Should I Get a UV unit for My Pool

It looks like I'm going to spend a lot of time on this forum.

My wife and I just bought a house with our first pool. We're moving from a house with lake access to a house with a pool with the thought that it will be more relaxing to just walk out the back door and swim vs. get in the boat to go out and swim. We'll see about that. Had a pool inspection yesterday and the pool and equipment got generally good marks. 33,000 gallon free-form gunite, a sand filter and I don't know the details. I can change the oil on my boat but I don't know the first thing about testing pool water. I will begin reading immediately.

One quick question to get started. The pool inspector (who is a pool builder) recommended a Delta UV setup and said it would cut back on chlorine use. Any opinions on that?

Thanks in advance.

Your pool inspector is full of it; you aren't going to save chlorine by adding a little MORE of what the sun already does a lot!

UV system *never* reduce chlorine use on properly managed pools; they always increase it, due to increased photolysis of the chlorine. This can be a good thing on INDOOR pools, since chlorine photolysis releases some high energy oxidants that help oxidize complex combined chlorines on outdoor pools; but on outdoor pools, a UV system is sort of like putting a trolling motor on a ski boat that already has 150hp outboard Honda!

1. Get a cheap OTO/phenol red drops kit and 12 gallons of plain 8% bleach at Walmart. Test your pool, post the results AND start dumping 2 gallons of bleach in the pool every evening -- till you have a better plan. It is much, much easier to avoid algae, than to clean it up!

2. Order a K2006 testkit, so you can manage pool instead of being 'pool-stored'. You have to understand that inaccurate water testing BENEFITS pool stores by increasing chemical sales! http://pool9.net/tk/

3. ID your pump & filter AND any other equipment. Get make and model numbers. I'll help you find the manuals online. Once you have the info, post it => http://pool9.net/pf-equip-form

. . . that's a start.

If the pool is not covered, you'll get plenty of UV from the sun. It seems the general consensus around here is that the CORRECT UV system MIGHT be helpful for an indoor pool, but is probably a waste of money for an outdoor pool. Be sure to read everything at PoolSolutions.com. It is a sister site. You'll also want a good test kit so you'll know what condition your pool water is in. http://pool9.net/tk/

Enjoy your new pool & WELCOME to the Pool Forum. It's a great place to learn about how your pool should be cared for.

Pappy

Pool Doc and Pappy, thanks for the information. We won't take possession of the new place until July so I'll get back with the details you asked for. Speaking with the seller, he seems to have a pretty good maintenance plan for his pool that I asked him to write down for me. I'm not gonna lie, it's intimidating for a new owner. I will have a hundred questions like how long to run the filter (I think he said he runs it 8 hours a day), etc. I'm reading as much as I have time for on these forums. Thanks again.
PS: I ordered the test kit recommended here. And the current owner has those inflatable solar rings floating on about 3/4 of the surface.

OK, we are still 2 weeks away from closing and taking over the new house and pool. But we went over today and I brought back a water sample to test with my new K2006 kit. I don't know the water temp but the ambient temp was around 82 and I would say with all-day sun the water temp was at least upper 70s. It looked clean and pretty clear. I could see the Polaris 280 in the deep end (8 feet) pretty clearly. I also noticed it has a Hayward Chlorinator (not inline) and the homeowner uses trichlor tablets in the chlorinator. Here are the test numbers:
pH 7.4
CYA 85
CH 270
FC 13.5
CC .5
TA 100

I believe he runs the filter 8-10 hours each day and that's about all I know. What do you think?

Those numbers are fine -- no reason to panic or even stress.

Basically, you could get by for weeks just by pouring 1/2 - 1 gallon jug of bleach into the pool every evening. So, now you have a super simple fall-back plan. ;)

Good to know. Thanks, I appreciate the information.

Things are happening and they look bad. My closing on the new house and pool has been delayed until later next week. The owner has moved out and left the pool care to the neighbor, who only turns the pool filter on in the am and off at night. We stopped over to look around this evening and the water looks a little cloudy and there is definitely something on the bottom and walls. Worse still, the water level is getting low near the top of the skimmers with no real rain in sight. And worse still, the house is on a well so no filling from the house. I managed to find a small porcelain pot to bring some water home to test as best I can. I got a CYA well over 100, FC of 36, CC of 1 and pH of 7.2. I wonder if he threw in a bunch of trichlor before leaving town (he uses it in the chlorinator) because there was some algae or something. I feel like I should do something to fix this so it doesn't become a much bigger problem before I ever get a chance to move in. My first move will be to buy some water to bring the level up. I could use some advice on what to do after that. I need some help, please.

