ozone generator and UV light questions

[markpg101]

Good day, I am a new pool owner. I had my contractor install an ozone generator and uv light but after a few weeks, my pool has been cloudy and has been turning green. My ph levels were a little high so we put some dry acid. it helped with the cloudiness but after a few days, algae started growing. Note that our pool is just 3 weeks old. It made me question if my ozone and UV light is working properly or if it has the right connection by my pool contractor. I researched more and found out that my ozone generator doesn't have any ozone injection manifold which I assume controls the ozone gas to the pool which is included in the items manual but my contractor said that there was no injection manifold included. I really have doubts on how my contractor has connected my ozone and uv light. I will post a photo of my pools connection here. I would appreciate it if someone can help me with this so i can educate my pool contractor. Thank you

 

[Newdude]

Hey Mark and Welcome !!!!

Your contracter may have something missing or backwards, but either way, those systems do nothing to sanitze the pool. They do ok on the water that is inside the unit, but the 99.9999% of the pool that isnt inside the unit is in the pool festering, possibly for days before it finds its way into the Ozone/UV.

They also can't be tested to see if they are working.

You need to fully sanitize the pool with chlorine per the FC/CYA Levels. The UV system will burn up some of that chlorine, so it actually hurts you if the pool is outdoors and you already get UV-C from the sun.

 

[JoyfulNoise]

Two things -

1. If you are not using chlorine in your pool for sanitizing and disinfection, then you will never get rid of algae. Period. All swimming pools in the USA must use some form of approved sanitizer - chlorine, bromine, or biguanide. Not sure how it is in the Phillipines, but, regardless of where you live, chlorine is a must.

2. It looks like your pool builder installed injectors both before and after the filter. Not sure why he did that but it could cause problems if Venturi pulls water from the pump side instead of ozone. I would follow the instruction manual instead . Also, if the installer installed the check valve backwards then that would cause no ozone as well.

 

[markpg101]

Hey Mark and Welcome !!!!

Your contracter may have something missing or backwards, but either way, those systems do nothing to sanitze the pool. They do ok on the water that is inside the unit, but the 99.9999% of the pool that isnt inside the unit is in the pool festering, possibly for days before it finds its way into the Ozone/UV.

They also can't be tested to see if they are working.

You need to fully sanitize the pool with chlorine per the FC/CYA Levels. The UV system will burn up some of that chlorine, so it actually hurts you if the pool is outdoors and you already get UV-C from the sun.

Thank you very much for the much needed info. I will take a look at this. You have been very helpful

 

[markpg101]

Two things -

1. If you are not using chlorine in your pool for sanitizing and disinfection, then you will never get rid of algae. Period. All swimming pools in the USA must use some form of approved sanitizer - chlorine, bromine, or biguanide. Not sure how it is in the Phillipines, but, regardless of where you live, chlorine is a must.

2. It looks like your pool builder installed injectors both before and after the filter. Not sure why he did that but it could cause problems if Venturi pulls water from the pump side instead of ozone. I would follow the instruction manual instead . Also, if the installer installed the check valve backwards then that would cause no ozone as well.

Thank you very much for the tips. I really need all the tips i can get to understand how a pool works. I really don't understand my pool builder either. He insists that this is the right way but by looking at the manual, this is not the way to do it as you pointed out. I tried reaching out to the manufacturer (waterco) but they don't bother answering me. Its really frustrating. Again, I really appreciate you taking time to explain.

 

[markpg101]

Two things -

1. If you are not using chlorine in your pool for sanitizing and disinfection, then you will never get rid of algae. Period. All swimming pools in the USA must use some form of approved sanitizer - chlorine, bromine, or biguanide. Not sure how it is in the Phillipines, but, regardless of where you live, chlorine is a must.

2. It looks like your pool builder installed injectors both before and after the filter. Not sure why he did that but it could cause problems if Venturi pulls water from the pump side instead of ozone. I would follow the instruction manual instead . Also, if the installer installed the check valve backwards then that would cause no ozone as well.

