://s46.photobucket.com/user/stan...f2c1a.jpg.html

Do I shock again? I have 2 X 5litres of 14-15% bleach ready to go.... thought I would check with yourself.

We are having some awesome weather for late September in London. Normally it is time to get the big coats out, but we have had blue skies recently.

Many thanks

S

Stan, It is hard to tell, but your water looks cloudy, but I think your algae bloom is dead.
So what I think is going in is one of two things, maybe both.
(you never did give us a hardness/calcium hardness reading, did you?)
1) Dead algae which means you need to run your filter 24/7 and clean it out when the pressure rises. I don't know if they sell "skimmer socks" in the UK, but if not you can line your skimmer with a piece of ladies' pantyhose. It can help pulling particles out. If you have a sand filter you can add a little DE powder, just enough to raise pump pressure 1 psi. All this is to filter dead algae.
2) You could also have calcium clouding, depending on your calcium hardness reading, given your total alkalinity is so high. Try lowering your pH to 7.2 ( no lower as it may be overstated by your chlorine level) and see jf that helps. Follow our method for lowering T/A to get it down to around 100 and see if the water clears. A very high T/A, over 200, and a high CH, 400-500 ppm can cause milky cloudy water. It isn't dangerous but it is ugly.

Again, either could cause cloudiness.