Saline acidity

[ajw22]

Having the details of the body of water you are maintaining would help in answering your questions. Please create your signature with details of your spa.

Is it outdoors?

Is it covered when not in use?

 

[mrwoo]

Ahh, okay I did that correctly I think.

It's covered most of the time and is outdoors. As my sig now says, it's under a rigid dual layer polycarbonate roof on NE side of house, so even if the cover is off it's minimal UV exposure.

 

[ajw22]

So here are my questions. On the wiki here is suggests 60ppm CYA for swg. But I don't need it for UV at all, is this going to be critical for the chlorine generation? I do understand that the CYA is a buffer and sort of "reservoir" for FC.

CYA has no effect on chlorine generation. CYA does buffer chlorine harshness. I would run your CYA at 20-30.

Is the type of salt going to limit FC production?

No, Salt is salt.

My water is 2 weeks old and I've shocked it once as noted above, tested it many times each day as I'm learning all this. I cannot imagine the saltron is not working as it's bubbling up like it should. I've wondered if I have some growth that's too much for the swg but when I was adding dichlor to get the CYA up it was the same amount every day pretty much.

Are there any specs anywhere of what your Salton SWG chlorine output should be? 8 hour runtime may not be enough. Why not run it for 24 hours or more and see what FC you get?

 

[mrwoo]

When I get home I will check what the specs are. I believe it's rated in grams per hour or grams in a 24-hour period. I was running it in shorter increments based on my schedule because I was trying to discern what it would do in a given time span. You're probably correct though, I should just run it for 24 hours and see if it can keep up with my to our daily use.

 

[Jimrahbe]

Woo,

Just for reference, my spa is only 200 gallons and my SWCG runs for 5 or 6 hours a night...

Jim R.

 

[mrwoo]

Thanks for the replies.
The unit says it outputs 1.1oz of FC per day or 32 grams.
That's 32000 ppm per day, per liter? 425 gallon=1608 liter, so 32000 ppm / 1608 L = 20 approx.
That should mean the unit generates 20 ppm for 425gallon tub in 24 hours.

Or 32 g / 24 hr = 1.33 g/hr of FC
1.33 g/hr x 1000 = 1330 mg/hr (or ppm/hr)
Edited for correction:
Therefore 1330 ppm per hr / 1680 liter tub = 0.82 ppm FC per hour output for that volume of water?

I have no problem running it longer at all I just wasn't anticipating it. And maybe my math is all wrong.

Appreciate the help for sure.

 

[Mdragger88]

I also have a saltron mini- i have it set to 1hr & plugged into a timer that cuts off/on 4x’s a day in the winter - so my 4 hrs is spaced out since i use my tub multiple times a day. In the summer i just do twice a day- less use. It requires less salt ppm than my pool & my tub is roto molded so as long as you address the real corrosion creators (ph, ch, csi) you’ll be fine- I rarely need to add chlorine- only do so if i have a large bather load. Also I don’t remove my cell unless the kids get in- what can i say, i guess i’m a rebel lol? i have had this set up for a little over a yr- the life of my 200 gal Home Depot hot tub.

 

[mrwoo]

Thanks for the reply. I thought about a timer actually. Turns out it's been more confusing that I thought it would be. I am currently running it for 16 hours in a 425 gallon tub. I've got a lot of questions I'm going to have to start another thread for. I guess if I didn't test so much I would be blissfully ignorant lol. Thanks again for sharing.

 

[Mdragger88]

Thanks for the reply. I thought about a timer actually. Turns out it's been more confusing that I thought it would be. I am currently running it for 16 hours in a 425 gallon tub. I've got a lot of questions I'm going to have to start another thread for. I guess if I didn't test so much I would be blissfully ignorant lol. Thanks again for sharing.

After reading this forum I am very hesitant to get in anyone else’s water- tfp has made me a water snob lol? I have come to realize most owners have no clue what’s going on in there pool or spa & don’t care to know! They can swim in it but i ain’t gonna? You’ll sort it out & get a “feel” for the maintenance of it & be more comfortable in time. The important thing is that u are asking all the right ?’s & everyone here will help u along the way! Happy Hot tubbing!

 

[jseyfert3]

so as long as you address the real corrosion creators (ph, ch, csi)

pH is the only factor for corrosion to metal. CSI is the only item of concern for corrosion to stone/tile/gunite, or buildup of precipitate. All the other factors either feed into the adjustments for pH and CSI or have some other reason for use, but don't directly affect corrosion.|

To the OP: I think it's been covered by now, or you've been convinced, but keep in mind that typically a non-SWCG pool or spa will end up with more salt than one with a SWCG ! This is because adding chlorine adds salt, but with a SWCG the salt is recycled into fresh chlorine without increasing the salt levels in the pool/spa.

