Help me weigh pros and cons of SWG

[Newdude]

+1. You will get it as close as possible to your target, both now and every spring with the K1766. After that, no matter how much you know better, you can't argue with the cell.

The problem with just using the cell in the first place is that it could be massively off and you'd have to drain.

 

[TexEdmond]

salinity display on the RJ30+ accurate enough to go off of, or should I get the K-1766

Your choice. Strips and onboard diagnostics aren't as accurate. I used strips to get mine started up and just watch the SWG numbers. If they start creeping up, I know it's time to put more water in the pool because evaporation snuck up on me.

SWGs work on a very broad range of salinity levels, and it's the widest "safe range" of any of the numbers we track here, and it almost doesn't matter whether the number on the panel is accurate or not; the cell either makes chlorine or it doesn't. It really almost is a "set and forget" value unless you're getting loads of rainfall and having to drain to compensate. I got so OCD about all the other numbers on my pool during my first TFP season, I give myself permission to "let it be" and just watch for error lights or rapid FC loss.

Also consider during the off season in Arizona you may not fully close the pool, and the water may get too cold for the SWG to operate. You'll be manually dosing the pool with bleach, which raises salt to compensate for some of the loss during swim season.

You definitely don't need to target "a number" like you would TA or CYA.

 

[Oly]

Now into my second season I have observed that a dropping salt reading from my cell's running calculation despite my K-1766 tested level is likely due to scale buildup on the plates. I have also observed a change in the calculated salt ppm at different flow rates or pump rpm during generation. Higher rpm, flow rates during generation results in a lower salt ppm calculation on my unit, 2900ppm at 2300 rpm vs 3400ppm at 1350 rpm, Tested level is 3400ppm.
I now schedule all my generation time at low rpm for consistency and to avoid a low salt shut down.

 

[wayner]

Other than the initial cost, there is just no downside to using a SWCG.

The only change I would make to your schedule is to never run below the speed that turns on the SWCG. For me this is 1200 RPM. I run my pump 24/7, most of the time at 1200 RPM. I love that I am making a little chlorine all the time and that I am skimming all the time. To do this, costs me less than $20 bucks a month.

When you get out of a chlorine pool, I feel like I need to take a shower. When I get out of a saltwater pool, I feel like I just took a shower.

Quit thinking about it and do it.

This is absolutely true. I don't understand why every pool is not saltwater these days.

 

[TexEdmond]

I don't understand why every pool is not saltwater these days.

Because service calls and selling wildly overpriced chemical treatments are a huge profit center for pool installers.

 

[Katygreys]

Any comments on the flagstone part of the initial question?

 

[Jimrahbe]

Any comments on the flagstone part of the initial question?

K,

I said this a few times before, but here it is again...

I have a rent house pool that has Flagstone coping. The flagstone started to shed very thin layers of sand within a few weeks of being installed. At that time, the pool was a choline tablet pool. It stayed that way for about 3 years before I switched over to saltwater. During those three years the flagstone continued to shed. Some stones shed, and some did not. You can actually look at the stones and see which ones are going to shed and those that don't.

Nothing changed after I converted to saltwater. It has been about 8 or 9 years now, and the good stones are still good, and the bad stones still shed. The saltwater made absolutely no difference. I will never use flagstone coping again, but it is not because of the saltwater, it is because of the quality of the cheap stone.

The point of this story is that I can take you over to the pool and show you the results. I doubt that anyone can take me to a pool where the saltwater was responsible for any damage. It is almost always third- or fourth-hand hearsay that is responsible for the myth of saltwater damage.

Thanks,

Jim R.

 

[Katygreys]

Thx Jim. Contemplating the switch. Only concern was the flagstone issue/nonissue/myth/whatever.

 

[Newdude]

I had a flagstone patio and it weathered in spots too far away to blame cannonballs. It was from the elements. I actually really liked it as it gave certain pavers some real character, but I probably wouldn't have liked it doing so on the coping.

