UV Sterilizers, pumps, filters and Pressure side Pressure: Too High

Yurij

Active member
Aug 19, 2020
25
Warren, NJ
I installed a DEl UVC-50 this year and ended up with very high pressure. Looks like the Del has a lot of 90 degree bends and I made the mistake of installing in with a 2" to 1.5" reducer fitting. Next year I will make sure all pipes coming out of the pump are 2" right through to the filter and into my heater. Unfortunately the heater only accepts a 1.5" connection in and out. I have check valves installed both on the intake and pressure side of the system. I plan on installing another Del UVC-50 and split the flow out of the filter between the two UV sanitizers. Hopefully I will be able to reduce the head pressure and gain more efficiency out of my pump. Any thoughts or suggestions about how I can optimize flow rate through my system? I have a spare Pro-Grid-7200 and considering running both filters (Perlite media) in parallel to gain more efficiency out of my pump. I'm an Engineer and like to play! Lol! :) Comments are welcome. See attached picture.
 

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Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,855
Central California
Comments welcome? OK, you asked for it. Want to improve flow: get rid of the first UV unit and don't buy the second one. UV sterilizers alone do not provide adequate protection for human swimmers. You'll also need chlorine in your pool. Chlorine can do everything UV can, only better, and then provide other protections UV can't. You don't need both, so why have equipment maintenance issues and expenses you don't need. Invest in SWG, not UV. I can offer the long-winded explanation if I haven't already lost you...
 

Yurij

Active member
Aug 19, 2020
25
Warren, NJ
Comments welcome? OK, you asked for it. Want to improve flow: get rid of the first UV unit and don't buy the second one. UV sterilizers alone do not provide adequate protection for human swimmers. You'll also need chlorine in your pool. Chlorine can do everything UV can, only better, and then provide other protections UV can't. You don't need both, so why have equipment maintenance issues and expenses you don't need. Invest in SWG, not UV. I can offer the long-winded explanation if I haven't already lost you...
I hear you and appreciate the comment. I do use chlorine that I keep at 3ppm using the Poolfrog XL. I also liquid shock once a week. I have the heater with a Cupro nickel heat exchanger and want to avoid corrosion issues installing a SWG system. (Or excessive chlorine for that matter) With all due respect, I understand UV sanitizers or any system for that matter requires minimal chlorine. The UV sanitizer made a huge difference with water clarity and results can't be disputed. I think the pressure issue can be resolved and worth the benefits of having zero algae problems with the pool. At tis level I understand it can be a matter of preference if you consider the pros and cons. I researched before purchasing. This is a straight forward Engineering flow problem and will do the calculations before moving forward. You can erase paper and good practice to calculate before you invest. This one caught me by surprise. By the way, I would not recommend using a cartridge filter for any reason. (Mainly the maintenance issues required for cleaning) After 20 years of owning a pool, DE, using perlite, is the only filter media I would consider. Thanks for the comment.
 
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Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,855
Central California
Sorry, didn't mean to sidetrack your subject. If you've got chlorine in the water, then you're good-to-go. Good luck with the plumbing. Others here can help...
 
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Yurij

Active member
Aug 19, 2020
25
Warren, NJ
Sorry, didn't mean to sidetrack your subject. If you've got chlorine in the water, then you're good-to-go. Good luck with the plumbing. Others here can help...
No worries. I appreciate the advice! There are many ways to achieve crystal clear water and Chlorine is a sure proven solution. I just want to minimize the amount of chlorine that goes into the pool. I avoided an ozonator because of the risks to my heat exchanger. Be well and I enjoyed the chat.
 
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Yurij

Active member
Aug 19, 2020
25
Warren, NJ
The Frog adds metals -- so be ware of that.

The UV device does not reduce the need for a proper level of FC based on your CYA. In fact, the UV device consumes FC.
Last year I had to replace my heat exchanger due to a small leak. Although the frog puts out minimal chlorine I was unaware it puts out excessive metals. So you suggest eliminating the frog due to risks to my heater? I'm Curious.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,000
Laughlin, NV
Not a risk to the heater, risk to staining the pool surfaces and turning blonde hair green. Unless you are using trichlor too, that is a risk to your heater.

What is your pool surface? Can you add that plus the volume to your signature?
 

Yurij

Active member
Aug 19, 2020
25
Warren, NJ
UV systems add no benefit to outdoor pools. They get plenty of UV.

As for head loss, that is entirely due to the UV unit. 1.5" to 2" bushing has very little head loss so that is not the issue.
The UV unit is about 40" in height with two 90 degree bends at inlet and outlet. Before installing the unit the pressure was fine. Will have to play with this one. Need to study your Hydraulics 101 post. Very comprehensive and informative. Thanks
 
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Yurij

Active member
Aug 19, 2020
25
Warren, NJ
Not a risk to the heater, risk to staining the pool surfaces and turning blonde hair green. Unless you are using trichlor too, that is a risk to your heater.