EDIT: I just did a quick calc, you most likely won't hit more salt without a SWCG if you change the water every 3-4 months as is typical, but you would probably end up with more salt in a pool since those don't usually have water changes.

 

[mrwoo]

Hmm. Is there any information as to how many ppm of salts bleach or muriatic acid adds? I realize it's not salt as in sodium chloride and that all chemicals add salt and all contribute to the whole. It would be pretty easy to log the amounts and have an idea of where you are exactly. Further, does the salinity test work for total salts or sodium chloride only? I was actually thinking about using my inline water meter when topping off. If I did so I could easily know how it would dilute the tub and could have a rough guess of where the chemistry stands.

 

[ajw22]

Hmm. Is there any information as to how many ppm of salts bleach or muriatic acid adds?

Bleach/Liquid chlorine adds 1.65 ppm of salt for every 1 ppm of chlorine.

MA does not contain salt.

 

[jseyfert3]

Hmm. Is there any information as to how many ppm of salts bleach or muriatic acid adds? I realize it's not salt as in sodium chloride and that all chemicals add salt and all contribute to the whole. It would be pretty easy to log the amounts and have an idea of where you are exactly. Further, does the salinity test work for total salts or sodium chloride only? I was actually thinking about using my inline water meter when topping off. If I did so I could easily know how it would dilute the tub and could have a rough guess of where the chemistry stands.

PoolMath, Effects of adding chemicals section. Either desktop or mobile versions have this.

Actually for liquid chlorine it is salt as in sodium chloride. Liquid chlorine is sodium hypochlorite, or NaOCl. This disassociates and there's some secondary reactions that produce HOCl, your primary sanitizer, but at the end all the liquid chlorine you add eventually becomes Na+ and Cl-, exactly the same as if you dumped table salt in your pool. Other types of chlorine replace the sodium ion with something else, but the chloride ion is always there. See Chlorine turns into salt?

 

[ant 83]

I shocked it up to 24ppm FC with bleach

This will immediately oxidize your CYA to negligible amounts. You can test to confirm.

With zero CYA Free Chlorine in the very low single digits is still very strong, and any higher amounts of Chlorine tends to immediately evaporate. Evaporate more quickly the higher the temp.

 

[jseyfert3]

This will immediately oxidize your CYA to negligible amounts. You can test to confirm.

That seems a little unlikely. If this was the case, TFP would probably be having people super chlorinate to remove CYA instead of doing often tricky and expensive water changes to lower CYA.

Chem Geek mentions in the following thread that FC can neutralize CYA in a matter of hours...if the pH is 9-10 and the FC/CYA ratio is something like 3-4, neither of which is the case with the OP. Degradation of Cyanuric Acid (CYA)

That said, gradual reduction of CYA is expected, with monthly losses in a typical spa of 5-10 ppm probably not out of the ordinary, so if the OP has not checked CYA in a while they certainly should do that.

 

[mrwoo]

I had not seen yet that FC could lower CYA. I'll have to test it and see I guess although the water is only 3-4 weeks old now.

 

[ant 83]

That seems a little unlikely. If this was the case, TFP would probably be having people super chlorinate to remove CYA instead of doing often tricky and expensive water changes to lower CYA.

You know, Ive thought about this, and the best answer I can come up with, is that there are other benefits by changing water as a 'best practice' recommendation. Removing salt is a big one. But also, everything else that accumulates in pools.

Also temperature plays a roll, making it less useful for pools. You have to account for sunlight burning off your added bleach.

All's I'm saying is that people test.

monthly losses in a typical spa of 5-10 ppm probably not out of the ordinary,

This is definitely out of the ordinary for me, and has been for years now. Always more. Way more. 300% more.

Please stop saying 5-10ppm per month, and say you should test every month.

Also, from YOUR link:

So, assuming a CYA loss rate of around 0.4 ppm/day in our pools this comes to 12 ppm per month which is clearly enough to be noticeable as the months pass during a swim season. If one shocks the pool, then the rate of loss could be about 2-3 times faster.

And

every 10F increase in temperature results in roughly doubling the rate of degradation.

 

[jseyfert3]

I'm not saying that temp and FC levels don't increase the rate of CYA degredation. Clearly, they both do. What I was saying is that having it at the level he did for 24 hours will not removal ALL the CYA, like you said it would. It will obviously remove SOME.

I did say the OP should test the CYA, did I not?

 

[ant 83]

you did.

I'll stop with this. I feel like we're getting off topic.

cheers.

 

[mrwoo]

I calculated 44ppm CYA based on my dichlor additions. That was a few weeks ago. Tested last night and result was just above 40. Tf-100 test kit.

My water has begun to have a slight odor to it on my skin, predominantly wear just a little bit of foam happens, like on my arm where I brush it away. If I start out with 6 PPM of FC, an end around 1, but do not smell chlorine particularly, would it be safe to assume that perhaps I have some oils etc that just need to be shocked?