High CYA in PA

[mikeinoleypa01]

We have been battling high Alkalinity and high CYA since we opened our pool about a month ago.

Currently (using TF Kit we bought online):

FC = 2
CC = 1
TA = 120
CA = 320
CYA = 110

25,500 gallon inground concrete pool. Water temp 78.


Our TA is in much better shape at this point in time. We stopped using calcium based shock and sticks and have been using only Clorox for the last 3 days. Our FC is still going down each day due to the high CYA. We have come to the conclusion that we will need to drain and refill some of the water to stabilize this. What is a good amount of water to drain off. We will need to have a bulk water company do the refill since we our on a well and do not want to put alot of strain on this. Thanks for your help.

Mike

 

[donaldm823]

Re: Hign CYA in PA

if you have an inground pool, be careful about how much you drain. In ground pools in PA see a hydraulic pressure under the pool floor and will rise out of the ground if you take too much water out of the pool. The weight of the water in the pool counteracts the upward push pressure.

I would contact a pool builder and ask, but be wary of draining more that a couple of feet of water. I drop my pool each winter by 1 ft and have no problems. If I ever have to drop it further-I would use an expert as the amount of water safe to drain depends on the local water table and any water springs near your pool. My pool has floor plugs to open the pool floor to the ground water underneath if I ever must drain the pool so as to prevent this hydraulic damage.

 

[Guest]

Re: Hign CYA in PA

It's generally ok to drain a foot below the skimmer.

 

[mikeinoleypa01]

Re: Hign CYA in PA

Guys,
Thanks for the input. Will drain carefully...unless of course there is another option?????

 

[JasonLion]

Re: Hign CYA in PA

You need to replace water, but there are various ways of doing that. You can remove water at the same time you are adding water. This uses slightly more replacement water, but can be faster and is totally safe.

 

[mikeinoleypa01]

Re: Hign CYA in PA

Thanks Jason. Drain and re-fill is a good option. However, since we have a well I am concerned about the strain I will put on the water supply. We deal with a local bulk water company and the plan is to drain off about 5,000 gallons and have them refill for us. This will be happening this week. The bulk water company owner has assured me that their is no CYA in their water (I still may test it before they fill it to make sure).

Mike

 

[duraleigh]

Re: Hign CYA in PA

Mike,

Refilling 5,000 is not enough to get really meaningful results. That will bring your CYA down to around 90ppm, when it should be around 40-60ppm. 10k of refill water will get you to about 65ppm or so. 15k would get you to around 45ppm....that's best but 65ppm is doable. (there is no CYA in water outside of a swimming pool....bulk water folks are correct.

Also, you are very wise not to use your well. Iron is often found in well water and it's a real PITA.

 

[mikeinoleypa01]

Dave - Thanks for your feedback. Can you please let me know the formula you are using for the CYA reduction so I can keep it for future reference. It sounds like I need to drain off between 10,000-15,000 gallons for any results. I can definitely do that. The water guys we deal with have a 6,000 gallon tanker so I can have them do two trips (12,000 gallons). One question - what is the best way to calculate that I have drained 10,000 - 12,000 gallons. Going down just under my water returns is about 5000 gallons; I know that because of the top off I have gotten for the last 4 years. Our pool is irregular in shape - 9ft deep end and 3.5 feet shallow end. Can I just base it on measuring down the same number of feet from the 5,000 mark and estimate that this will be the 10,000 mark?

Mike

 

[JasonLion]

A 5,000 gallon replacement will give you a CYA level around 90, the highest level I would ever suggest allowing. CYA around 90 can be managed with extra effort. A 10,000 gallon replacement will get you to a CYA level of about 65, which is very reasonable. The CYA level will go down slowly over time if you stop using products which add CYA.

The formula for final CYA level is <current CYA level> * <water remaining in pool> / <water originally in pool>. And <water remaining in pool> is <water originally in pool> - <water being replaced>.

 

[mikeinoleypa01]

Thanks Jason for the formula.

Mike

 

[mikeinoleypa01]

We did the drain last week and we have a CYA in the 80-85 range. I was hoping to drain about 10,000 gallons as recommended but we only drained 8,500. It was hard to measure since our pool is irregular in shape. In any event, the chlorine is stabiizing, I can go multiple days without having to add chlorine. We are actually just using Clorox at this point because I am afraid to add anymore Guardex or Bioguard shock that may raise the CYA.

Do you have any recommendations as to adding a chlorine compound to our chlorinator like bleach in a stick form. Do the Clorox toilet disks do the job? Appreciate any recommendations. I do have the dichlor sticks - Bioguard silk sticks but I do not want to use them right now because of the CYA level.

Thanks.
Mike

 

[Guest]

The only form of chlorine you can use in a feeder is trichlor because it is slow dissolving. However, that will cause your CYA to rise. It is not safe to use any other form of chlorine in a feeder.
Trichlor does not play well with other forms of chlorine and to try and use a different chlorine source could lead to an explosion.

