Cya After A Refill

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Hi All! I just finished refilling my pool after having a plaster repair done. Thanks to this FANTASTIC forum I am pretty well versed in my pool and I am confident in getting things and up and running.

What I am not sure about is getting CYA back up. Previously I was fighting high CYA levels (too high) left behind by the previous homeowner and only in the last year was it even at a normal level. This is a salt pool and it has also had issues in the past with high calcium. (always 400+) I am now thankfully down to about 180 after my refill!

But back on topic. My question is first, do I NEED to get the CYA back up right away or can I do this over time with a shock that contains CYA? I shock with bleach, but I do keep granular shock on hand for times that I am too lazy to run out and buy a ton of bleach. I was thinking that I might just shock monthly with a shock that contains CYA until it comes up. If I do this, will I need to run my chlorine higher? I usually keep it at about 3 - 5 ppm. (I try to keep it at 3ppm, but I always seem to have the thing set too high)

Second, if I need to add CYA, what is my cheapest source? Leslies sells a liquid form. The Taylor book from the 2006 kit talks about it in lbs and I suspect there is a granular form.

Finally, how much do I need to add? I am at an unreadable level of CYA (less then the 10 mark on a Taylor 2006 kit) and the pool is 20,000 Gal. I refilled about 15,000 Gal or maybe a bit more and thus need to add CYA to cover about 15,000 Gal. Unfortunately, the local pool store will not even tell me how much CYA to add. (They want to test it themselves and sell me the whole package, sigh) The Taylor book says 1 lb per 5,000 G = 25 ppm CYA. So to bring up my 15,000 Gal up to 50 ppm I should need about 6 lbs of CYA. Is this correct? How does this convert to gallons of liquid CYA?

Also, while on the topic, is there anything else that I should be looking at? 2 hours after a fill I am looking at Chlorine (TC=3.5), PH (7.0), Calcium (180), CYA(zero) and Salt (Currently 600ppm... LOL) Am I missing anything?

Thanks in advance to all the really smart and helpful folks on this forum. You have saved me a TON of money!

[waterbear]

Hi All! I just finished refilling my pool after having a plaster repair done. Thanks to this FANTASTIC forum I am pretty well versed in my pool and I am confident in getting things and up and running.

What I am not sure about is getting CYA back up. Previously I was fighting high CYA levels (too high) left behind by the previous homeowner and only in the last year was it even at a normal level. This is a salt pool and it has also had issues in the past with high calcium. (always 400+) I am now thankfully down to about 180 after my refill!

But back on topic. My question is first, do I NEED to get the CYA back up right away or can I do this over time with a shock that contains CYA? I shock with bleach, but I do keep granular shock on hand for times that I am too lazy to run out and buy a ton of bleach. I was thinking that I might just shock monthly with a shock that contains CYA until it comes up. If I do this, will I need to run my chlorine higher? I usually keep it at about 3 - 5 ppm. (I try to keep it at 3ppm, but I always seem to have the thing set too high)

Second, if I need to add CYA, what is my cheapest source? Leslies sells a liquid form. The Taylor book from the 2006 kit talks about it in lbs and I suspect there is a granular form.

Finally, how much do I need to add? I am at an unreadable level of CYA (less then the 10 mark on a Taylor 2006 kit) and the pool is 20,000 Gal. I refilled about 15,000 Gal or maybe a bit more and thus need to add CYA to cover about 15,000 Gal. Unfortunately, the local pool store will not even tell me how much CYA to add. (They want to test it themselves and sell me the whole package, sigh) The Taylor book says 1 lb per 5,000 G = 25 ppm CYA. So to bring up my 15,000 Gal up to 50 ppm I should need about 6 lbs of CYA. Is this correct? How does this convert to gallons of liquid CYA?

Also, while on the topic, is there anything else that I should be looking at? 2 hours after a fill I am looking at Chlorine (TC=3.5), PH (7.0), Calcium (180), CYA(zero) and Salt (Currently 600ppm... LOL) Am I missing anything?

Thanks in advance to all the really smart and helpful folks on this forum. You have saved me a TON of money!

Since you said that this is a salt pool then you DO need to get the CYA to the recommended level (normally 80 or 100 ppm, depending on the manufacturer of the SWG as soon as you bring the salt water chlorine generator online. What brand/model do you have?)

Cheapest source of CYA is granular CYA. Add it slowly to the skimmer, do not clean or backwash for a week, and test the level a week later. Once the CYA is on target adjust the generator to maintain your FC at 4 or 5 ppm. You should not need to shock with a salt pool normally. You only really need to shock when testing shows combined chloirne above .5 ppm or after heavy use ( say a pool party with 10 kids in the pool)

If your CYA is currently 0 ppm and your pool is really 20k gallon then you need about 13 lbs to get you up to 80 ppm. I would ADD 10 LBS , wait a week test, and see where you are.

Your calcium is low and so is your pH but that should rise on it's own. Did they do an acid startup for the new plaster? How soon before you can add salt. Normally they say a month and if that is the case then chorinate your pool with trichlor in a floater until you can add salt and bring the salt water chlorine generator online. In the meantime the acidic trichlor will help with the acid demand created by new plaster and will add a small amount of cya to the water.

You did not mention where your TA is. Normally you want to keep it at 70 or 80 ppm and then adjust the calcium hardness to maintain saturation index,.

The net effect of lower TA and maximum recommended CYA is better pH stability. The reasons a somewhat complex and I do not have time to go into them now.

[Rhumbline]

Since you said that this is a salt pool then you DO need to get the CYA to the recommended level (normally 80 or 100 ppm, depending on the manufacturer of the SWG as soon as you bring the salt water chlorine generator online. What brand/model do you have?)

