Mixing acid and Baking soda in a Stenner ?

[MaverickFL]

I have used CO2 to control pH in the past but that was in a calcium reactor. It would add a bunch of additional control parameters and possible failure points with a pH controller, probes to calibrate and replace, solenoid valves, regulator, tubing to replace, injection point and/or reactor, probe point and CO2 tanks to swap out for full ones. I wouldn’t add it to my pool but then I don’t have a water feature.

lve only Increased my TA once and that was after a major rain event. Normally I’m actively trying to reduce it rather then increase it. The vast majority of us have enough TA in our top up water. Have you measured your tap waters TA?

Good things to consider. Here in south Florida I think rain water would be more the consideration than tap water. I haven't added a drop of tap water all summer. I would imagine the rain water is fairly low TA as well but the major factor seems to be the regular addition of acid.

 

[MaverickFL]

From the reference you provided.

Using Air and Acid to Quickly Get Perfect pH/Alkalinity

You really can nail down pH and alkalinity using just air and muriatic acid.

www.aquamagazine.com

I've done a bit of reading since last night. I'm not a chemist, high school chemistry was as far as I went, so I can't proof your computations but with all the reading I've been doing I'm convinced that your explanation is solid and that there is a fair amount of misinformation out there regarding this that was complicating my initial thinking on this. Thanks James

 

[PoolStored]

I've done a bit of reading since last night. I'm not a chemist, high school chemistry was as far as I went, so I can't proof your computations but with all the reading I've been doing I'm convinced that your explanation is solid and that there is a fair amount of misinformation out there regarding this that was complicating my initial thinking on this. Thanks James

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

www.troublefreepool.com

 

[MaverickFL]

The TA is the problem in that case. If you let your TA drift down to 60ppm your pH rise will significantly slow and drop. I’m not familiar with the differences between CSI and LSI so would need to let someone else deal with rhat. Assuming they are closely related I keep my CSI very close to zero while maintaining a TA of 60 and pH of 7.8

Interesting call out. I didn't actually realize there was a signifcant difference between CSI and LSI and I like the Orenda calculator for LSI vs the Pool Math calculator for CSI because its a lot easier to see 'what if' scenarios, but since discussion here tends to use CSI I'm going to switch to that instead. Plugging my numbers into the PoolMath calculator, I would have to bump my CH to over 800 to get my CSI down close to 0 let alone slightly above with a TA of 50 and a PH of 7.8. I guess those here who have there TA low are running PH high and pushing closer to the lower end of the CSI acceptable range ?

 

[JamesW]

 

[MaverickFL]

I was trying err more on the safer side of 0-+30 for two reasons, I'm not completely comfortable that I can keep the pool in balance yet, and perhaps more to avoid further research, ie. what are the effects the further to the negative side of the scale you slide. WHo decided -.31 is bad and -.29 is safe?

 

[Bperry]

Interesting call out. I didn't actually realize there was a signifcant difference between CSI and LSI and I like the Orenda calculator for LSI vs the Pool Math calculator for CSI because its a lot easier to see 'what if' scenarios, but since discussion here tends to use CSI I'm going to switch to that instead. Plugging my numbers into the PoolMath calculator, I would have to bump my CH to over 800 to get my CSI down close to 0 let alone slightly above with a TA of 50 and a PH of 7.8. I guess those here who have there TA low are running PH high and pushing closer to the lower end of the CSI acceptable range ?

Ah, I should have caught your were trying to stay above zero. Everything I’ve read says to stay slightly negative to avoid scaling. I don’t specifically target a specific pH but it just like to kinda top out at 7.8 most of the time. If I try and lower it below that too much it’ll race right back to 7.8 and hover there. Have to add acid a little bit as it hits 8 very slowly compared to how fast it rises from 7.2 to 7.8

 

[JamesW]

0.00 is perfect.

Anything above risks scale and anything below risks dissolving calcium carbonate from the plaster.

It’s an exponential scale and it has generally been accepted that being within about 0.3 above or below 0.0 is “safe”.

