Ph increase with SWG

[Swimgirl]

Another question about getting an SWG. Right now, I have to add about a cup a day of 10% liquid chlorine, but only have to add muriatic acid about once a week. The Ph stays pretty stable. I've heard that with an SWG, Ph tends to climb. How much is the climb? Would I be substituting my daily dosing of liquid chlorine for a daily dosing of acid? If that's the case, it doesn't seem like an SWG would really save anything in time or labor!

 

[DaveNJ]

Only speaking of my experience, acid consumption is 10oz every 10 days or so. Initially balanced the water to recommendations on TFP. Initial cost is up there so you probably would only save time & labor. There has been discussions of cost of one versus the other.

 

[chem geek]

The pH climb is generally substantial with an SWG if you do not do things to mitigate it. Having a CYA level of 70-80 ppm to reduce chlorine loss from sunlight thereby letting you lower the SWG on-time helps. Having a lower TA of around 80 ppm and a target pH of around 7.7 also helps. Using 30-50 ppm Borates can also help. If applicable, turning off other aeration features such as waterfalls, spillovers, fountains, etc. also helps.

Without the above mitigating factors, people have reported adding a quart of acid per week or more, depending on pool size. Even with the mitigating factors, you will probably find somewhat higher acid addition but perhaps not very much depending on your current water parameters (mostly pH and TA). [EDIT] As Dave just posted, with the aforementioned adjustments you can get to something reasonable. [END-EDIT]

Richard

 

[ePoolUser]

My pool is 3 years old, but I only added SWG this year in June. I had to drop the Alkalinity from 290 down to 90 and did so by July 10 and since then I have had rock steady pH of 7.6. That's 5 weeks of steady pH.

It's been so steady, I'm thinking something is wrong.

I have used AquaChem and Taylor test kits. It's always 7.6.

Has anyone else experienced this?

Cl 3.0
TA 90
CH 170
Salt 3200

 

[MikeInTN]

My pool is 3 years old, but I only added SWG this year in June. I had to drop the Alkalinity from 290 down to 90 and did so by July 10 and since then I have had rock steady pH of 7.6. That's 5 weeks of steady pH.

It's been so steady, I'm thinking something is wrong.

I have used AquaChem and Taylor test kits. It's always 7.6.

Has anyone else experienced this?

Cl 3.0
TA 90
CH 170
Salt 3200

Yep, I'm right there with you. My TA's around 80 I think, CYA's around 70 - 75, I run my SWG 4 - 6 hours a day, and my pH stays rock solid on 7.6 . I haven't had to add any acid since I lowered my TA about 5 weeks ago. I'm not going to question the pool gods, I'm just going to take it and run!

 

[xjrguy]

Believe it or not but I have had a span of 8 months of PH at 7.2 - 7.4 without having to add a drop of acid.

Our pool also has a SWG (Jandy Aquapure 1400), Jandy 60 sq/ft DE filter and (2) Stealth pumps. Pool also has a spa with spillover.

I check the pool water weekly and over the past eight months it's been PH stable.

My wife and I couldn't believe it.

Our pool is 2 years old and is of Gunite construction.

Is that a record?

I use the test equipment that has liquids, not strips and I believe it's a 6 way test kit.

 

[chem geek]

xjrguy,

That does seem to be a record. :-D What are the TA and CYA levels in your pool? Do you have 50 ppm Borates in the pool? Do you ever add any chemicals to the pool, even MPS non-chlorine shock?

Richard

 

[xjrguy]

TA I have no idea I have never tested that.

CYA is around 60 to 80 PPM

Don't know about the Borates.

I do add chemicals (manual shock) in small plastic bags sold at the pool store. I only do this rarely.

I've never used "Boost" on the Jandy and normally keep the SWG at 80%. Pump runs from 8am to 4pm daily.

Pool is a 16 x 36 rectangular with a 9.5 ft deep end.

I am religious about backwashing and I just thoroughly cleaned the filter out this past weekend (that was fun and enlightening since it was the first time I've done that since the pool was redone 2 years ago)

Other than a minor algae bloom that sometimes occurs on the walls of the pool (I don't brush daily) the water has been crystal clear. (pool ran low on salt and the SWG wasn't generating chlorine until I noticed semi green walls, LOL)

We are located in Southern California.