Refurb - Sachse Tx w/ Bi-Carb Startup

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Re: Refurb - Sachse, Tx

Thanks for the explanation Brian. This leads me to believe a TA of 225 would reduce the equilibrium ratio and result in slower pH rise (and CSI under.6). Is there a chart available for me to review the relationship between pH and TA?

What is your guidance on FC?
 
Re: Refurb - Sachse, Tx

Here is the chart:

https://www.troublefreepool.com/~richardfalk/pool/CO2.htm

Since you have no CYA, any measurable amount of chlorine is going to be more than effective. Your goal should be to keep it as low as possible while still maintaining some sort of sanitation level to prevent losing the color in your plaster. If you don't feel comfortable with this you can always add 30-50 PPM of cya and then maintain an appropriate FC level for that. It really just boils down to how much testing you want to do on a daily basis. Unless I'm missing something with your pool, it would be very difficult for you to have algae and even if you did it would be much less harmful than scale would be which is why I really only worry about the pH and TA at this point.
 
Re: Refurb - Sachse, Tx

bdavis466 said:
Here is the chart:

https://www.troublefreepool.com/~richardfalk/pool/CO2.htm

Since you have no CYA, any measurable amount of chlorine is going to be more than effective. Your goal should be to keep it as low as possible while still maintaining some sort of sanitation level to prevent losing the color in your plaster. If you don't feel comfortable with this you can always add 30-50 PPM of cya and then maintain an appropriate FC level for that. It really just boils down to how much testing you want to do on a daily basis. Unless I'm missing something with your pool, it would be very difficult for you to have algae and even if you did it would be much less harmful than scale would be which is why I really only worry about the pH and TA at this point.
Click to expand...

thanks for the chart it helps to see the areas to stay within and the ratio deltas. I noticed it is based on a CH of 300 where mine is at 160.

Ok understand on the FA. I'll keep any eye on it over the weekend and include in my measurements. The tabs should start having some visibility this afternoon. If it just stays at as little as .2 I am golden.

- - - Updated - - -

More info. My returns were pointed up slightly. They were not breaking the surface but were stirring it up pretty good. I pointed them more straight out to lessen the surface stirring. Did I do the right thing?
 
Re: Refurb - Sachse, Tx

Yep...

The only real validity to calcium level in relation to pH/TA equilibrium is because TA is measured in ppm of CaCO3 -calcium carbonate (same as calcium hardness) but the two are quite dissimilar. The whole purpose for needing any alkalinity in pools is for pH stability (if too low it will cause the pH too become erratic and crash) and to protect the cementitious surfaces from the water being too aggressive. Calcium alone cannot provide this at the typical pH levels that we must maintain in our pools. As you will soon see calcium levels do not have much impact on CSI unless they are extremely low (<125) or high (<1250). pH and TA levels are far bigger drivers of how aggressive the water may be.
 
Re: Refurb - Sachse, Tx

Reviewing chemistry may be in order for me. It was my least favorite science topic. This activity is definately (re)educating me.

Day 3
12:15 PM Readings

pH 7.8
TA 250
Temp 90
CSI .62
FC .4 (up from .2 just 4 hours ago - this indicates the tabs are starting to have influence and are replacing the sun loss)

No changes/additions at this time


 
Re: Refurb - Sachse, Tx

Day 3
4:15 PM Readings

pH 8.0 - added 13oz MA targeting 7.8
TA 250
Temp 90
CSI .82

Note: around 2:00 today as I was re-reading measuring pool chemicals on TFP, I realized I had made an error on my FC numbers. I was using the 10ml sample yielding .5 per drop and not .2. FC was 1.0 at 3:45 reading not .4 as reported. I shut the in-line chlorinator off to let FC drift down some. I will retest tonight.
 
Re: Refurb - Sachse, Tx

Day 4
7:30 AM Readings

pH 8.0 - added 13oz MA targeting 7.8
TA 225-250
Temp 89
CSI .81

Starting to see a pattern here... It does seem the pH rise overnight last night was not as great as the first two nights. Maybe the plaster is starting to settle a bit.

For those following along (and for historical records): Full pool brushing continues twice daily with area brushing/mixing when MA is added. No plaster dust at all is seen. Last night brushed with pool light on and it was all clear.
 

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Re: Refurb - Sachse, Tx

I just looked at your schedule on the first page. It looks like you are ahead of schedule!!! That's awesome - never works for me!! How long does the BiCarb start-up last? I wasn't sure on the timeline.

You're doing great!
Suz
 
Re: Refurb - Sachse, Tx

SuzfromTexas said:
I just looked at your schedule on the first page. It looks like you are ahead of schedule!!! That's awesome - never works for me!! How long does the BiCarb start-up last? I wasn't sure on the timeline.

You're doing great!
Suz
Click to expand...

Hi Suz!

Ahead of schedule makes the Project Manager (me) happy!! My PM experience had me add some buffer time for plaster.

Ahead affords a little more time to get the pool balanced and stable prior to 2 wk vacation end of August.

I will have to let Brian weigh in on the length of time for bi-carb startup. I think I have 2 weeks in my schedule with minimum two tests/adjustments and brushing per day. The weekend provided me the ability to do multiple tests. I believe getting the TA just a big lower will slow the pH rise going forward.
 
Re: Refurb - Sachse, Tx

peirek said:
Hi Suz!

Ahead of schedule makes the Project Manager (me) happy!! My PM experience had me add some buffer time for plaster.

Ahead affords a little more time to get the pool balanced and stable prior to 2 wk vacation end of August.

I will have to let Brian weigh in on the length of time for bi-carb startup. I think I have 2 weeks in my schedule with minimum two tests/adjustments and brushing per day. The weekend provided me the ability to do multiple tests. I believe getting the TA just a big lower will slow the pH rise going forward.
Click to expand...

2-3 weeks is plenty. Don't add any more bicarb and let the TA naturally fall with your acid additions. Once you get the the 3 week mark you can begin lowering the TA a little more aggressively.
 
Re: Refurb - Sachse, Tx

bdavis466 said:
2-3 weeks is plenty. Don't add any more bicarb and let the TA naturally fall with your acid additions. Once you get the the 3 week mark you can begin lowering the TA a little more aggressively.
Click to expand...

Hi Brian,

No more bi-carb, check. Does anyone need 38.5 lbs of baking soda, unopened? &#55357;&#56846; I guess my fridges will be smelling real fresh for years to come.

I noticed in pool math that as the TA drops the amount of MA needed to lower pH is less which in turn slows TA lowering. I guess lowering TA more aggressively will entail dropping pH into more normal range (7.2 - 7.6)?
 
Re: Refurb - Sachse, Tx

To lower the TA you'll drop the pH to 7.0-7.2 and maintain it in that range while aerating. As you saw on the pH/TA chart, the low pH will really be out of balance and the offgassing will make the pH want to climb. As often as you can, lower the pH back down to the low 7's and the quicker your TA will drop.

You can't just add a bunch of acid at one time because you don't ever want to drop the pH below 7.
 

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