Cheapest source of CYA is granular CYA. Add it slowly to the skimmer, do not clean or backwash for a week, and test the level a week later. Once the CYA is on target adjust the generator to maintain your FC at 4 or 5 ppm. You should not need to shock with a salt pool normally. You only really need to shock when testing shows combined chloirne above .5 ppm or after heavy use ( say a pool party with 10 kids in the pool)

If your CYA is currently 0 ppm and your pool is really 20k gallon then you need about 13 lbs to get you up to 80 ppm. I would ADD 10 LBS , wait a week test, and see where you are.

Your calcium is low and so is your pH but that should rise on it's own. Did they do an acid startup for the new plaster? How soon before you can add salt. Normally they say a month and if that is the case then chorinate your pool with trichlor in a floater until you can add salt and bring the salt water chlorine generator online. In the meantime the acidic trichlor will help with the acid demand created by new plaster and will add a small amount of cya to the water.

You did not mention where your TA is. Normally you want to keep it at 70 or 80 ppm and then adjust the calcium hardness to maintain saturation index,.

The net effect of lower TA and maximum recommended CYA is better pH stability. The reasons a somewhat complex and I do not have time to go into them now.

Thanks! I will have to track down some granular CYA.

They did not do an acid startup since it was just a plaster repair. I had a rebar come through the wall and it needed to be cut out and pounded back and repaired. I am trying to get another few years out of my plaster before spending the big bucks.

I was not told with the patch that I should not add salt and I have started doing that... So we shall see. I have not checked TA yet since I know that the first few days with the new salt things will change a good bit on the TA and Ph front. I made sure my PH was not too badly out of whack at startup and I will make sure it all balances out later in the week when I get the chlorine and salt in line. Unfortunately I am also fighting a big mess since while the pool was down we had 2 big storms that dropped everything from branches and leaves to dirt and lawn chairs in the pool. Thus I am still trying to vacuum up all the small crap that is down there while I am dealing with chemicals. (oh, and the rest of my life. lol)

Thanks for all your help.

[waterbear]

Thanks! I will have to track down some granular CYA.

I have not checked TA yet since I know that the first few days with the new salt things will change a good bit on the TA and Ph front.

Where did you ever get an idea like that? You should have your TA, CH and pH inline BEFORE doing anything else (except perhaps adding some chlorine to keep algae at bay.)

I made sure my PH was not too badly out of whack at startup and I will make sure it all balances out later in the week when I get the chlorine and salt in line. Unfortunately I am also fighting a big mess since while the pool was down we had 2 big storms that dropped everything from branches and leaves to dirt and lawn chairs in the pool. Thus I am still trying to vacuum up all the small crap that is down there while I am dealing with chemicals. (oh, and the rest of my life. lol)

Thanks for all your help.

Step by step:

Get the pool clean first!

Add some chlorine (for now I would get a floater and put some trichlor in it, don't worry abut CYA, a few tabs won't add that much and you are going to need a lot of CYA anyway! Keep the floater in your pool to keep it chlorinated until the SWCG is online and don't put it online until the CYA is at target!)

Next adjust your TA either up (easy, just add baking soda) or down (more work but necessary!) to around 70-80 ppm (the link is in the spa water chemistry section but the method is the same, lower the pH to 7.0 using an acid demand test if you have one, test TA, aerate the water to outgas CO2 and bring the pH back up without affecting TA until the pH tests above 7.4. Repeat until TA lowers to desired target. Depending on how high it is when you start this could take a LOT of acid and take some time. The better you can aerate to raise pH the faster this process goes. A floating fountain that attaches to a return is a good way to aerate as are water features like waterfalls and deck jets. Also, if you have a spillover spa attached to the pool you have a great aerator built in. Just put it in spillover mode and open all the spa jets and aerators and bubblers!)

IF you pH is high at this point add a bit of acid to lower it. shoot for around 7.6 and not lower since the lower the pH the FASTER it rises. (not going into the technical reasons right now because of time constraints). Your pH might be high if you needed to raise it.

IF your pH is low DO NOT ADD ANY CHEMICALS. Just aerate the water until it rises above 7.4 and stop. IF your pH is low it is because you lowered the TA and did not finish the process. Just aerate until the pH rises. You pH should not be below 7.0 if you did the TA lowering procedure properly!

Next adjust your CH to about 400 to 450 ppm (yes you read that right--It should get your saturation index in line if you follow this advise)

Add your salt and CYA next but do not take out the floater until you have the max CYA reading recommened by your SWCG manufactuer. (From other posts you have made I believe you might have a Jandy Aqaupure so your salt should be 3000-3500 ppm and your CYA SHOULD BE 75 PPM! You want it at the max! If you have a different SWCG either post the mode and make or look in your manual for the recommended salt level and the MAXIMUM CYA. You want the CYA at Maximum recommended level. It will add to pH stability since the cell can be set to a lowr output to maintain the desired FC and that means less outgassing of CO2 from hydrogen bubble generation in the cell.)

To recap, TA at the minimum or even a bit below...70-80 ppm

CH to 400 or so to get saturation index in balance

pH to 7.6...when pH rises add acid when it climbs to or above 7.8 but do not lower below 7.6 for the best pH stability

Finally, adding borates(either by borax and acid or by using boric acid or a commercial product like Proteam Supreme or Bioguard Optimizer or Poollife Endure) to 50 ppm will also help with ph stability and lessen the frequency of acid additions when all the above are followed. Use LaMotte borate test strips to test borates. They are the easiest to read and provide more than enough precision for borates in a pool.

to help you calculate how much you need to add you might want to take a look at Jason's Pool Calculator.