High CYA and Calcium Hardness

[TXTyphoon]

The pool:
16000 gallons
plaster
in-ground
6 years old
Has a UV/Clear03 system
located in north Texas

The Problem:
Pool has been "trouble-free", really I think its just been hiding its secret, up until last season when we starting having persistent issues with algae. Unfortunately we didn't think much of it and just kept shocking and adding more trichlor tabs and adding more algicide. After facing the same issues this year I finally admitted we had a real issue. Of course, what did we do, well we went to the pool store and you all know what they did. They sold us more stuff. Being fed up with the issues I finally took the time to do some research and boy do I wish I had done that years ago.

What we have done:
1. We bought a Taylor k-2005 and a K-1106 test kit and started testing regularly.
2. We reduced our Phosphates to 0 with 2 treatments of PhosFree. (I already had it and it worked)
3. We tried a 8oz treatment of Bia-Active to try to reduce CYA
4. Replaced the Paramount UV system with a Del UV-C 50 because the Paramount was leaking. Added a new bulb to the O3 system as it burned out. In hind-sight, I think I should have just plumbed both systems out of the mix and saved the money.

Today's measurements:
FC - near 0
TC - near 0
CYA - 400 (In order to be on the scale I had to dilute 10ml pool water with 30ml tap water to get a reading around 100)
PH - 7.6
TA - 130 (measured)
CH - 650
Pho - 0

Last pool store test for comparison:
PH - 7.8
TA - 75
CYA - 206
FC - .3
TC - .3
CH - 477
TDS - 500
Pho - 0
CU - .3
FE - 0

The problem:
We are still fighting algae and I can't keep any chlorine in the pool. I'm adding a gallon of 10% liquid a day and the FC is always near 0 by the end of the day. We also need to address the high CYA and CH levels. I'm also a bit confused by the TA level, if I adjust that from what I've read based on my CYA level its near 0.

I think it is inevitable that we have to drain at least half the pool. I was hoping to avoid that due to water conservation/cost concerns but with the high CH level I don't think there is any way around that. That would also help resolve the CYA problem to some extent. The question is how much to drain? Half? We are actually expecting some good rain over the next few days and I'm wondering if I should use that to help replenish the water. Am I on the right track here, other options?

Thanks,

Brian

 

[Griswald]

If you really have a 400 CYA level, you need to swap around 90% of your water. It should be closer to 40.

 

[ajw22]

How do you intend to chlorinate the pool once you get the CYA done?

No reason to adjust other chemicals until you drain and lower CYA.

You need to get your CYA down around 60. That requires close to a 90% drain. Rain is not going to help you get there.

What is the pH, TA, CH of the fill water you will use?

We have a No Drain Water Exchange process you can read about in Draining - Further Reading

 

[Jimrahbe]

Brian,

You can only fix your problem by draining your pool and starting over.

Sorry, but the idea that you can buy a magic potion at the pool store that will drastically reduce your CYA is just a load of Bull Feathers. It is just not true, no matter what they promise. You need to get your CYA down to 50 or less.

If you have looked at our site at all you already know that we do not recommend UV or Ozone systems as they just don't work. The problem is you just don't know as you have no real way to test them. This is why this site is dedicated to teaching homeowners how to maintain their pools using chlorine as the only sanitizer.

Because your CYA is so high, it makes sense to just start over. If you let the city know you need to fill your pool the cost will not be as much as you might think. I'm sure the cost has gone up some, but a few years ago it was about $50 bucks for my 17K pool.

We would be glad to get you pointed in the right direction if you wish,

Thanks,

Jim R.

 

[tim5055]

The Problem:
Pool has been "trouble-free", really I think its just been hiding its secret, up until last season when we starting having persistent issues with algae. Unfortunately we didn't think much of it and just kept shocking and adding more trichlor tabs and adding more algicide. After facing the same issues this year I finally admitted we had a real issue. Of course, what did we do, well we went to the pool store and you all know what they did. They sold us more stuff. Being fed up with the issues I finally took the time to do some research and boy do I wish I had done that years ago.

