Questions on pH, FC, TA, and CYA results

[KimBee]

Then you must have added alot of calcium or been using a lot of cal hypo. There is no way your CH is that high from fill water.

I just did the CH test using water right from the spigot that was used to fill the pool and it‘s only 175 ppm!

Unfortunately I don’t have a log of what’s been added to the pool other than what I’ve done starting this weekend. We’ve been paying a pool guy to manage the chemicals up to this point.

So now that I corrected the pH and TA, the CH is high and there is zero CYA. What do I do next?

 

[KimBee]

The sample may turn purple during the test, or go to blue for a moment and then turn back to red/pink. This is called a “fading endpoint” and is caused by interference from metal ions. If this happens, do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total.

Also I did do this modified method with the pool water and that’s how I got 27 drops total for a true blue = 675 ppm

 

[Texas Splash]

Now that you have a much better CH reading, the key going forward is to manage the pH by ensuring it doesn't get to high. Always keep it from exceeding 7.8 to avoid scale.

Over time as you use acid to control the pH, you might find the TA getting a bit low. When the TA hits 50, consider adding a little baking soda. Only about 10 ppm with though.

 

[mknauss]

I cannot believe they could have added enough cal hypo to increase the CH that much. And if they added calcium, they were true idiots.

You can manage it with that level of CH. It will be a challenge as your SWCG will want to scale up.

Easiest is to drain the pool and start over. But that is up to you.

 

[Texas Splash]

Now that you have a good understand of how the CH, pH, and TA work together, it's time for algae prevention.

Now you can add that 60 ppm of conditioner. Add liquid chlorine as needed to keep the FC around 5 ppm until your SWG can maintain that range as noted on the FC/CYA Levels.

Tomorrow or the next day, retest the CYA to see if you were accurate to make 60. You can always add more if needed, but you can't remove it without changing water.

 

[KimBee]

I cannot believe they could have added enough cal hypo to increase the CH that much. And if they added calcium, they were true idiots.

You can manage it with that level of CH. It will be a challenge as your SWCG will want to scale up.

Easiest is to drain the pool and start over. But that is up to you.

Yeah, completely draining the pool would be our last choice…but what are your thoughts on doing a displacement by adding hose water to the pool and the excess volume will just exit via the overflow drain?

And is this urgent? Or can I move on to the CYA?

 

[KimBee]

Now that you have a good understand of how the CH, pH, and TA work together, it's time for algae prevention.

Now you can add that 60 ppm of conditioner. Add liquid chlorine as needed to keep the FC around 5 ppm until your SWG can maintain that range as noted on the FC/CYA Levels.

Tomorrow or the next day, retest the CYA to see if you were accurate to make 60. You can always add more if needed, but you can't remove it without changing water.

just double checking that I can indeed proceed with adding the stabilizer with pool CH at 675?

 

[mknauss]

And is this urgent? Or can I move on to the CYA?

If you add CYA, plan to live with the water you have until this winter.

Like I said, you can manage a CH of that level. You need to become very conversant in CSI. You must manage your water chemistry to keep CSI negative. It can be done, I have done it. But you must plan to be adding acid every other day or so from now until October.

 

[KimBee]

If you add CYA, plan to live with the water you have until this winter.

Like I said, you can manage a CH of that level. You need to become very conversant in CSI. You must manage your water chemistry to keep CSI negative. It can be done, I have done it. But you must plan to be adding acid every other day or so from now until October.

Wow, okay. What level CH would I need to get the pool to in order to not need that level of routine acid adding? Would doing a continuous water displacement with the hose help enough to make an impact?

 

[Texas Splash]

As Marty said, you have to stay on top of that pH. Many people do it, so can you. Test your pH every couple days to be sure.

 

[mknauss]

What level CH would I need to get the pool to in order to not need that level of routine acid adding? Would doing a continuous water displacement with the hose help enough to make an impact?

At 350 ppm CH, it is much easier. You still will have to add acid once a week or so.

You will need to drain from the bottom and add to the top. I assume you have salt in the water and with the CH your pool water is more dense than your fill water.

 

[IceShadow]

Options as outlined are:

- No-drain water exchange about half the pool water or so to bring it down to 350CH or so, which will be easier to avoid scale. Then add the CYA to bring to target.

- Live with the higher CH, carefully manage CSI, and start with CYA and FC now.

 

[mknauss]

Would need to exchange about 3/4 of the pool volume to get close to 350 ppm CH.

 

[IceShadow]

Would need to exchange about 3/4 of the pool volume to get close to 350 ppm CH.

Oh right, because of the CH in the fill water.

 

[KimBee]

Ok got it - thank you all!

 

[mknauss]

Another option -- you can add borates and it will help you manage the CH level and keep the SWCG free from scale. Will reduce how often you have to add acid. Hopefully down to once a week or so.

Borates in pool - Further Reading

www.troublefreepool.com

 

[Texas Splash]

KB, a lot of info has been thrown at you in less than 48 hrs. You must feel a bit overwhelmed. You made it through yesterday's pH/TA crisis quite well. The CH issue, while important, is not an emergency like the other was, so think it through. We do this all the time, so the options being laid-out seem second-nature to us, but perhaps not you. It's also important that you continue to get comfortable with all the testing as we've learned a few tings about that as well.

Whether you decide to exchange water or not, we'll coach you through it when you're ready. Until then, remember the following:

** Algae control is all about the FC-to-CYA ration as noted on the FC/CYA Levels.
--- Whether you change water or not, keep the FC strong to avoid algae.
** Scale control is all about the combination of water temp, CH, TA, and pH.
--- Until you decide, keep the pH from exceeding 7.8, ideally more around 7.5 since your CH is elevated.

We'll be around if you have any questions.

 

[KimBee]

Just to close the loop with all of you wonderful advisors on here, on Sunday evening I ended up changing out about 1/3 of the pool water using my sump pump at the bottom of the deep end and hose at the top of the shallow end. That brought down the CH somewhat to a range I think I can live within. And it took the Salt down a bit, too (my salt strip’s max is 5000, so I bet the Salt before the exchange was actually much higher than I even realized).

Numbers tonight (also in pic):
FC 9.5 (with no one home the automatic cover was on all day so dialed down the salt cell tonight with this result)
pH 7.8 (holding steady at 7.8 since yesterday despite adding the volume of MA the app told me to )
TA 60
CH 425
CYA 30 (After the water exchange I added 1 gallon of liquid stabilizer late Sunday night and this has been holding at 30 since Monday evening)

I feel like things are in a MUCH better place than just a few days ago and I learned so much in the process. Thank you for all the support - I think I’m starting to get the hang of this.

 

[Texas Splash]

You made some great progress. Now that the water exchange is done, don't forget you'll want to determine if that CYA needs to get bumped back up to the TFP recommended level of about 70. You do have a cover, so that might allow you to operate with a slightly less CYA. You might start at 50 and go from there if the FC doesn't hold well. Just something to keep in mind.

 

[mknauss]

Do you have a water softener? Using softened water for fill water whenever possible will slow the CH rise.