Recommended Calcium Hardness Levels

[olevelo]

Pretty much everywhere else recommends CH to be 200-400, including in my K-2006 kit. But the Pool Math app says for plaster SWG I need to be between the 250 and 650, ideally 350-550. Why is Pool Math so different?! Mine is reading about 210 (was 250 total hardness with strip tests), and I'm already fighting a scaling problem so it seems like a terrible idea to raise it even more. Also I have a heater and elsewhere on the site it recommends keeping CH around 200 for the health of the heater.

So first of all why is it so different, and second, can I change the recommended ranges in the app so it doesn't constantly yell at me for being bad?

 

[Newdude]

So first of all why is it so different,

On the east coast with more rain than evaporation, we have to add CH to stay in range.

Some places like the southwest have high CH fill water and all evaporation and need to drain every year or two to keep the levels down.

Moral of the story, pretty much no matter where you are, it won't stay where it's at for long. So we allow a wide range to accommodate everyone.

can I change the recommended ranges in the app so it doesn't constantly yell at me for being bad?

No but go to settings, scroll down to advanced settings and turn off ideal range. That'll help a good deal of it. There is no 'more ok' than ok. Anything in range is ok if your CSI agrees. Ideal range is simply where most pools tend to land and if yours is off a bit, it's fine.

 

[olevelo]

Moral of the story, pretty much no matter where you are, it won't stay where it's at for long. So we allow a wide range to accommodate everyone.

But the bottom of the ideal range is MUCH higher than everyone else says. And the top end is even more. None of the other levels are set to "it's going to change so here's something different to accommodate for that". Also, I've had this pool for over a year and my hardness level has never changed and I've never added anything (granted I was using strip tests, but regardless of how right they were, the readings have always been the same...literally the only reading that never changes!).

No but go to settings, scroll down to advanced settings and turn off ideal range. That'll help a good deal of it. There is no 'more ok' than ok. Anything in range is ok if your CSI agrees. Ideal range is simply where most pools tend to land and if yours is off a bit, it's fine.

I don't want to turn off all of the ideal ranges. That's part of the reason I just paid the $8 for the app, so I have all of that information.

And I don't think ideal ranges are "where most pools tend to land". If they just landed there no one would have to do any maintenance. Ideal is supposed to be what's healthy for the pool, not what's common.

 

[Donldson]

I was using strip tests, but regardless of how right they were, the readings have always been the same...literally the only reading that never changes!

And this is what you think accuracy looks like?

 

[olevelo]

And this is what you think accuracy looks like?

I didn't say they were accurate, and I even made mention of that. I said they didn't change. The point I was trying to make was that he said "no matter where you are it won't stay where it's at for long".

 

[Donldson]

I didn't say they were accurate, and I even made mention of that. I said they didn't change.

Yeah, and if you dip a rag in the water it will change the same color each time. I'm not saying it will give you any useful information, but it won't change!

 

[olevelo]

Yeah, and if you dip a rag in the water it will change the same color each time. I'm not saying it will give you any useful information, but it won't change!

There are multiple instances of the "experts" here agreeing that while strips can't be trusted to give you an accurate reading, they can still give you a consistent reading in order to see if things change. And also the K-2006 was in the same ballpark of the strip test I did (really for nearly everything, but most applicably the hardness, assuming the vast majority of my hardness is calcium).

 

[Leebo]

You mentioned the K-2006 kit; are the pH and TA values in your PoolMath logs derived from this Taylor kit or from test strips? The reason I ask is that very high TA and pH levels can indeed cause issues inside your SWG cell, potentially leading to scaling as you mentioned……especially inside of your salt cell.

 

[Donldson]

There are multiple instances of the "experts" here agreeing that while strips can't be trusted to give you an accurate reading, they can still give you a consistent reading in order to see if things change.

[citation needed]

 

[olevelo]

You mentioned the K-2006 kit; are the pH and TA values in your PoolMath logs derived from this Taylor kit or from test strips? The reason I ask is that very high TA and pH levels can indeed cause issues inside your SWG cell, potentially leading to scaling as you mentioned……especially inside of your salt cell.

The latest values are from the K-2006, and yeah the TA is high, and has been for awhile according to the strips. The pH had been fine but just jumped the last week or so.

I was going to attempt a no-drain acid wash (researched it here thoroughly so have read every thread on it) starting yesterday but due to various reasons need to wait a couple more weeks. So not doing anything aggressive to battle the TA till after that's done, but I did add some muriatic acid today (first time I've used MA, I had been using Clorox PH Down).

 

[generessler]

I made a related comment about CSI some time back and also got advice about ideal vs acceptable. Maybe the replies are helpful.

I'm sure someone will ask you to post complete test results and add a sig block with more pool info so they can help. Scaling with CH in the 200's points to something else wrong.

 

[Leebo]

The beauty of the CSI (Calcium Saturation Index) is that it takes into account the balance between multiple variables. Currently, with your elevated TA, it's wise to keep calcium a bit on the lower side as it compensates for the higher alkalinity and helps maintain a balanced water chemistry. Additionally it’s wise to be very mindful of your pH as that’s also really pushing things upward causing your risk of scale to increase.

However, as you begin to reduce your TA and especially when your water temperature drops, you might notice a decrease in your CSI. In this scenario, slightly elevating your calcium level can be beneficial in maintaining the balance.

It's crucial to remember that you don't always have to aim for perfect "ideal" numbers across the board. Striving for the recommended levels will ensure a fantastic pool experience and keep your surfaces in great shape. The "ideal" values are there for those who wish to fine-tune their pool chemistry to the max. But always prioritize a balanced pool over perfect numbers!

 

[olevelo]

I made a related comment about CSI some time back and also got advice about ideal vs acceptable. Maybe the replies are helpful.

