UV/Ozone System vs SWG - which is truly better?

[jeremyf0923]

Hello all,

New member and first post. Thanks in advance for your guidance/advice. Close to signing a contract for a small (9x20) gunite pool. I know that is an odd size, but unfortunately biggest I can fit between sanitary line and a storm line easements. That said, the PB I'm mostly likely to go with is adamant about using a UV/Ozone sanitation system - he says that "it is a much higher sanitizer than a salt system, helping keep the pool pH neutral, and providing soft water. We have been using the system for about 12 years now. Soon, every pool across the country will have this installed. All competitive swim pools NCAA/Olympics are already mandated to have this system in play." He also said he hasn't done a dedicated salt system in about 10 years and raised concern about how corrosive the salt is to gunite pools. Really struggling because everything I read online says go with a SWG system. In fact, very little information online about these UV/Ozone systems. I found some old posts on this forum that say the same - SWG all day long over UV/Ozone. Having a hard time understanding why my PB is taking such a strong position, which seems to be contradictory to virtually everyone else's opinion. He did agree to put in a SWG system if that is what I prefer. Am I missing something? Is he just trying to sell me on something because he is incentivized to do so?

Would welcome your thoughts and opinions.

Thanks!

Jeremy

 

[PoolStored]

Having a hard time understanding why my PB is taking such a strong position, which seems to be contradictory to virtually everyone else's opinion.

$$$

Put in the SWG and don't look back.

UV Systems - Further Reading

www.troublefreepool.com

Ozone Systems - Further Reading

www.troublefreepool.com

 

[Newdude]

Am I missing something?

Ozone and UV don't add residual sanitizer so you still need to add the full amount that the sun burns off, rain or shine. At that point, the Ozone/UV don't serve a purpose in an outdoor residential pool. They are sanitizing already sanitary water that passes through them. (And only that minute fraction of the pool volume. Any swimmers are on their own).

The SWG adds residual sanitizer to cover that chore instead of adding liquid chlorine every day.

Is he just trying to sell me on something because he is incentivized to do so?

That, and likely not understanding basic water chemistry.

Neither Ozone or UV provides soft water, for example. He must have gone elbow deep pulling that one out if his rear.

 

[TinFoilHat]

What a crock of @#$% from that guy. It's all about the money, clearly. You might want to find a more scrupulous pool builder.

 

[Newdude]

You might want to find a more scrupulous pool builder.

They will all be trained in the same industry manner which favors profitability over science. They like don't even know the big players dismissed said science.

 

[reggiehammond]

If you'd like to stick with the PB, I'd just consider telling him you're going to use liquid chlorine and you don't want to spend any money on UV/Ozone/Puck chlorinators. Once he's gone, you can add a SWCG easily and be up and running without wasting any money on unneeded equipment.

 

[proavia]

Your pool builder of choice will make certain recommendations based on what they "think" they know or what offers them the best profit. At the end of the day, it's really YOUR decision and YOUR money.

UV isn't needed in an outdoor pool as that big bright orange ball in the sky provides more than enough UV already.
Ozone is not a primary sanitizer - chlorine is. And ozone will eat a bit of chlorine.

If you decide to go SWG, be sure to spec one at least 2x the pool volume.

 

[Lake Placid]

What did he tell you he was going to use as the primary sanitizer? Both UV and Ozone are considered supplemental because they leave no residual. Consequently he will still have to provide a system to sanitize the pool. So what's his plan?

 

[jeremyf0923]

What did he tell you he was going to use as the primary sanitizer? Both UV and Ozone are considered supplemental because they leave no residual. Consequently he will still have to provide a system to sanitize the pool. So what's his plan?

It is listed as this on the pool build quote: OxiPro Ozone & UV combo system w/ in-line chlorinator & Smart Guard System

 

[Newdude]

w/ in-line chlorinator

That's a puck feeder and pucks are stabilized with CYA. Each puck raises your CYA and for every 10, your FC needs to be raised proportionately to sanitize at the same level. All lines on this chart are equal for sanitizing.



The industry ignores the direct FC/CYA relationship that was discovered in the 70s. Whether they do so from ignorance, or because green pools are profitable it doesn't end well for the pool owner.

FC/CYA Levels

 

[Lake Placid]

That said, the PB I'm mostly likely to go with is adamant about using a UV/Ozone sanitation system - he says that "it is a much higher sanitizer than a salt system, helping keep the pool pH neutral, and providing soft water.

He is full of baloney. Trichlor has a PH of 2.8 which is very acidic. It will drive the PH of the water down, and will take TA with it in the process. So it is most definitely not neutral. He is also wanting to put in an in-line chlorinator which is old, antiquated, and unreliable at best technology to provide chlorine. Tell him you want a SWG and be done with it.