Calcium hardness and salt rising, pH question

[mprzybylski]

Hey everyone,
My pool was open in Arizona almost a year ago to the day (August 2 will be official) and my details are all in my signature. I have a few questions now that I've settled into a routine and a bit of a troubling trend.

My logs are here

Question 1
My CH has risen steadily over the past six months to a level now that I'm above the acceptable limits. It has increased from 475 to (at today's measure) 800. According to Pool Math, I know that I have to drain the pool (roughly 46% of it) and refill to get it back to within the target CH of 450. Is it ok if I put this off until this winter or do I need to get on it immediately? It's hot here (110s on the regular now) and I'm a bit worried about draining and something happening to my plaster which isn't even a year old, not to mention that we can't swim during this time and with this weather thats a tough proposition. I know it'll probably only take a day or two to do this, but just wanted to see if this is something I can put off until the winter or is it something I need to get done right away to prevent any damage to the pool? Additionally, if I CAN put it off, I'm assuming its safe to swim until then? My reservation with putting it off is that it's been rising by a lot month over month so I want to make sure I don't do any long term damage.

Question 2
My salt level has also steadily risen over that time, though not as much as the CH. I'm now at 4,200 according to today's test. I suppose I can kill two birds with one stone by draining, but if the answer to the above is that yes, I can put it off til winter, does that also apply for the salt and not cause any long term damage?

Question 3
I'm maintaining my pH relatively well and I test usually every Saturday and Wednesday each week during the summer (and just did on Saturdays during the winter). My pH almost always is above 7.8 when I test (usually in the 8-8.2 range) so I'm dumping roughly 36-48 oz of muriatic acid every time after I test. I know from reading this site that sometimes pH can take over a year or more to completely settle in so you don't have to dump that much MA every few days, but I just wanted to confirm this is normal and expected and that I'm not doing anything wrong here.

Thanks for any help offered.

 

[Texas Splash]

Is it ok if I put this off until this winter

Put it off and wait. Definitely.

but if the answer to the above is that yes, I can put it off til winter, does that also apply for the salt and not cause any long term damage?

Correct, wait. As long as your cell isn't shutting down you are fine.

I just wanted to confirm this is normal and expected and that I'm not doing anything wrong here.

PH is perfectly normal. Just stick with it. It may be difficult and a bit more work, but if you can keep the pH even lower, say 7.5-ish, it will help to compensate for the elevated CH level. You can also allow the TA to fall to about 50 before having bump it back up a little.

Hope that helps.

 

[mprzybylski]

@Texas Splash Good to know thank you. So I'm not going to cause any more issues by waiting and the CH rising steadily until the winter? Is there a way for me to slow the rise of CH until then?

 

[mknauss]

Is there a way for me to slow the rise of CH until then?

Do you have a whole house water softener? If so, you need to use soft water for fill water.

 

[duraleigh]

i think you have a potential issue. Measure the pH and TA of your fill. Then measure the CYA and TA of your pool. Post that up.

 

[mprzybylski]

Do you have a whole house water softener? If so, you need to use soft water for fill water.

I do but my hose bibs do not run through it.

 

[mprzybylski]

i think you have a potential issue. Measure the pH and TA of your fill. Then measure the CYA and TA of your pool. Post that up.

I will do that in the morning and post it up, thank you. What makes you say that I have a potential issue, I'm curious?

 

[proavia]

Ideally, you should find a way to plumb the water softener to your autofill. Any chance of plumbing soft water from the softener thru the outside garage wall?

Your un-softened hose bib and autofill has a CH close to 225 or higher with a TA around 120-130.

In the East Valley your entire pool will evaporate at least one time - possibly 1.5 times - in one year. So at a minimum, your CH will rise by your un-softened CH yearly.

In the fall, do a complete drain/refill. Refill with unsoftened water.
If you are going to continue using hard water for the autofill, do NOT adjust the CH upward - it will rise quick enough on its own. If using softened water with the autofill, shoot for the low end of the CH range.

When dosing salt after the drain/refill, shoot for the lower end of the salt range too.