I'm sure someone will ask you to post complete test results and add a sig block with more pool info so they can help. Scaling with CH in the 200's points to something else wrong.

Thanks. I had linked my app to my profile and based on Leebo's comments it seems he was able to see the test results. That thread was helpful, and some things to think about as it cools off (eventually!).

 

[olevelo]

The beauty of the CSI (Calcium Saturation Index) is that it takes into account the balance between multiple variables. Currently, with your elevated TA, it's wise to keep calcium a bit on the lower side as it compensates for the higher alkalinity and helps maintain a balanced water chemistry. Additionally it’s wise to be very mindful of your pH as that’s also really pushing things upward causing your risk of scale to increase.

However, as you begin to reduce your TA and especially when your water temperature drops, you might notice a decrease in your CSI. In this scenario, slightly elevating your calcium level can be beneficial in maintaining the balance.

It's crucial to remember that you don't always have to aim for perfect "ideal" numbers across the board. Striving for the recommended levels will ensure a fantastic pool experience and keep your surfaces in great shape. The "ideal" values are there for those who wish to fine-tune their pool chemistry to the max. But always prioritize a balanced pool over perfect numbers!

Thanks. Right now my CSI calculation is just slightly above ideal, which is why it's a little baffling I keep having the scaling problem. Part of it is that I've had some bad spots ever since I bought the house and got some off with pumice stone but a lot I haven't been able to, hence the acid wash attempt. But I have had some reappear after scrubbing it off too. I just want to get it "clean" then balanced and see where it goes from there! Other than the scaling the pool has always been beautifully clear with little maintenance. And just using test strips to monitor.

 

[olevelo]

I should also mention that I'm kind of paranoid about my PH and calcium levels due to my heater, which I just had installed last year (previous owner had one but ripped it out, presumably because it broke), and I've read so many horror stories about them breaking due to incorrect levels. And one of the Pool School articles here said to keep CH around 200 for a heater, which contradicts the 250 min and 350 min ideal.

 

[Newdude]

I don't want to turn off all of the ideal ranges. That's part of the reason I just paid the $8 for the app, so I have all of that information.

Don't chase ideal levels. Again, anything in range is equally ok if your CSI agrees.

Ideal is supposed to be what's healthy for the pool, not what's common.

'Ideal' PH for liquid chlorine based pools is a low 7, while ideal PH for SWG pools is a high 7. That's where they tend to sit when TA is adjusted accordingly. But if your LC pool wants to sit in the high 7s due to a waterfeature, spillover, etc, it's totally OK to buck the ideal LC PH. It's literally nothing more than the most common occurrence.

This is a favorite ploy of the pool store. They get you chasing a better than ok TA/PH and that's when the Rollercoaster starts. PH up raises your TA also and then you need to lower the TA which lowers the PH and they get to sell you more PH up.

which is why it's a little baffling I keep having the scaling problem

Run the TA on the low side of the range to reduce the scaling. 'Ideal range' be darned. The TA that stops scaling is your actual ideal level.

 

[olevelo]

Don't chase ideal levels. Again, anything in range is equally ok if your CSI agrees.

'Ideal' PH for liquid chlorine based pools is a low 7, while ideal PH for SWG pools is a high 7. That's where they tend to sit when TA is adjusted accordingly. But if your LC pool wants to sit in the high 7s due to a waterfeature, spillover, etc, it's totally OK to buck the ideal LC PH. It's literally nothing more than the most common occurrence.

This is a favorite ploy of the pool store. They get you chasing a better than ok TA/PH and that's when the Rollercoaster starts. PH up raises your TA also and then you need to lower the TA which lowers the PH and they get to sell you more PH up.


Run the TA on the low side of the range to reduce the scaling. 'Ideal range' be darned. The TA that stops scaling is your actual ideal level.

For what it's worth, this is my 3rd pool and I haven't set foot in a pool store in 12 years (a couple years after building our first pool). So I'm not chasing numbers based on them, but the fact that there's published ideals here and I'm an engineer so I need the numbers to all match.

 

[Newdude]

but the fact that there's published ideals here and I'm an engineer so I need the numbers to all match.

There's no such thing as a perfect set of #s across the land. We play hand grenades here, not horseshoes. Then we custom tailer levels for individuals climate/location/pool type.

For your CH, I'd aim for mid range (350) expecting it to lower with the 50+ inches of rain you get each year. Bump it back up when it hits 300. You're free to go higher, again, knowing full well it will come down. In places with high CH fill, we advise the opposite. We tell them to balance originally to 250 knowing it will rise into range before long, to delay the eventual drain needed when it's above range.

Manage PH in the low 7s until your TA is a 60 and that will help the scaling. Once the TA is lowered, then only adjust the PH when it's no longer a 7. Your pool will tell you if it likes high or low range at that point.

 

[olevelo]

There's no such thing as a perfect set of #s across the land. We play hand grenades here, not horseshoes. Then we custom tailer levels for individuals climate/location/pool type.

For your CH, I'd aim for mid range (350) expecting it to lower with the 50+ inches of rain you get each year. Bump it back up when it hit 300.

Manage PH in the low 7s until your TA is a 60 and that will help the scaling. Once the TA is lowered, then only adjust the PH when it's no longer a 7. Your pool will tell you if it likes high or low range.

Thanks for the advice! I'll try all of this!

I'd still like to be able to set custom ranges in the app for my sanity.

 

[Newdude]

I'd still like to be able to set custom ranges in the app for my sanity.

That we can't do. But if it helps any, poolmath doesn't know your personal details and what works best for your situation. It only knows the general recommendations which is the staring point, before climate, location and fill water are taken into consideration.

So if she talks smack, smile that you know better.