One more question, why do you think my contractor connected the ozone before and after the filter? My contractor never really gives me a straight answer regarding this. Also, if you look at my uv light connection, there is a pipe that is open from the filter that partly goes to the uv light and partly goes straight to the pool. Do you think this is the right way to do it? or should i close the valve so 100% of the water from the filter will pass the uv light? I'm sorry to take up your time. Thank you

 

[JoyfulNoise]

Referring to your setup -




In the current configuration with all three valves (1,2,3) in the OPEN position, the vast majority of the water flow will be along the primary path (green arrow) and very little water will flow through your UV lamp. If you fully close Valve #1, then all of the water will flow from your sand filter through the UV lamp. The contractor really didn’t do a good job plumbing the bypass line to the the UV source. In reality it can be greatly simplified - valves #1 and #2 can be replaced by a single 3-way valve and valve #3 could be replaced by a check valve. The new 3-way valve would then adjust how much water you want to flow to the UV lamp versus straight back to the pool.

As for the ozone generator, it should be plumbed according to the instructions. I don’t believe it will work properly the way it is set up now.

 

[YippeeSkippy]

What did your builder plan as far as sanitizing the entire pool? How did they plan for avoiding algae?

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.troublefreepool.com

Maddie

 

[markpg101]

Referring to your setup -

View attachment 397803


In the current configuration with all three valves (1,2,3) in the OPEN position, the vast majority of the water flow will be along the primary path (green arrow) and very little water will flow through your UV lamp. If you fully close Valve #1, then all of the water will flow from your sand filter through the UV lamp. The contractor really didn’t do a good job plumbing the bypass line to the the UV source. In reality it can be greatly simplified - valves #1 and #2 can be replaced by a single 3-way valve and valve #3 could be replaced by a check valve. The new 3-way valve would then adjust how much water you want to flow to the UV lamp versus straight back to the pool.

As for the ozone generator, it should be plumbed according to the instructions. I don’t believe it will work properly the way it is set up now.

Thank you again. I really appreciate the feeback. You have been so helpful

 

[markpg101]

Referring to your setup -

View attachment 397803


In the current configuration with all three valves (1,2,3) in the OPEN position, the vast majority of the water flow will be along the primary path (green arrow) and very little water will flow through your UV lamp. If you fully close Valve #1, then all of the water will flow from your sand filter through the UV lamp. The contractor really didn’t do a good job plumbing the bypass line to the the UV source. In reality it can be greatly simplified - valves #1 and #2 can be replaced by a single 3-way valve and valve #3 could be replaced by a check valve. The new 3-way valve would then adjust how much water you want to flow to the UV lamp versus straight back to the pool.

As for the ozone generator, it should be plumbed according to the instructions. I don’t believe it will work properly the way it is set up now.

In your opinion, is it better for 100% of the water coming from the filter to pass thru the uv lamp?

 

[JoyfulNoise]

In your opinion, is it better for 100% of the water coming from the filter to pass thru the uv lamp?

No. At high water velocities the UV will be less effective. The effectiveness of UV sterilization is based on fluence which is, in part, the power output of the lamp at a specific wavelength (UV-C for pathogens) multiplied by the contact time. If the water flies through the UV cell at high velocity then there isn’t enough fluence applied to effectively kill pathogen.

The downside of an in-line UV source is that it requires a by-pass flow setup like you have and a very slow flow rate through the UV cell. That means the pump has to run many, many turn overs of the pool water to even come close to being effective. If one assumes perfect hydraulic efficiency, meaning your pool water is perfectly mixed and homogenous when it is being pumped (a foolish assumption at best), then it takes 7 turn overs of the pool volume to achieve a roughly 95% contact. Seven turn overs per day of most pools would require pumps to run 24/7 at high speeds. So, at then end of the day, UV sterilization is highly ineffective at pathogen control.

 

[1poolman1]

I've been using a UV/ozone system for several years. You must have some chlorine in the water or you will get algae. I am just able to get by with much less than I used to use. There is a lot of controversy surrounding these systems, but I have had no issues with mine nor any of the others I have installed.

 

[YippeeSkippy]

LOL Matt.... So what he just said @markpg101 , in not as few words, is that the UV/Ozone stuff is worthless and you should not waste your money.