 

[mprzybylski]

i think you have a potential issue. Measure the pH and TA of your fill. Then measure the CYA and TA of your pool. Post that up.

Tested my fill water.

pH: 7.6-7.8 (somewhere in that range as far as I can tell)
TA: 100
CH: ~225 (I always have a hard time telling exactly when it turns from purplish/blue to true blue but its between 200-250)

@proavia Thank you SO much for that explanation, that makes complete sense. For some reason I never considered and totally forgot about my autofill being connected to the hose bib which absolutely makes sense as to why this is happening.

I have a neighbor who actually runs a water company and he is going to come by later today to give me a quote on installing a third hose bib that is softened. I'm lucky in the sense that my pool equipment is on the garage side and the other side of the wall has the softener so installing a third bib that is softened will not be a huge issue and i can then use that to connect the auto fill and subsequently to fill my pool with. Do you think this is going to be a good solution to this issue? Or is draining and re-filling on a yearly basis par for the course and something I should just expect moving forward?

 

[duraleigh]

pH: 7.6-7.8 (somewhere in that range as far as I can tell)
TA: 100
CH: ~225

That's pretty decent fill water and indicates you can get some longer term relief from your current conditions.

That said you have good potential in your pool for calcium precipitation (scaling) because:

1. Your CH is wa-a-ay to high (450 is the highest part of the TFP range)
2. You are keeping your pH too high. In your case, I would suggest 7.2
3. Arid AZ is high evaporation territory indicating (you are right) your problems will ONLY continue to increase.

If it was my pool, I would immediately start a water exchange. You simply set up a hose to siphon water from your pool near the top 1' of depth. Next you match that drain rate with incoming (colder) fill water from your spigot, It works surprisingly well and you never uncover your plaster.

You can continue this until you get a roughly 50% exchange and EVERYTHING (pH, salt, TA and CH) will be better

Calcium Scale is quite problematic and you don't want it. Don't wait 'til Fall.

And, yes, a water softened pool refill spigot solves your entire problem permanently

 

[proavia]

Not much of a density difference in the water at our present desert water temps (maybe less than a 5 degree difference). The tap water temp is probably about mid 80's and the pool is probably 90-92. Here in AZ, we are "lucky" to have the water main from the meter at the street to the house buried 12" below ground level and the tap water heats up quickly. And given our outside temp of mid 80's for a low and 105-110 for a high, the temperature inside the garage is usually in the low 100's during the day. With the water softener tank in the garage, the refill/autofill softened water will be warm too. Even using un-softened water from the present hose bib will yield a water temp of mid 80's.

While not ideal - with careful monitoring of pH and TA, the CH can be managed up to ~1000 or so. It will take daily or every other day pH testing/dosing and monitoring TA at least weekly. The pH is going to need to be maintained around 7.2 - put all the numbers in PoolMath, then change the pH to 7.2 in PoolMath to see how CSI is affected.

A 50% water exchange with a starting CH of 800 and a refill CH of 225 will yield a finished CH of ~500+. Surely better than 800, but will still require a further drain in the fall to get it down to the lower end of the recommended range. A water exchange with softened water would be nice, but many softeners will run out of softened water after 2000-3000 gallons or less - and then require an hour or so to regenerate. Using unsoftened tap water for an exchange is a better option than using softened water, given a 50% exchange in a 15k pool.

With staying on top of the pH, TA and CSI, @mprzybylski can possibly hold off on a water exchange or full drain/refill until fall. Doing a full drain/refill will be quicker, more efficient and possibly save some water. If Gilbert has water rates close to Chandler, it will cost less than $50 for the refill water on the monthly bill.

If a full drain is done in the fall, refill is done with unsoftened water. Then continue to use unsoftened water for the autofill until reaching the lower end of the recommended range for CH. Then switch to softened water for the autofill. Shooting for the low end of the CH range will provide a cushion in case the water softener runs out of soft water and needs a regeneration cycle when the autofill calls for additional water.