 

[mikeinoleypa01]

Three things I am taking away from your response:

1. Trichlor sticks are the only thing I can use in our chlorinator; for now not an option.
2. I should not mix the different forms of chlorine at any time. Do not use trichlor and bleach in any combination. I was not aware of this. I knew it was unsafe to mix them together but I thought it was OK to shock with bleach and use the trichlor in our chlorinator simultaneously.
3. I should just stick with the bleach until the CYA is lowered. This means a more regular checkup of the pool to maintain a proper chlorine level.

Thanks for all your input.

Mike

 

[Guest]

Three things I am taking away from your response:

1. Trichlor sticks are the only thing I can use in our chlorinator; for now not an option.
Correct
2. I should not mix the different forms of chlorine at any time. Do not use trichlor and bleach in any combination. I was not aware of this. I knew it was unsafe to mix them together but I thought it was OK to shock with bleach and use the trichlor in our chlorinator simultaneously.
It is ok to use them in the pool concurrently but you don't want to mix them together in concentrated form and you NEVER want to put anything besides trichlor into a feeder or floater.
3. I should just stick with the bleach until the CYA is lowered. This means a more regular checkup of the pool to maintain a proper chlorine level.
Correct
Thanks for all your input.

Mike

And I would not consider the Clorox toilet tablets in your pool at all. Don't know what is in the Clorox ones but the toilet cleaning tablets I have seen either trichlor or organic bromine (which will convert your pool to a bromine pool!) Remember, many different products that are NOT sodium hypochorite (liquid chlorine bleach) also have the Clorox brand name.

 

[mikeinoleypa01]

Thanks Waterbear!

 

[mikeinoleypa01]

After draining the pool and no longer using any of the trichlor products our CYA level has stabilized. I have been adding, every 3-5 days, one large jug of standard chlorine bleach and the pool looks great (have not used anything for algae this year)!!! I have had to add acid every 2-2.5 weeks to slightly lower the PH level (assuming that the other ingredients in the bleach have some basic elements and have caused this to increase from time to time.) Thanks to all of you for helping us through this. We have learned a lot and are in great shape at the end of the season.

Which leads me to my next question. What do you recommend we do to winterize the pool this year. In the past, we have used the following for our pool (25,500 gallon inground concrete):

o Bioguard or Guardex Burnout formula powdered chlorine - 2 to 4 packs based on what dosage is recommended for our pool size.
o 1 quart of algaecide
o 3 quarts of stain and scale

We plain on closing the pool the week of September 22 2008 and will not open it until end of April 2009 or early May 2009.

Thanks for all your help.

Mike

 

[frustratedpoolmom]

After draining the pool and no longer using any of the trichlor products our CYA level has stabilized. I have been adding, every 3-5 days, one large jug of standard chlorine bleach and the pool looks great (have not used anything for algae this year)!!! I have had to add acid every 2-2.5 weeks to slightly lower the PH level (assuming that the other ingredients in the bleach have some basic elements and have caused this to increase from time to time.) Thanks to all of you for helping us through this. We have learned a lot and are in great shape at the end of the season.

Which leads me to my next question. What do you recommend we do to winterize the pool this year. In the past, we have used the following for our pool (25,500 gallon inground concrete):

o Bioguard or Guardex Burnout formula powdered chlorine - 2 to 4 packs based on what dosage is recommended for our pool size.
o 1 quart of algaecide
o 3 quarts of stain and scale

We plain on closing the pool the week of September 22 2008 and will not open it until end of April 2009 or early May 2009.

Thanks for all your help.

Mike

Glad to hear all is going so well for you!

There are a few reasons why PH rises, but it's not usually caused by bleach in normal daily amounts....how old is your pool? Is your TA still 120?

As for closing, make sure your water is balanced to the recommended levels and then you can just bring your pool up to shock level using bleach, and if you choose add a qt of PolyQuat 60 for algaecide backup/insurance...let it circulate a few hours and then continue with your normal closing procedures... I'm not sure why the stain/scale would be necessary, was this all part of a "winterizing kit"? Or are metals in your water?

 

[mikeinoleypa01]

Thanks for your feedback. TA has been in the 120 - 150 range all summer but it is now at 110. PH has been in the 7.5-7.8 range. Our pool is 4 years old. Because of the high minerals in the water in our area I believe the stain and scale was recommended by our pool builder. However, I am not really sure we need it since I really top off the pool with well water. Perhaps someone else has had experience with this type of product and its recommended uses.

 

[frustratedpoolmom]

Thanks for your feedback. TA has been in the 120 - 150 range all summer but it is now at 110. PH has been in the 7.5-7.8 range. Our pool is 4 years old. Because of the high minerals in the water in our area I believe the stain and scale was recommended by our pool builder. However, I am not really sure we need it since I really top off the pool with well water. Perhaps someone else has had experience with this type of product and its recommended uses.

Well, perhaps have your water tested for metals by the pool store and if they are present, put in a maintenance dose of sequesterant? Or in the spring if you open and have stains you could follow the stain removing procedures.