Salt System newbie

[CarlD]

No one is born knowing this stuff, so no question is a dumb one, except the one unasked!

Or the one repeatedly asked with hopes of getting a different answer!

[BigTallGuy]

Oh yeah, I have made millions asking dumb questions. The problem is, I unfortunately ask them too late and it has cost me those same millions. So I have resigned myself to know my place in life as the lowest level of the food chain, dwelling down in the pond scum and looking up at catfish bellys every morning just to see the sunshine. So if my questions become too stooopid, a shoe to the back of the head usually works. Hey thanks for listening to me. It is truly a pleasure to be here.

Dumb question number three, are those small hand held Salt Level checkers Worth their (oh no here it comes) SALT? (bad I know). I see these things on the internet for $12-$15 all the way up to $85-$100 USD. All I know is, every pool store I go to gives me a different salt reading. I am bouncing the idea around in my over impulsive feeble brain to buy my own. But logic tells me that the "LOW SALT" light is off on the unit so save yer Money.

What say you guys?

[BigTallGuy]

Progressing on in my quest to become the fastest pool expert on the planet, my CYA level is reported to be between 40 and 50. The Pool Store "experts" want me to go to 60-80 because of the salt system. They probably want to sell me more CYA.

Everything I am reading says any CYA level above 50 is waste. From experience, I know that when my CYA levels were "elevated" up over 100, I had constant complaints of eyes burning. So I am extremely leery of adding any more CYA.

Dumb question number 4 is (drum rolllllllllllll):

What do you recommend for a CYA level for a vinyl lined AG salt system pool, and Why?

(Is that two questions)?

[AnnaK]

It's my understanding that the CYA level in SWCG systems is best kept at 60-70 ppm. The 'why' is something Chem Geek will need to address.

[chem geek]

If you find that the pH tends to rise over time and if your pool is exposed to direct sunlight, then having the CYA in the 60-80 range, especially 70-80 ppm, has the chlorine protected more from breakdown in sunlight. Even proportionately raising the FC level to 4 ppm minimum with 80 ppm (for an SWG pool), there is less absolute chlorine loss.

The lower chlorine loss lets you turn down the SWG on-time and that reduces the rate of pH rise (from whatever the cause -- could be more outgassing of either carbon dioxide through aeration or of undissolved chlorine gas).

Adding 50 ppm Borates can also help reduce the rate of pH rise through two effects -- it acts as a pH buffer and it is a mild algaecide so may further reduce daily chlorine usage. It's also insurance since at the higher CYA level you want to make sure you don't have the FC drop below the minimum since fighting an algae bloom takes a lot more chlorine (higher FC level) when the CYA level is higher.

As for eyes burning at 100 ppm CYA, that probably wasn't a direct result of the CYA but the FC probably wasn't high enough (i.e. was below 5 ppm) and that meant that the active chlorine level could have been so low as to have more chloramines in the pool and those can be irritating to the eyes. Either that or the pH may have been off (too high or low). If you find any problem at 80 ppm CYA with 4 ppm FC, try increasing the FC target to 6 ppm, but I doubt you'll need to do that since there are many, many people with SWG pools that mostly operate with 4 ppm FC and 80 ppm CYA without any issues.

[BigTallGuy]

I have only had my SWCG for two weeks and the "official" swimming season hasn't started yet. I am watching my chemicals very closely including the pH levels. My 24' round AG pool takes direct sunlight for the majority of the day and I still consider myself to be in the Start-up mode.

Here are my Thoughts. I am not trying to be arguementative, but I am always open for a nice discussion and maybe I'll learn something along the way.

My overall philosophy is to keep all chemicals to a minimum. I have added seven 40lb bags of salt and I probably need to add another half to a full bag. I am at 3300 PPM of salt and should be at 3500 PPM according to the manual but the low salt light is out. I am reluctant to add more salt as the water already has a slight salty taste to it even though the internet says most humans cannot taste salt below 3500 PPM.

I am at approximately 40 CYA and really don't understand why a Salt system requires more that a traditional Chlorine pool. For now, my SWCG runs 8 hours a day regardless, and if my current CYA levels keep a minimum amount of chlorine in the pool until the pump kicks on and adds more chlorine, then I want to believe I'm good. But hey, they don't call me the BTDG for nothing.

As far as my previous bad experience, I can only tell you that I had my water checked repeatedly and by multiple pool stores and the response was that my water was "Picture Perfect" except for the CYA value and I still had burning eye complaints. I did drain 25 inches of water from the pool, leaving 15-16 inches of water remaining to eliminate the high CYA and still ended up with a reading of 100-110 AFTER refilling.

[chem geek]

As I wrote, the reason for the higher CYA for an SWG pool is to reduce the rate of pH rise by reducing the rate of chlorine consumption thereby letting you lower your SWG on-time.

If you are not experiencing a pH rise that you find intolerable, adding a lot of acid every week, then you can certainly leave your CYA at 50 ppm and keep your FC at least at 2.5 ppm if not 3 ppm minimum. That's perfectly fine and is totally up to you. I was only explaining why a higher CYA is usually done in most SWG pools -- it is a legitimate reason that works well in most cases.

Yours, however, is the only case of stinging eyes from tens of thousands of pool owners that is not attributable to either chloramines (usually from low FC relative to CYA) or an out-of-whack pH. There are many pools with very high CYA levels -- even over 200 ppm in pools using only stabilized chlorine -- and stinging eyes aren't a direct result, though indirectly if the FC is low and Combined Chlorine (CC) is present then stinging eyes are reported. Your experience is very real and there is no question about that -- it may be the CYA or it might not be. Chemical sensitivity is a unique experience and perhaps you have a sensitivity to this chemical.

Also keep in mind that pool store tests are very often wrong. I would only trust your own testing. Though the pool stores usually don't get the pH that wrong (though sometimes they do), they very often get the CYA test very, very wrong. It could have been far higher than 100 and you could have very likely had high chloramine levels as a result. This should not happen if you maintain a higher FC with the higher CYA -- i.e. 4 ppm FC with 80 ppm CYA, but again you do not have to do this -- it's completely up to you.