Maybe @JoyfulNoise (who lives about an hour south of here) will chime in with his experience with high CH water and how he managed his pool with CH over 800 a few years ago. And how using softened water is working out now.

No matter if you decide to use the exchange method or a full drain/refill, check with the city of Gilbert to see where they require you pump the waste water if it cannot be fully maintained on your lot..

I started using softened water for the autofill about one year ago. My CH has risen 50 ppm in that one year. Prior to using softened water for the autofill, my CH would rise 300-400 ppm per year.

 

[mgtfp]

Not much to add regarding CH, you are already getting great advice there.

Just wanted to address your question regarding your rising salt levels. With an SWG that shouldn't happen unless salt is being added.

So, a few questions:

How are you testing your salt level?

Have you been adding anything that would increase the salt level? Salt, Calcium-increaser or additional chlorine?

Does your fill water contain significant amounts of salt?

 

[mprzybylski]

Not much to add regarding CH, you are already getting great advice there.

Just wanted to address your question regarding your rising salt levels. With an SWG that shouldn't happen unless salt is being added.

So, a few questions:

How are you testing your salt level?

Have you been adding anything that would increase the salt level? Salt, Calcium-increaser or additional chlorine?

Does your fill water contain significant amounts of salt?

I'm testing the salt using the K-1766 salt kit. The only things I'm adding is basically what PoolMath tells me to, mostly muriatic acid. Since opening the pool, I have not really added anything other than what was necessary for startup and then just following pool math. Over the winter I added maybe a gallon of liquid chlorine when it was too cold for the SWG to be running and I had to get chlorine back to within tolerances, but otherwise nothing else. I haven't tested the salt level of the fill water recently but when the pool was filled last year with that same water the salt level was non-existent and I had to pour in four large bags of salt to get it to within the appropriate level (over time of course).

 

[mprzybylski]

Not much of a density difference in the water at our present desert water temps (maybe less than a 5 degree difference). The tap water temp is probably about mid 80's and the pool is probably 90-92. Here in AZ, we are "lucky" to have the water main from the meter at the street to the house buried 12" below ground level and the tap water heats up quickly. And given our outside temp of mid 80's for a low and 105-110 for a high, the temperature inside the garage is usually in the low 100's during the day. With the water softener tank in the garage, the refill/autofill softened water will be warm too. Even using un-softened water from the present hose bib will yield a water temp of mid 80's.

While not ideal - with careful monitoring of pH and TA, the CH can be managed up to ~1000 or so. It will take daily or every other day pH testing/dosing and monitoring TA at least weekly. The pH is going to need to be maintained around 7.2 - put all the numbers in PoolMath, then change the pH to 7.2 in PoolMath to see how CSI is affected.

A 50% water exchange with a starting CH of 800 and a refill CH of 225 will yield a finished CH of ~500+. Surely better than 800, but will still require a further drain in the fall to get it down to the lower end of the recommended range. A water exchange with softened water would be nice, but many softeners will run out of softened water after 2000-3000 gallons or less - and then require an hour or so to regenerate. Using unsoftened tap water for an exchange is a better option than using softened water, given a 50% exchange in a 15k pool.

With staying on top of the pH, TA and CSI, @mprzybylski can possibly hold off on a water exchange or full drain/refill until fall. Doing a full drain/refill will be quicker, more efficient and possibly save some water. If Gilbert has water rates close to Chandler, it will cost less than $50 for the refill water on the monthly bill.

If a full drain is done in the fall, refill is done with unsoftened water. Then continue to use unsoftened water for the autofill until reaching the lower end of the recommended range for CH. Then switch to softened water for the autofill. Shooting for the low end of the CH range will provide a cushion in case the water softener runs out of soft water and needs a regeneration cycle when the autofill calls for additional water.

Maybe @JoyfulNoise (who lives about an hour south of here) will chime in with his experience with high CH water and how he managed his pool with CH over 800 a few years ago. And how using softened water is working out now.

No matter if you decide to use the exchange method or a full drain/refill, check with the city of Gilbert to see where they require you pump the waste water if it cannot be fully maintained on your lot..