What is your pool surface? Can you add that plus the volume to your signature?
Pool surface is white concrete, Volume is 32,000 gallons. I don't use any other chemicals due to heater risks. Outside of Alkalinity and PH additives usually at pool opening. CYA is maintained and checked weekly with ColorQ 7 unit. Very acccurate. So far no green hair from bleach blonde swimmers :)
 
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Yurij

Active member
Aug 19, 2020
25
Warren, NJ
UV systems add no benefit to outdoor pools. They get plenty of UV.

As for head loss, that is entirely due to the UV unit. 1.5" to 2" bushing has very little head loss so that is not the issue.
I looked into this a bit further and decided to install a flow meter that will be located down stream from my Pool Frog XL chlorinator, right before water returns to the pool. I need to obtain a measurement and understand the current flow rate returning to my pool and decide what to do from there. It's easy to change out from 1.5" to 2" piping but will hold off until I understand where I stand. In the meantime I'll read your article. Thanks for the feedback. By the way, I noticed most on this site prefer SWG systems and not much content on UV systems. Would be interesting to get some unbiased opinions of the pros and cons of each and compare.
 
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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
In the meantime I'll read your article. Thanks for the feedback.
You've been a good sport. Based on your equipment items, I could foresee several discussions about some of those items. As a new member who has already incorporated various pool equipment items not recommended by TFP, it's easy to feel overwhelmed by the replies once our members see anything about ozone, UV, mineral packs, and other such items. Please don't take it personal. Other members have found TFP post-installation with such items previously installed only to learn that it may not be best for their pool. In the end, it's your pool and you will do what you wish, but we feel obligated to give you all the information to make the best decision for you. We've learned that many salesmen or installers either don't know the chemistry all that well, or have alternative motives for selling such items to enhance their business operations. None of that here. Put a key word or two in the search feature up top and you'll see tons of discussions. In addition, below in another thread that I don't think anyone has shared wit you yet. You might want to take a look at this one also. Have a good day.

 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,733
Pleasanton, CA
I looked into this a bit further and decided to install a flow meter that will be located down stream from my Pool Frog XL chlorinator, right before water returns to the pool. I need to obtain a measurement and understand the current flow rate returning to my pool and decide what to do from there. It's easy to change out from 1.5" to 2" piping but will hold off until I understand where I stand. In the meantime I'll read your article. Thanks for the feedback.
I am not sure what flow rate is going to tell you.

Also, I'm not sure you know this but with a pump like yours, when you reduce head loss, GPM increases but so does the energy use and the extra flow rate rarely means you can run the pump any less so you end up using more energy, not less.
 

Yurij

Active member
Aug 19, 2020
25
Warren, NJ
I am not sure what flow rate is going to tell you.

Also, I'm not sure you know this but with a pump like yours, when you reduce head loss, GPM increases but so does the energy use and the extra flow rate rarely means you can run the pump any less so you end up using more energy, not less.
Understood. I like to decompose problems into digestable parts. Flow rate is a data point that will tell me how long it takes to turn over the pool, which will help with energy usage estimates. Thanks again.
 

Yurij

Active member
Aug 19, 2020
25
Warren, NJ
You've been a good sport. Based on your equipment items, I could foresee several discussions about some of those items. As a new member who has already incorporated various pool equipment items not recommended by TFP, it's easy to feel overwhelmed by the replies once our members see anything about ozone, UV, mineral packs, and other such items. Please don't take it personal. Other members have found TFP post-installation with such items previously installed only to learn that it may not be best for their pool. In the end, it's your pool and you will do what you wish, but we feel obligated to give you all the information to make the best decision for you. We've learned that many salesmen or installers either don't know the chemistry all that well, or have alternative motives for selling such items to enhance their business operations. None of that here. Put a key word or two in the search feature up top and you'll see tons of discussions. In addition, below in another thread that I don't think anyone has shared wit you yet. You might want to take a look at this one also. Have a good day.

You're spot on and I kind of got the impression there are many strong opinions here. But, as mentioned, I'm here because I like the hobby, flexible, open to learn, and share experiences. You have to have fun in your spare time. :)
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,733
Pleasanton, CA
Understood. I like to decompose problems into digestable parts. Flow rate is a data point that will tell me how long it takes to turn over the pool, which will help with energy usage estimates. Thanks again.
If you are using turnovers to determine pump run time, then you are going to run the pump at lot longer than you need. 1-2 turnovers per day is a myth that has circulated on the internet for far too long. Proper sanitation, circulation and skimming are not related to turnover.


 

Yurij

Active member
Aug 19, 2020
25
Warren, NJ
If you are using turnovers to determine pump run time, then you are going to run the pump at lot longer than you need. 1-2 turnovers per day is a myth that has circulated on the internet for far too long. Proper sanitation, circulation and skimming are not related to turnover.


That's fine, but it doesn't hurt to know. I like data and making informed decisions. I'm curious. From my point of view, regardless of how many times you decide to turn over in one day, I am targeting one complete turn over in minimal time. (At full power) Then see how I can cut this down by understanding how the pump behaves in low energy mode. I understand running in low energy mode has benefits compared to competing a turn over and then shutting off. The flow meter will help me understand what is going on. I'll probably end up tweaking between the two modes to reduce power consumption and maintain a crystal clear pool. :)
 
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