SWG on order, question on TA

[JonoVegas]

I pulled the trigger today and ordered my SWG today! (Circu Pool RJ45+)
Current readings:
FC 3
PH 7.6 (PH has been very stable)
TA 100 (should I lower TA because of new SWG coming?)
CYA 70
CH 350
Pool Temp 54
CSI -0.12

Should I lower my TA? Some readings seem to suggest if PH is stable not much need to adjust the TA, but others seem to indicate TA should be more in the 60 to 80 range for SWG.

We do make extensive use of a solar cover to raise and then maintain heat. For some reason here in Vegas desert when temps get to 110 the pool feels cold if its not at least 90.

So as an aside when I start runing in SWG mode do I need to factor in the solar cover will be on the majority of the time when not swimming or certainly most evenings to avoid heat loss?

 

[wireform]

Solar cover will have no bearing on the SWCG. I don't see a CC in your list . Don't forget to order the Taylor K-1766 salinity test kit. Test the water before you drop any salt to see what have first.

 

[ajw22]

Your TA is fine and your CSI is fine for a SWG.

Solar cover doesn't affect the SWG.

 

[mknauss]

FC loss will be a little less with a solar cover on the pool during the summer. But when you take it off the pool, the FC loss will jump. So you will be adjusting the SWCG % up and down more that most of us.

I use a solar cover in April and May and again in Sept and Oct. But the other months it makes the pool water way too hot. We look for 86-88 F water temperature in the heat of summer.

 

[Rattus Suffocatus]

So I am still considering a SWCG .. I have been running a very stable CSI with TA at 120-130 (depending on the day...). Is there an upper limit to TA with the cell, or is the concern more about having to monitor and correct pH more until it comes down? I have CH at 225 which I had planned to let drift up with the Tucson water, pH at about 7.7. Should I try to acid down the TA if I put a cell in? Or am I okay at the high end of TA with balanced CSI? I do know I will have to bump up CYA a bit since I am stable at 40, but that probably realistically buys me a couple of weeks of tablets before I order the cell. I have quite a bit of LC to use up before I buy a cell too...

The crazy bat #$@# run on everything including now pool chlorine makes me think that I should spend the money despite probably being never able to retire.....

 

[ajw22]

Nothing about a SWG requires changing your TA.

With a SWG you want the CSI to be negative to not scale the SWG. Adjusting the CH and TA can effect the CSI.

 

[mknauss]

Only caveat -- I see with my SWCG that when my TA gets to 90 or above, the cell tends to shed calcium flakes. Regardless of CSI.

My observations only.

 

[JoyfulNoise]

Only caveat -- I see with my SWCG that when my TA gets to 90 or above, the cell tends to shed calcium flakes. Regardless of CSI.

My observations only.

It's not just you, Marty. TA does need to be adjusted down with an SWG. The problem is, INSIDE the cell, the CSI is very different than in bulk pool water. With high TA and aeration, you'll get faster pH rise inside the cell and so there's more potential for scaling. With current reversal, the cell tends to stay clean but you'll get more snowflakes out of the returns. Calcium hardness is only one part of the equation. If the cell pH rises much above 10 (and it can easily do that) and if there is sufficient levels of carbonate ions available (CO3--), then you will get calcium carbonate precipitation. The higher the TA and pH, the more carbonate anions are available.

You can live with higher TA but it will almost always manifest itself as faster pH rise in the pool especially when the summer swimming months start up and the water is "aerated" more.

 

[wireform]

It's not just you, Marty. TA does need to be adjusted down with an SWG. The problem is, INSIDE the cell, the CSI is very different than in bulk pool water. With high TA and aeration, you'll get faster pH rise inside the cell and so there's more potential for scaling. With current reversal, the cell tends to stay clean but you'll get more snowflakes out of the returns. Calcium hardness is only one part of the equation. If the cell pH rises much above 10 (and it can easily do that) and if there is sufficient levels of carbonate ions available (CO3--), then you will get calcium carbonate precipitation. The higher the TA and pH, the more carbonate anions are available.

You can live with higher TA but it will almost always manifest itself as faster pH rise in the pool especially when the summer swimming months start up and the water is "aerated" more.

Thanks, Great info.

 

[JoyfulNoise]

Also, borates are particularly helpful because the pKa for boric acid / borate anion buffering is approximately 9. That essentially means you get the maximum buffering capacity at a pH of 9 and that tends to hold down the pH rise inside the cell. Keeping the pH below 10 reduces the risk of calcium and magnesium scaling (insoluble magnesium hydroxide precipitates at a pH of 10.2 or so).