Safe is a relative term and you have to consider the normal fluctuations and the long term effects.

Within about 0.3 above or below will generally have very slow effects for corrosion or scale.

I don’t have any definitive studies that show the long term effects of maintaining any specific level of CSI.

My observations have been that once you go significantly above or below 0.00 by more than about 0.30, you begin to have a higher risk of noticeable problems.

 

[MaverickFL]

0.00 is perfect.

Anything above risks scale and anything below risks dissolving calcium carbonate from the plaster.

It’s an exponential scale and it has generally been accepted that being within about 0.3 above or below 0.0 is “safe”.

Safe is a relative term and you have to consider the normal fluctuations and the long term effects.

Within about 0.3 above or below will generally have very slow effects for corrosion or scale.

I don’t have any definitive studies that show the long term effects of maintaining any specific level of CSI.

My observations have been that once you go significantly above or below 0.00 by more than about 0.30, you begin to have a higher risk of noticeable problems.

Thats pretty much in line with everything I've seen thus far. My thinking is that since its an imperfect science, although neither condition is desirable, I'd rather error more on the plus side of having a small build up since its noticeable and more correctable vs. etching, corrosion etc. and, I don't want to digress the thread but Im also having some issues with what appears to be plaster sediment (blue/tan) in my vacuum bag on a weekly basis, 2 years after the finish was done. I've had a lot of issues with this finish, initially significant issues with staining from 'organic' material that got in the mix, that lasted about 6 months and is still going on to some degree, and I'm concerned that this is going to turn into a warranty issue with NPT, so I'm trying to rule out any possibility that water balance (negative) is the issue.

ANyway back to the poolmatch CSI calculator, if you try to get that very close to zero with the other nuimbers constant you will see the CH bump up very high

 

[JamesW]

 

[reggiehammond]

Have you considered just running the waterfall only while you’re actively enjoying it?
Many here do just that and avoid the aeration issues that constant use brings forward.

 

[MaverickFL]

View attachment 459772View attachment 459775

THe suggestion was to run TA at 50 to keep the ph from running up, and during swim season I wouldn't keep my ph above 7.8, that could lead to sacrificing bather comfort for the sake of the chemicals which seems backwards to me. Also my borates are at 45, supposedly to help stabilize the PH. With those 3 changes at 800ppm CH I am still just slightly below zero (-.12) at 75 degrees.

 

[JamesW]

In my opinion, any pH up to 8.3 would be comfortable for swimmers.

The TA at 50 ppm was a bottom limit but 60 or 70 would be better especially if you are using borates.

In any case, you should have enough information at this point to make an informed decision about what will work best for you.

 

[MaverickFL]

In my opinion, any pH up to 8.3 would be comfortable for swimmers.

The TA at 50 ppm was a bottom limit but 60 or 70 would be better especially if you are using borates.

In any case, you should have enough information at this point to make an informed decision about what will work best for you.

Agreed, this has been very informative. The more I know about pool chemistry the more I realize there is to know. Somewhat depressing actually. Just kidding, I appreciate all the knowledge that is shared here, and even though I am scratching the surface I feel that I already know more than my last pool service about balancing chemicals. Swim season is over here so I'm going to use the opportuntiy to work with the suggestions here and see how it goes.

 

[MaverickFL]

Have you considered just running the waterfall only while you’re actively enjoying it?
Many here do just that and avoid the aeration issues that constant use brings forward.

Hey Reggie,

Yeah, I have given it a lot of thought lately because of all the hassle coming up around it. As I mentioned this is a courtyard home, the entire house wraps around the pool and the waterfall is at the center. My wife and I both work from home, both of our offices look out at the pool as does virtually every room in the house, so we are really enjoying the sound and the view literally all day. On top of that, in order to keep the flow down to a minimal amount, I've used both the settings on the valve actuator to adjust the flow based on High/Low pump speeds, so I have no way to turn the waterfall off at this point actually. Before I adjusted the flow down I was probably adding about a gallon a week of acid. It looked great but was just too much. This is actually the compromise mode