What we have done:
1. We bought a Taylor k-2005 and a K-1106 test kit and started testing regularly.
2. We reduced our Phosphates to 0 with 2 treatments of PhosFree. (I already had it and it worked)
3. We tried a 8oz treatment of Bia-Active to try to reduce CYA
4. Replaced the Paramount UV system with a Del UV-C 50 because the Paramount was leaking. Added a new bulb to the O3 system as it burned out. In hind-sight, I think I should have just plumbed both systems out of the mix and saved the money.

The problem:
We are still fighting algae and I can't keep any chlorine in the pool. I'm adding a gallon of 10% liquid a day and the FC is always near 0 by the end of the day. We also need to address the high CYA and CH levels. I'm also a bit confused by the TA level, if I adjust that from what I've read based on my CYA level its near 0.

I think it is inevitable that we have to drain at least half the pool. I was hoping to avoid that due to water conservation/cost concerns but with the high CH level I don't think there is any way around that. That would also help resolve the CYA problem to some extent. The question is how much to drain? Half? We are actually expecting some good rain over the next few days and I'm wondering if I should use that to help replenish the water. Am I on the right track here, other options?

Well, welcome ot TFP!!

You have the right idea, but you really need to replace about 80 - 90% of the water to get the CYA under control.

Ignore the pool store numbers, as you can see they are not close on the CYA. Trust your testing.

We generally ignore Phosphates because as you can see, when it's "0" you can still have algae.

You have proven what we say, Bio-Active is not the magic potion some swear it is.

You are right, you should have just plumbed both systems (UV/O3) out of the mix and saved the money.

The Trichlor and shock kept adding to your CYA issues.

Something to know, algecide is really more of a preventative. It doesn't really get rid of algae once you have it. It is what is adding the copper to your water, so you may want to stop it now.

Your K-2005 is a good kit, but you really need the FAS/DPD chlorine test. The color match test in the 2005 is not specific enough and it doesn't go high enough. This is the test you want.

FAS/DPD Chlorine Test Kit

tftestkits.net

For now -

• Stay away from the pool store
• Keep adding the liquid chlorine until you get your FAS/DPD test and can do a water exchange.
• Do some reading in Pool School have you read?

Start with these:

ABCs of Water Chemistry


Recommended Pool Chemicals


How to Chlorinate Your Pool

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

So, welcome to TFP!!

 

[TXTyphoon]

Appreciate the replies, going to try to provide answers to questions/comments here.

How do you intend to chlorinate the pool once you get the CYA done?
Liquid Chlorine only moving forward.

What is the pH, TA, CH of the fill water you will use?
TA - 70
CH - 125
PH - 8

FAS/DPD test kit ordered.

I looked up our water rates on the city's site and it looks like it is $5.77 per 1000g so a full fill will be about $93.00. They have a tiered system with rate changes every 15000 gallons. I'll probably wait until our next billing cycle and just bite the bullet while reducing our lawn watering. Any issue using the current pool water on the lawn?

Given the pool type and location should I be concerned about fully draining the pool? We haven't had any real rain in months, though we are expecting 2-8 inches over the next couple of days. I'm leaning towards a 50% drain and then using the no-drain exchange method mentioned above to complete a 90% replacement. Thoughts on that approach? Anything else we should do while it is drained? Scrub it good with?

Thanks,

Brian

 

[Jimrahbe]

Brian,

If you contact the city before filling the pool, they may have a program where they do not charge you for the sewer portion of you water bill.

Thanks,

Jim R.

 

[ajw22]

I'm leaning towards a 50% drain and then using the no-drain exchange method mentioned above to complete a 90% replacement. Thoughts on that approach? Anything else we should do while it is drained? Scrub it good with?

I would do one method or the other.

If you are trying to use less water mixing the two methods will use more water then either alone.

If you are going to do the No Drain methods then get it setup and do it all that way.

 

[TXTyphoon]

Brian,

If you contact the city before filling the pool, they may have a program where they do not charge you for the sewer portion of you water bill.

Thanks,

Jim R.