 

[Rattus Suffocatus]

Thanks. I have actually asked a version of this question three different times/ways on this board and always received a slightly different answer. I think this might be the best so far. Compared to my neighbors who have already had the tile cleaners in for a pool that is only 6 months older than mine, I am very proud in how I've kept the tiles from scaling but just a little bit. (I think you can't avoid some here in Tucson no matter what). HOWEVER, I obviously have used my solar cover as the winter cover and at the last full sweep cleanup I did of the pool (been doing it about every six weeks), it literally looked like I had shaken a 10# bag of calcium flakes into the xeroscaped gravel. I knocked as much as I could off of the cover and used a gallon of muriatic acid to take off a lot of the rest (I need to go over it again the same way, and yes polyethylene seems to be okay with the 6:1 mixture of water to muriatic acid I used...) ... but yes, I know the dandruff regardless.

I prefer to modify water chemistry slowly and carefully. I decided to get TA down to 70 on the hot tub as an experiment to see what it would take to bring down the pool to the 70-100.. and if I scale up, I have a LOT of acid to add. I'd rather do it over time than all at once plus aeration, so I guess that is the plan for the salt cell going on.

The borates are a fantastic idea except for one problem for me... We somehow ended up with three dogs, two of them really prefer to drink out of the pool because... well they are dogs... so I am going to hold off on boric acid for the time being.

Thanks for the insight though. Hopefully I will be able to keep getting LC from Walmart and E-Konomy in the mean time. I have about a months worth at this time (12 gallons+) but the demand rate is already starting to go up for the pool.

 

[ajw22]

If you are going to add borates get your TA down to 60-70 before you add the borates.

 

[JoyfulNoise]

I've honestly never believed in the whole "borates will kill your dog" issue. While I appreciate the effort made in the article on borate safety to highlight the issues, I simply don't believe you will harm an animal as long as they have a supply of fresh water available (most mammals have very well-developed excretion of minerals through their kidneys). Most of those epidemiological tests are done on animals that are confined to ingesting a specific amount of the compound in question without any other factors involved. So there's a huge difference between a lab animal and a family pet.

Honestly, here in the southwest, you have a much greater chance of your dog contracting and dying from Coccidioidomycosis by sniffing around in the dirt than any chronic issues caused by borate exposure. But, since I'm not a dog-person, you have to form your own opinion about it....

 

[Rattus Suffocatus]

My dogs are stupid. They prefer to drink out of the pool than a fresh bowl given to them. (Ok, not the Lab, but a Lab is more than a dog.)

I might end up doing borates, but so far I've done the "Zen TFP" method of adding AS LITTLE AS POSSIBLE to the water (there is enough crud in the water here to start off with and the autofill will add more!). So I'd really have to have a reason to do borates first. Maybe I should experiment on the hot tub as it's touchier to start off with anyway. The dropping TA to the low end on the tub is actually my experiment for the pool now because if I completely bung it up, it's a 250 gallon refill.... Plus the dogs know to stay out of the tub. The tub is MINE. The pool... well, is my wife's that I do the work on...

Honestly the reason that TFP works so well is because of the concept of adding as little Crud to the water as possible. Yes that is a simplification, but it works on many levels.

Maybe the dogs won't like the taste of the water with borates in it too, who knows? Anything in moderation is okay. And you are probably correct that small amounts in PPM would probably do nothing to them over their short lifespans. Frontline is fed to them.. it's the same chemical as you treat houses for termites with. It supposedly is okay for mammals because the central nervous system paths that it short circuits in bugs don't exist in higher mammals. But who knows... Yet it's used all the time...

I like dogs for the most part. The one that was given to us could go right to the shelter IMHO, but even she is getting better now that she's approaching a year old. But I like breeds that are bred to obey humans because then at least something listens to me (like my Labrador, no better breed. The Springer Spaniel is okay because she loves people. The Australian Shepard: I wish I cold give her to a rancher). We also ended up with three cats. I am not really a cat person, but one has totally adopted me since I saved her life as a kitten, so I don't have a choice. They stay away from the pool, obviously!

I think because we had to give up our 13 chickens when we left Iowa the wife and kids have the zoo as a substitute...

I dunno. The massive lack of time (I'm busier than ever!) and the fact I don't want to spend a grand after losing 100 in my 401k is slowing down my initial push to get the Circupool. But I really ought to.... In the meantime I can slowly get the water ready for it. Thanks for your help!