New pool, need to figure out what to tackle first.

[Agentbolt]

Purchased a new house with a pool in October '11 and it came with a large-ish ~20,000 gal pool, its irregularly shaped(kind of like a v shape) however and also goes from 3 feet to 10 feet at the deep end so the capacity is a guess. I called the local pool builder that has their name stamped in the steps and they said it must have been built before '95 because they have no record of it but only kept records from after then.

The pool looks great, I have no idea how old the plaster is but its not cracked or peeling or anything, and the water is crystal clear. I'm concerned about the chemistry first, as I'm assuming stuff like a replaster, I can worry about later as I'll just know when to do it because it'll start looking bad.

I purchased the standard 2006 Taylor chemistry set you all recommended and here's the #s for it after switching to bleach and acid for the past 4 months:

PH 7.4 (Tends to creep up after a week or two, I lower it with muriatic acid)
FC 10.5 ppm (prior owner was using stabilized pucks, I switched to bleach immediately)
TA 90
CH 540 (!!)
CA off the charts, my guess is like 150-200

I live in Tucson AZ so the pool is not really “closed”, I'm still trying to tweak stuff to get the chemistry good over the winter. For the CYA and CH I know the solution is drain and refill, to try to keep things from getting ridiculously expensive I've been backwashing to right down to the bottom of the skimmer and refilling about once a week, but the numbers aren't really going down. Tucson water is EXTREMELY hard (the Taylor kit says my tap water is at 270) so I hope there's nothing more drastic I need to do. Any suggestions?

 

[duraleigh]

Welcome to the forum :lol:

For now, keep the pH low (7.2 - 7.4 or so) and keep the FC high....about right where it is.

You really shouldn't lower your FC ANY until you can work the CYA down to around 50 and, with what you are doing, that may take awhile. You may not be doing too much more than staying even with evaporation so your CH and CYA will remain high indefinitely....not good.

It seems to me your choices are to continue as you have been and just live with the extra chlorine costs or bite the bullet and do a couple of 50% drains and get your CYA reduced so you can run FC around 3ppm or so and put your CH back into a more normal range.

Actually, if you'll keep that pH down low, you can successfully manage the CH issue without much extra cost but the high CYA sooner or later is a problem in almost all pools.

 

[Agentbolt]

I had kind of hoped backwashing, splash out, and the like would slowly just take care of it themselves as long as I wasn't adding CYA, because while evaporation raises the CYA ppm, I thought the water being pumped out would have more CYA in it, so you'd still have a net loss. No, huh? :-(

Some posts have suggested lowering TA can help with high CH, how's that work? Also, even if my “stop making it worse and pay for the extra chlorine in the meantime until it fixes itself” works, am I hurting anything in the meantime? I'd assume not, considering the lunatic who lived here before me was happily putting 4 trichlor pucks in at a time during the summer, in addition to apparently throwing in a bag of de-icer every night for years, and he didn't wreck it.

 

[duraleigh]

because while evaporation raises the CYA ppm, I thought the water being pumped out would have more CYA in it, so you'd still have a net loss.

You are correct. I was having a small senior moment but I am better now!

No, you are not hurting anything and, if you manage it carefully, your pool may do just fine where it is. Most anecdotal info we get on the forum however suggests that, sooner or later, (usually around August) many pool owners do not keep their FC high enough to compensate for the high levels of CYA.

 

[Agentbolt]

Sorry to sound dense, when you say people tend to learn their lesson around August, what's happening to them? Algae I'd assume? I know black or mustard algae with my CYA this high would probably necessitate changing out my pool water for bleach followed by setting the pool on fire, so I certainly plan to be fairly dedicated in keeping an eye on the chlorine levels. I guess I might get lazy about it but if it seemed like I didn't have the time to check it a few nights a week once the warmer weather comes, I'd probably just bit the bullet and do a 50% drain and refill and see what happens. I guess my main concern is how the pool will hold up until I get stuff where I'd like, if the high CYA was maybe eating plaster (vaguely remember seeing someone mention that can happen on this forum) or if the very high CH was causing any problems. Sounds like I'm pretty much good, so thanks for the info

SO the next question I have is: what kinds of problems can I expect to run into based on the fact that I have a very old, very unknown pool? Sounds like the pool is at least 20 years old. When I bugged the prior owner about how long it's been since he re-plastered it, he said "oh about 10 years" but wasn't able to be more specific, and honestly I'm not 100% sure i could believe any answer he gave as he was an older gentleman and starting to clearly slide into some mild dementia. What I do know for sure is that it's one of the old school very light blue plaster pools, it currently has no cracks or peeling, and the water looks fanstastic, so now I just want to keep it that way as long as possible before the thing starts falling apart. (I say things like "starts falling apart" but I honestly don't know if pools have a shelf life you just HAVE to strip it down to nothing and basically re-do the whole thing after some time frame, or if good maintenance will keep a pool looking great pretty much indefinitely.)

 

[Richard320]

You're doing good, keeping the FC up there because of the CYA.

I started with similar numbers. I recall the CYA tested out somewhere around 220 initially. If you dilute your sample 50% with tap water and then use that for the CYA test, you can double the result and get a closer approximation.

My CH climbs and climbs, actually hit 1100 at the highest. I worked at reducing CH and CYA by using pool water on the lawn, then refilling. Same amount of water used, just ran it through the pool first. We were on water restrictions, so just draining it down the sewer wasn't an option. My big breakthrough came with the winter rains. I directed a raingutter downspout to the pool. It works out to about 3X. So a storm that drops 2" of rain puts 6" into the pool. 6" of CYA-CH-free water! Soon as it started raining, I started pumping.