Maddie

 

[Newdude]

You must have some chlorine in the water or you will get algae

You must have *all* the chlorine in the water or bacteria, viruses and pathogens will not be sanitized.

Algae is the harmless canary in the coal mine. The danger is swimmer to swimmer transmission of bodily fluids / germs / fecal matter / etc. All of which will make it to the fellow swimmer long before it ever gets to the UV / Ozone unit.

The industry and average owner is fixated on controlling the unsightly algae. Control/kill the stuff that will harm you, and the algae can't grow either.

 

[1poolman1]

As I said, controversy. Of course "all" the chlorine is in the water. UV, ozone, UV/ozone systems are not meant to replace the sanitizer in the water. They do, though, improve the water quality and sanitizing along with it. They are a secondary system and are now being required on many commercial pools. For example, it takes 20ppm of chlorine 12.75 hours to inactivate cryptosporidium, a very common contaminate in pools. (National Swimming Pool Foundation’s Pool & Spa Operator Handbook). UV/ozone systems have a 99.9% kill rate on the first pass. (https://www.poolspanews.com/facilities/maintenance/shedding-light-on-uv-and-ozone_o)

 

[YippeeSkippy]

Poolman, don't you think California gets enough UV free of charge from the sun? And there is no way an Ozone machine can be tested for effectiveness, so why waste the greenbacks? AND the Ozone light will burn away your wanted chlorine so you lower your FC unnecessarily and possibly invite algae in.

 

[wireform]

Just thought about this one, I have a pool that the uv lamp was burned out last season from the get go. Ordered the new one but never installed. Wouldn't you know there was no difference in water quality as this is a SWCG pool.

 

[Newdude]

UV/ozone systems are not meant to replace the sanitizer in the water.

But the manufacturers sadly don't agree with us.

They are a secondary system and are now being required on many commercial pools

Many municipalities don't allow CYA at all and only an incredibly low level of FC. In many cases it is less than their own tap water. So the ozone and UV are needed as sanitizers. But as you know, the commercial units are far larger and equally as more expensive. The rinky dink residential units don't equate to much besides a light bulb and blowing air through a straw.

For example, it takes 20ppm of chlorine 12.75 hours to inactivate cryptosporidium, a very common contaminate in pools. (National Swimming Pool Foundation’s Pool & Spa Operator Handbook). UV/ozone systems have a 99.9% kill rate on the first pass.

Without ever being able to 'turnover' the water due to mixing, it may not ever make it through the unit. Besides. Crypto is fairly rare. The rotovirus on the other hand is running rampant right now. Swimming around with that for a few hours in an underchloronated pool won't end well for far more people.

 

[markpg101]

No. At high water velocities the UV will be less effective. The effectiveness of UV sterilization is based on fluence which is, in part, the power output of the lamp at a specific wavelength (UV-C for pathogens) multiplied by the contact time. If the water flies through the UV cell at high velocity then there isn’t enough fluence applied to effectively kill pathogen.

The downside of an in-line UV source is that it requires a by-pass flow setup like you have and a very slow flow rate through the UV cell. That means the pump has to run many, many turn overs of the pool water to even come close to being effective. If one assumes perfect hydraulic efficiency, meaning your pool water is perfectly mixed and homogenous when it is being pumped (a foolish assumption at best), then it takes 7 turn overs of the pool volume to achieve a roughly 95% contact. Seven turn overs per day of most pools would require pumps to run 24/7 at high speeds. So, at then end of the day, UV sterilization is highly ineffective at pathogen control.

Thank you again. It's clear to me now. I really appreciate it.

 

[Donldson]

They do, though, improve the water quality and sanitizing along with it.

That blanket statement is unsupported.

The reason such systems are now being required for commercial pools is simple: people with a financial interest like yourself convince lawmakers they are necessary. Nothing new, every industry does what they can to push financially beneficial laws.

Not that these systems don't have their place in the commercial field. Massive bather loads do offer situations where supplemental oxidation and/or sanitation are useful and good quality units can benefit the system. In a low bather load private pool with the low quality equipment that's available, it's a complete waste. A great residual income source for the sellers and a placebo for the owners.