I started using softened water for the autofill about one year ago. My CH has risen 50 ppm in that one year. Prior to using softened water for the autofill, my CH would rise 300-400 ppm per year.

Thank you, this all makes sense, really appreciate the very detailed responses you've provided here and its great to see how someone close by has managed this in the past.

 

[mprzybylski]

You simply set up a hose to siphon water from your pool near the top 1' of depth.

Can you elaborate on how you do this? I'm assuming its not as simple as just dropping the end of the hose into the pool and the other end into wherever you want to drain because how would the water be "pushed" to go through the hose?

 

[duraleigh]

You create a siphon. Google it. Post back if you need more info

 

[mprzybylski]

You create a siphon. Google it. Post back if you need more info

Interesting, learn something new every day. Thanks!

 

[Nikilyn]

I live in the same neighborhood as the OP and am having the same problems. I actually have some scale already on some tiles and the waterfall . We drained last fall for some plaster repair and it’s already up too high . I’m having a hard time keeping my TA down. I’ll get it down to 70, which is difficult, and a week later it’s up too high again. So it was suggested on here to keep our ph down lower. So what should it be brought down to in order to lower the TA? I’ve been bringing it down to 7.2 but if we should keep it at 7.5 then 7.2 doesn’t seem low enough for it to raise and lower. @proavia , how do you keep your TA down? How much acid do you go through?

Crazy that someone in our neighborhood bought a house that had soft water plumbed to their auto fill and wanted someone to remove it . I tried to tell them to keep it but there were too many saying how bad it was .

 

[proavia]

I live in the same neighborhood as the OP and am having the same problems. I actually have some scale already on some tiles and the waterfall . We drained last fall for some plaster repair and it’s already up too high . I’m having a hard time keeping my TA down. I’ll get it down to 70, which is difficult, and a week later it’s up too high again. So it was suggested on here to keep our ph down lower. So what should it be brought down to in order to lower the TA? I’ve been bringing it down to 7.2 but if we should keep it at 7.5 then 7.2 doesn’t seem low enough for it to raise and lower. @proavia , how do you keep your TA down? How much acid do you go through?

Crazy that someone in our neighborhood bought a house that had soft water plumbed to their auto fill and wanted someone to remove it . I tried to tell them to keep it but there were too many saying how bad it was .

It may be better to start your own thread on this so as not to fill the OP's thread with questions specific to your situation.

How often are you checking the pH? With your ever rising TA and pH, checking every other day for now would be good. We have had high temps and low humidity - both of which add to the evaporation and need to add water. In looking at your PoolMath logs for the past 2 months, it looks like you allow your pH to get to 8.2 or so before lowering it. Given your other reported test results, that is helping to increase the scaling.

Keep the CSI between 0.00 and -0.30, which will help keep the scaling down. How much scale buildup are you getting in the SWG? If the pool waterline is scaling up, the SWG probably is too.
The waterfall issue may just be efflorescence and not actually scale buildup. Post pics of the waterfall and tile line buildup.

Do you have a water softener and is it plumbed to your autofill?
What strength MA are you using and where are you getting it from?

As to how much acid it takes - that will depend on your pool volume, TA and starting pH. In my 12,000 gallon pool, I use about 4-6 cups over the course of a week. I usually add acid twice weekly now. With my CH at 550, softened fill water TA of 110 and CH <50, a pH in the 7.5-7.7 range seems to work well. With your CH of 750 and about the same fill water TA, you would need a lower pH to keep CSI in the range mentioned. You have to be pro-active in this. Don't just let pH rise to to 8.2 before taking action.

 

[mprzybylski]

It may be better to start your own thread on this so as not to fill the OP's thread with questions specific to your situation.

As Niki mentioned, we live in the same neighborhood and we often discuss all things pools and our love for TFP. I’m following along with the direction being given to her as well so I’m perfectly OK with keeping that info in the same thread for historical purposes, but if that’s frowned upon I also understand. I’m learning as well reading along. I think we’re both experiencing some of the same issues, especially the CH and our higher pH (though the pH portion is our own doing).