My numbers w new 4 month old plaster pool

[Jazzlover]

Any suggestions welcomed

FC 8
PH 7.5 finally leveling out
TA 90
CH 300
CYA 50
Salt 3500
Temp 83

Acid consumption is finally slowing down....been working on slowly raising CYA but not wanting too high, right? The pool gets full sun approx 4-6 hrs a day-Will the FC burn off naturally or should I add some water to lower? Thanks in advance!

 

[JamesW]

You're doing well. I think that you could allow the pH to run closer to 7.6 to 7.8, the TA at about 60 to 80 and the CYA at about 60 to 70.

Maintain your chlorine according to this chart. Are you measuring for combined chlorine?

Keep your CSI at about -0.2 to 0.0. Use the lower end of the range if your SWG runs more than 50 % of the time.

You might want to consider adding borates.

If your chlorine is running too high, then you need to turn the SWG down.

How is your water at 83 F if the heater is not in yet?

 

[257WbyMag]

You're looking pretty good. Your FC is a little high for a CYA of 50. Dial down your SWCG and it will drift down on it's own.

Your CYA is a little low for what we recommend for SWCG pools. We recommend a CYA of 60 to 80 ppm for salt pools so you might want to bring that up a tad. With a higher CYA, your cell doesn't have to work so hard to keep up with what the sun burns off.

A pH of 7.5 is fine. Keep in mind that you have new plaster and this will continue to cure for up to a year. Curing plaster means chasing a high pH. Couple that with a SWCG which also causes pH to climb, and it just proves that you need to be vigilant in keeping your pH in check. I see no need to add borates at this time.

 

[JesseJames]

That is great water temp for this time of year. My solar is on and the water temp yesterday was only 72 degrees.

 

[frustratedpoolmom]

You're looking pretty good. Your FC is a little high for a CYA of 50. Dial down your SWCG and it will drift down on it's own.

Your CYA is a little low for what we recommend for SWCG pools. We recommend a CYA of 60 to 80 ppm for salt pools so you might want to bring that up a tad. With a higher CYA, your cell doesn't have to work so hard to keep up with what the sun burns off.

A pH of 7.5 is fine. Keep in mind that you have new plaster and this will continue to cure for up to a year. Curing plaster means chasing a high pH. Couple that with a SWCG which also causes pH to climb, and it just proves that you need to be vigilant in keeping your pH in check. I see no need to add borates at this time.

Ditto -
Jazz, you're numbers look good and I wouldn't sweat the small stuff.

 

[Jazzlover]

Oh, forgot to mention we've been running the heater on occasion and just last weekend. Thanks for all the comments...I feel like I might just be able to do this thing on my own....only because of you guys!!!!

thanks

 

[JamesW]

The primary reason that I suggested a higher pH and a lower TA was to reduce the amount of carbon dioxide in the water. The amount of carbon dioxide in excess of that which is in equilibrium with the air can be reduced by about 50 %, and should reduce the corresponding carbon dioxide loss rate and consequent pH rise by about as much. Based on the particulars of this pool, I felt that a lower level of carbon dioxide would be especially beneficial.

1) The pool is heated. Warmer water will not hold as much carbon dioxide as cooler water.
2) Two blowers, two bubblers, two waterfalls, eight jets and the SWG will create aeration substantially in excess of most pools.

The reason that I suggested adding borates is that using an SWG in a plaster pool is especially challenging due to the competing need to maintain the CSI high enough to protect the plaster and low enough to prevent excess scaling in the salt cell. Borates are particularly good at buffering pH from increasing. 50 ppm borates (at a pH of 7.8) have the same pH buffering capacity on the upside as 221.6 ppm of TA have at buffering the pH on the downside. The boric acid sequesters the hydroxides created in the cell and prevents them from converting bicarbonate into carbonate.

B(OH)₃ + OH^- <> B(OH)₄^- (pKa = 9.14)

Also, keeping the CSI as close to 0.0 as possible without scaling the cell will reduce pH rise due to the new plaster.

[edit]When one is going to keep the CSI slightly negative in a plaster pool to prevent scaling in a salt cell, or for any other reason, then the plaster can be at some risk for etching and premature dissolution. In these cases, a higher pH will help reduce the risks, because a pH of 7.5 has about twice as many hydrogen ions as a pH of 7.8.

It is the hydrogen ions that react with the calcium carbonate in the plaster to form soluble calcium bicarbonate. This reaction causes the pH to rise. Maintaining a higher pH will reduce the amount of pH rise due to this reaction.

Maintaining a neutral to positive CSI is important to achieve maximum longevity of the plaster. [end edit]

 

[Jazzlover]

Thanks everyone...(now I see confusion on not delivered heater/chiller) we also have propane which is how it was heated occasionally at times this winter(at an astounding price)... I think we are done heating the pool for this season w propane, thanks again!Now to figure out how to adjust the SWG....any suggestions? Pool was finished & we had no instructions so we've been learning as we go.....thx again!

 

[JamesW]

Were you given a copy of the owner's manual?

How much time does the pump run per day?
What percentage do you have the salt cell set for?

 

[Jazzlover]

No, on the owners manual....or any other equipment. Pump runs 8 hrs a day and the SWG is set on 50%

 

[JamesW]

Just click on the link I posted above for a copy of the owner's manual. Adjust the percentage down to the correct level.

 

[Jazzlover]

Sweeeet! I forget just about everything's available on the web- will work on this tomorrow- thanks again!