 

[Katygreys]

I’m curious what the scientific rationale would be to support the notion that saltwater increases/exacerbates the shedding of sandstone laminations.

Perhaps one could argue that saltwater permeates the bedding planes, evaporates leaving salt precipitate, the buildup of which results in mechanical weathering??? That is, the pressure of the accumulating salt precipitate is enough to overcome the weakly cemented sandstone laminations abd they simply flake off. ?? ¿¿ ??

 

[wayner]

I have individually cut flagstone pieces and I don't think they have staining from salt. I would not get them again as they raise up due to frost heaves over the winter and become unequal and have to be releveled every few years. And several of them have major cracks as the holes that were drilled for my pool cover anchors created weak spots and the stress of the cover weight was enough to have them crack.

 

[wayner]

I’m curious what the scientific rationale would be to support the notion that saltwater increases/exacerbates the shedding of sandstone laminations.

Perhaps one could argue that saltwater permeates the bedding planes, evaporates leaving salt precipitate, the buildup of which results in mechanical weathering??? That is, the pressure of the accumulating salt precipitate is enough to overcome the weakly cemented sandstone laminations abd they simply flake off. ?? ¿¿ ??

That's possible but I would think that in areas that get freezing that water that turns to ice in between the laminations is way worse. You appear to be from Texas but apparently Texas is now getting the odd deep freeze.

 

[Newdude]

I’m curious what the scientific rationale would be to support the notion that saltwater increases/exacerbates the shedding of sandstone laminations.

So it's well documented here that most 'chlorone pools' will end up between 5% and 7.5% of seawater salinity. The 'salt pool' is 10%

The entire argument against salt because of damage hinges on 5% or less of seawater salinity.

Several members were *at* salt level, or above when they went to switch.

 

[Katygreys]

Yes wayner, the process I was describing would be similar to ice wedging.

Newdude I hear you. I realize we are talking small differences in salt vs non salt pools. Just exploring here

The pool guy I fired when I switched to tfp is cool. Actually like him a lot. I had him come out to give me a quote on installing SWG. The only thing he cautioned me against was the “flagstone issue”.

Btw, he quoted me 350 to install it, if I buy the swg and flow sensor. I would need some re-routing of the plumbing.

 

[Oly]

Several members were *at* salt level, or above when they went to switch.

And one ... me... was above at 4200ppm .....
Had to drain off 18" and refill before I could start up.
Test before you dose.

 

[Newdude]

Btw, he quoted me 350 to install it, if I buy the swg and flow sensor. I would need some re-touting of the plumbing.

You trust him and that's a good price. I'd jump on it when you're ready.

 

[Newdude]

I realize we are talking small differences in salt vs non salt pools. Just exploring here

Please. Explore away. I was daring science to prove that the level where salt starts to cause damage was between the #s I mentioned.

It is not science saying salt pools will cause problems. It's Texas PBs / pool stores and word of mouth from all their clients.

What science will say, is that poor quality materials have problems when exposed to moisture.

 

[TexEdmond]

We have some flagstone around the pool, should I be worried about staining?

Nope! Just be sure not to spill undiluted chlorine or acid on it. Immediately dilute spills by scooping plenty of pool water out.

 

[TexEdmond]

I realize we are talking small differences in salt vs non salt pools.

Also consider that some folks with manually chlorinated pools will raise salt levels up to improve the feel of the water. Most everyone says something like, "when I get out of a chlorine pool, I feel like I have to take a shower. When I get out of a saltwater pool I feel like I just got out of the shower."

The chemistry of chlorinating the pool is identical whether it's a jug of bleach or a salt cell chlorinator. It's the salt that softens the water and makes it feel luxurious.

 

[PoolStored]

I started clean last year with new water. LC only. After 1 year my salt was 1100ppm. After a couple years, it could be 3-5000ppm A chlorine pool is a salt pool. Every gallon adds, I think 2.1 or 2.2 lbs of salt.