Order a K2006 ASAP => http://pool9.net/tk

Do a full bucket leak test, ASAP. If you have no means to fill the pool, and you have a leak . . . you have an unmanageable situation. How did he fill the pool? => www.poolforum.com/pf2/showthread.php/11252

I have the test kit already and I ordered some fill water from the same local pool fill company the owner uses. They will deliver today or Monday. Talking to a relative who has been a pool owner for 20 years, he has many opinions. One is this: he always adds fill water from his well without staining on his concrete pool, he said. Of course, we don't know what is or is not in his well water. My question is this: If my pool is 32k gallons, and I need to add 500 gallons to restore the proper level, what is the risk of metal staining assuming a normal well with some metals or minerals? Seems like a pretty low percentage of new water. And is there a way to treat or filter the new water to avoid staining? Buying water isn't very desirable.

The starting point is finding out what's in your well water. Well water from limestone strata is ideal for pools; water from shale strata is often a nightmare. It is possible to operate a pool successfully with heavily contaminated water; I've done so on large commercial pools. But it's tricky, and some staining is inevitable.

The first step is to determine whether your well water is a problem or not. Do the metals bucket test => http://pool9.net/bucket-metals

If it is a problem, and if you have the space, you may want to get a 5,000 - 10,000 Intex pool that you can use to pre-treat the water for your IG pool. Trying to treat metal contaminated water once it's IN your pool is a mess. Trying to treat it in a separate pool, dedicated to that purpose, is much, much easier.

I assume your registration address is NOT your new pool's address? (I just looked up your registation, and Googled the address). Otherwise, I'd recommend filling with surface water, which is almost always metal free. You just have to add enough chlorine to make sure the algae and critters die quickly.

I don't think my wife will allow a second pool (I know it's an exaggeration). I'll try the metals bucket test later this week when we hopefully close and take possession of the house/pool. And no, the house you Googled is not the new one, it's the house we're trying to sell. It's time to leave the lake for someone else. I almost never had to worry about the lake water before a swim (except when they sprayed for weed control). Thanks for the input again.

Do the metals test first -- the problem may not be as severe as you fear.

Re the 2nd pool: keep in mind I'm talking about a small pool, 15' round or so, that can be hidden somewhere. You can transfer treated / floc-ced / settled water from the little pool to the big pool via a small sump pump and a 100' water hose! But, hopefully that won't be needed.

Duly noted but I don't think a second pool is in my future. I will struggle with one. Will do the metals test this weekend.
I went to the house today and the water does not seem to be dropping just based on a mark I made 24 hours earlier, so that's not much of a concern. The pH is down to 7.0 so maybe I should add some Borax? That's a question. FC is down to 27, CC is 0 and the CYA is still well over 100. But the water looks really nice and clean. Temp of the water is about 84 degrees. We finally are cleared to close this Friday so I will have daily access this weekend. Looking forward to the first swim since it was 90 today. Thanks.

Yes, add borax when your pH is low.

BUT, with FC=27, you need to retest your pH using a 1:1 dilution of your pool water with distilled water (gallon jug from Walmart; NOT 'bottled', 'artesian', 'spring' water: DISTILLED). Adding distilled water to your pool water will not change the pH noticeably, but will dilute the chlorine. Very high chlorine levels can convert the phenol red into another indicator, with different colors, leading to invalid results.

Finally, we own it. Won't move in for a couple weeks but it's on my shoulders now. Added Borax the other day and the retest of the pH produced a 7.6 and I did the distilled water dilution. Got the first swim in today, check. Water looks good but the chlorine count is still high. I might need to back off the chlorinator even more. Here's the big news of sorts. A guy tested my water straight from the well and he said the hardness was not crazy at 27, but he said there's lots of iron at 3.5. No time to do the bucket test yet since I'm redoing the kitchen. Thanks for all the input.