I looked into this, it is clearly defined in the fee schedule so it isn't an issue. They look at the average water use over three months, November, January, and February and set the sewer rate for the year. As long as we fill outside those there months we won't see a hit for sewer. It isn't a 1:1 usage/sewer rate each month.

 

[TXTyphoon]

I would do one method or the other.

If you are trying to use less water mixing the two methods will use more water then either alone.

If you are going to do the No Drain methods then get it setup and do it all that way.

I'd prefer to just drain and fill. I think that can be done pretty quickly given the relative small size of the pool and would like to use as little water as needed overall.

 

[Jimrahbe]

Brian,

Don't use your pool pump to drain the water. Rent or buy sump pump.

Most gunite pools are not going to pop out of the ground if you remove the water for a day or two.

If you can dig a post hole in your yard about 3 feet deep and it fills with ground water, then that would be a problem or you live right next to a lake, or know you have a very high-water level, then it could be an issue.

Keep in mind that they plaster thousands of pools a year without any issues.

Thanks,

Jim R.

 

[pjt]

How do you intend to chlorinate the pool once you get the CYA done?
Liquid Chlorine only moving forward.

You would be a good candidate for a SWG.

 

[TXTyphoon]

You would be a good candidate for a SWG.

Yeah, in hindsight, probably should have done that when we built the pool. Might be something we consider once we have this thing back under our control. However, it would be a new variable in the equation at the moment.

 

[TXTyphoon]

Brian,

Don't use your pool pump to drain the water. Rent or buy sump pump.

Most gunite pools are not going to pop out of the ground if you remove the water for a day or two.

If you can dig a post hole in your yard about 3 feet deep and it fills with ground water, then that would be a problem or you live right next to a lake, or know you have a very high-water level, then it could be an issue.

Keep in mind that they plaster thousands of pools a year without any issues.

Thanks,

Jim R.

That's what I was thinking too, thanks for confirming. Digging a 3' deep post hole in this ground isn't easy, there sure wasn't any water in it the last time I did it.

 

[JJ_Tex]

I didnt catch where in TX you are, but if you are in the Dallas area we are supposed to get a ton of rain over the next day or two. Today would be an ideal day to do it, maybe the rain will help fill it back in.

If you do it after the rains, I would give it some time to dry up and lessen your chances of popping out of the ground.

 

[TXTyphoon]

I didnt catch where in TX you are, but if you are in the Dallas area we are supposed to get a ton of rain over the next day or two. Today would be an ideal day to do it, maybe the rain will help fill it back in.

If you do it after the rains, I would give it some time to dry up and lessen your chances of popping out of the ground.

We are in the NE DFW area and it has been raining since last night. South of here has received over 9 inches of rain since last night. I've had the pool on high all day trying to mix in as much rainwater as possible just to see what, if anything, changes. However, the plan is to fully drain the pool in the next couple of weeks and start over once things have dried out a bit.

 

[TXTyphoon]

Pool draining has commenced. Appreciate all the input on this thread. I’ll post test updates post fill. Going to give it a quick power wash post drain. I’ve been told that given the high level of CYA the plaster may hold some and to hold off adding any conditioner until things settle. Thinking real hard about adding a SWCG too. Any recommendations for a pool this size? All other equipment is Pentair.

Brian

 

[JJ_Tex]

Pool draining has commenced. Appreciate all the input on this thread. I’ll post test updates post fill. Going to give it a quick power wash post drain. I’ve been told that given the high level of CYA the plaster may hold some and to hold off adding any conditioner until things settle. Thinking real hard about adding a SWCG too. Any recommendations for a pool this size? All other equipment is Pentair.

Brian

Good luck. I would not power wash your plaster though. That is an old wives tale that CYA attaches to the plaster, and I would be worried about shortening the life of my plaster and/or leaving power-washing marks on the walls.

Also, if you switch to a SWCG a Pentair IC40 would be perfect.

 

[TXTyphoon]

Operation complete. Pool has been drained, cleaned and filled. Here are the initial readings.


Off to get some more bleach and some conditioner. I’m going to ease into the CYA target over a few days. Cloudy and overcast the next few days.

Brian