Anyway, managing a pool with your numbers CAN be done, and I'm proof of that. Incidentally, your CH may not be as high as you think. When I switched from manual swirling to a speedstir, it dropped considerably. Use Pool Calculator and keep the CSI close to zero. Play with the numbers, sometimes dropping TA 20 points is all you need, or put the pH at 7.3, stuff like that. To lower TA, get pH down to 7 - 7.2, then aerate the water. I just set the spa to full on mode, you may need to get more creative if you don't have a spa. The search feature should help you find ideas for an aerator.

 

[Puffin]

Do you or anyone know if Reverse Osmosis (RO) is available in the Tucson area? If so, that could also be a way to go. RO will take care of both the high CH and CYA. You'll have to weigh the cost against drain and refill.

 

[JamesW]

Do you or anyone know if Reverse Osmosis (RO) is available in the Tucson area? If so, that could also be a way to go. RO will take care of both the high CH and CYA. You'll have to weigh the cost against drain and refill.

This company operates out of Tucson, AZ. They provide RO treatment for swimming pools.
Clean Water Products
1870 W Prince Road, Suite 3
Tucson, AZ 85705-2962
(888) 828-1508
http://www.cleanwaterproducts.net/Swimming_Pools.html

 

[Melt In The Sun]

They are a pretty new outfit. I got something in the mail from them very recently, and the cost was several times what it would cost me to drain and refill the pool.

 

[Agentbolt]

I'll keep an eye on things, IF I broke down though and decided to just destroy the CYA I'd probably opt for renting a pump from Home Depot to drain it into the sewer, rather than paying a fortune for the r/o truck to come by. Thanks for the info that they're here though!

One last question, is the CSI number kind of the end-all of the chemistry numbers? Like, if my CH is a bit too high and my PH is a bit low and my blah is blah, but my CSI is right around zero, does that mean my pool is pretty much good as-is? I was reading the "Is Saturation Index Always Reliable" post and it seems to say that as long as your CSI is in spec, it doesn't really matter what the specific parameters are (obviously chlorine is a seperate thing)

 

[Melt In The Sun]

That is correct, sir. I'm in Tucson as well, and my CH is about 1000. I've done just as you described: keep and eye on the TA and pH and scale won't form. This spring I will be replacing most of my water. My CH has gone from ~250 to ~1000 in 2 years, so I figure it'll be an every other year thing.

For most people, it's easier just to maintain your pool with the recommended pH/TA/CH levels, but some situations (like ours) require a little more thinking.

 

[RobbieH]

Let one of the guys experienced in high CH to chime in, but adding borates to your water may help you control the scaling, and might help with your pH swings. Get your TA where you want it before adding the borates though.

 

[chem geek]

The borates can buy you more time so that you can acid before the pH gets too high to potentially cause scaling, but usually when it comes to scale the borates are more helpful in preventing scale forming in a saltwater chlorine generator cell. If you keep the TA lower then it should slow down the rate of pH rise and be easier to keep the pH from getting too high and that combination will help prevent scale in spite of the higher CH. A CH of 1000 is still quite manageable.

 

[duraleigh]

One last question, is the CSI number kind of the end-all of the chemistry numbers?

I will likely go to my grave fighting this notion but I haven't been feeling all that well lately, anyway!

My observation is that CSI is completely irrelevant in MOST pools. If you maintain your CH, pH, and TA within the guidelines suggested here you will never be required to calculate CSI unless you have a genetic predisposition to make things harder than they need to be.

If you are unable to maintain those parameters (as when your fill water has VERY high CH) then it comes in to play and needs to be addressed to keep your pool from precipitating calcium. However, there really are not very many pools that fall into that category......some, but not very many.

Each time CSI is mentioned on the forum, I would like to see some type of asterisk or other qualifier so we don't give newbies or the casual visitor the impression that his pool will catch on fire (I love that mental image :lol if they choose to ignore the calculation.

BBB that we advocate is based on hard science and research that has been done (kudos to chemgeek, et al) by VERY valuable members of this forum.....we would be hopeless/helpless without their contributions. That said, I hope the thrust of the forum continues to support the everyman pool owner like me who's idea of a nice day is to worry more about adeqaute ice on the beer than CSI.

 

[Melt In The Sun]

That is correct, sir. I'm in Tucson as well, and my CH is about 1000. I've done just as you described: keep and eye on the TA and pH and scale won't form. This spring I will be replacing most of my water. My CH has gone from ~250 to ~1000 in 2 years, so I figure it'll be an every other year thing.

For most people, it's easier just to maintain your pool with the recommended pH/TA/CH levels, but some situations (like ours) require a little more thinking.

I agree with Dave, hence my elaborate asterisk in the above post.

 

[chiefwej]

I know this is an old tread, but I'm also in Tucson and was looking at RO treatment. Looks like there are several people that offer the service here in Tucson. Price is around $300, compaired to about half that for the cost of the 20,000 gallons it would take to just drain and refill. My CH is now around 750 but the fill water is 250. So how low would the RO leave it? Would it really be worth the extra cost for RO to get the CH even lower?

 

[Richard320]

I know this is an old tread, but I'm also in Tucson and was looking at RO treatment. Looks like there are several people that offer the service here in Tucson. Price is around $300, compaired to about half that for the cost of the 20,000 gallons it would take to just drain and refill. My CH is now around 750 but the fill water is 250. So how low would the RO leave it? Would it really be worth the extra cost for RO to get the CH even lower?

When it comes out the unit, zero (as clean as distilled). But of course there's diminishing returns because you're mixing the RO water in with the old. They'll stop it when it gets to some recommended CH level. Otherwise you'll end up having to go buy some Calcium Increaser to prevent etching the plaster!