An update and a thank you. It's now June 2015 and my pool is amazing, in large part due to what I continue to learn here. So, thanks for that. When we opened the pool this year the water was down and I feared a leak. I was thinking it was leaking last year but my lack of knowledge held me back. Paid a company to go in the unheated (62 degrees) water in May and they found the leak at the underwater light fixture. A common problem I discovered. I am now losing about an 1/8-inch of water per day to evaporation and occasional splash. We've had so much rain this spring I actually need to drain some water to stay below the top of the skimmers. Realized a heater was essential and had one installed a few weeks ago. Only used it a few times but it works great and I haven't even used it enough to see a blip on the gas bill. Very happy so far. This is getting long because I think new owners might learn like I did. My auto chlorinator has been empty and I'm running only on the BBB method. Very happy with that too. Numbers just yesterday after getting another 1/2 inch of rain (1/2 inch rise in the pool) were FC 6, CC 0, PH 7.7, and CYA a week ago was tested at 80, which is down from last year when I used trichlor tabs. Numbers are very stable and predictable so far so I guess I'm lucky. Chlorine drop is slow with light use. I cover most of the surface with those solar rings the previous owner left me. I've added an inflatable alligator and turtle and the ducks have not landed in it in the 3 weeks since. Water quality is great. I love my pool. Thanks again for all the helpful insight.

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Yay! Great post!!!

Just a thought... Since your CYA is towards the high end of the CYA range, you might want to consider raising your FC minimum to the corresponding higher end of the FC range. http://www.poolsolutions.com/gd/best...e-chart.html#a

Thanks FBU. I agree with you on the staying on the higher end and normally do. But the rains have been heavy for three days (lowering my FC) and my grandkids were coming that day so I figured I'd add a gallon of bleach after we swam. Appreciate the input.

Quote:

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Originally Posted by Pappy

If the pool is not covered, you'll get plenty of UV from the sun. It seems the general consensus around here is that the CORRECT UV system MIGHT be helpful for an indoor pool, but is probably a waste of money for an outdoor pool.

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FWIW, according to the American Cancer Society, the UV we get from the sun is 95% UVA and 5% UVB. UVA and even moreso UVB can cause skin cancer, but are only moderately effective at killing bacteria and viruses. UVC, the UV that is used for disinfecting, aka "germicidal UV" is a different part of the light spectrum--approximately 254nm. UVC is the UV used in water treatment. UVC does not penetrate the atmosphere, even at the equator, so you don't get the "good UV" from sunlight (although there is some indication that some UVC might be getting through at the south pole.) So UVC is man made down here at the earth's surface.

The combination of UV and ozone are claimed to eliminate chlorine compounds. In my tests, "CC" is always -0-. There is also evidence that chlorine-resistant bacteria and parasites are killed by O3 and UV systems. For some people the evidence is sufficient to use O3 and UV in addition to chlorine. I won't start an argument for or against, as from what I've read here and elsewhere, the Yes/No for O3+UV seems comparable to the Yes or No, For or Against the value of a manual thumb safety on a defensive handgun. Those opposed will not be swayed in their beliefs, nor will those for. Luckily both groups can have it their way, as it is a preference, not a law.

When considered in the context of the entire cost of a swimming pool and spa, the addition of O3 and UV treatment is not much money. Like I said, FWIW.

Hope everyone had a happy Thanksgiving and has a Merry Christmas.
Bill

We've been over this at least a dozen times in the forum. While some of your statements, like "There is also evidence that chlorine-resistant bacteria and parasites are killed by O3 and UV systems" are true theoretically, they are not true practically with respect to any system you are likely to install on your pool. (Well, unless you are willing to spend several $100,000's for a German DIN-standard ozone system, plus several $100,000's MORE, per YEAR, for a team of German system operators living on site.)

I'm not wasting my time analyzing the specific details of the expensive junk you've been sold, just to prove, all over again, that the systems actually sold are useless or worse. And, I'm not going to allow you to waste other people's time, misleading them as you attempt to justify your purchase decision. I've tried to be nice about such stuff in the past, but it doesn't work.

If you want to convince yourself that you haven't been snookered, feel free to do so in the privacy of your own home!

But, I'm not going to allow it here. Please go argue your point elsewhere.

PS. If this is what you meant by the 'other forum' being "close-minded", well, please consider me and the PoolForum close-minded, too.