Liner Pool Care

[Jasheon]

I have a few questions about a liner pool care, I took over a liner pool around in September of last year. Everything was perfectly fine but once November came around the customer told me that she was going to take care of the pool in the winter and was going to contact me in May once it warmed up and they were ready to swim.

So the winter went by and they called me in the middle of May. I go over there and I noticed that the pool has developed A LOT of wrinkles at the bottom of it. The pool is only a year and 4 months old. The pool did not have wrinkles back in Sept. My guess is that the pH level got way too low and developed wrinkles. Is there a way that a company could drain the pool and fix the wrinkles? Also I have noticed lately that at the bottom of the pool there are these dark spots, it's like dark clouds but they are underneath the liner itself. I tried brushing/vacuuming/netting etc to see if i could feel it, I cannot. Any idea what in the world these black spots are? I am just taking a shot in the dark here, but maybe it's water that has settled underneath the liner?

Also, I do not have access to liquid chlorine where I live, and bleach just won't cut it. Should I be adding stabilized Chlorine Tablets or Cal-Hypo ones?


Thanks!

[aylad]

Without current water testing numbers, we can't tell you whether to add stabilized chlorine or cal hypo. If you'll test with drop-based kit, and post numbers, we can better advise you. You're right, there is no liquid chlorine in Louisiana, but I use bleach very successfully in my pool (I'm near Shreveport). I just run my stabilizer up higher than most to compensate for the climate difference.

Odds are good that the pH got too low and caused the wrinkles, but they are also good that the ground water is so high in our state that pressure from the water, especially if it's pooling under the liner, has caused them. Again, testing numbers will help us there. Also, if there's water pooling under the liner, I'm sure the black spots are black algae or possibly mold. NOthing you can really do if it's under the liner, but bleaching the heck out of it (in a controlled fashion) will help if it's on top of the liner.

As far as draining a pool, especially with our ground water, it usually will make the liner unuseable again. If it's not above ground, the water table will likely "float" the shell, if the company doesn't know what it's doing.

Janet

[waste]

As I haven't seen you yet, welcome to the forum!

Aylad has you covered with the possibilities - is the liner puckered in small areas or more like a spider's web in the shallow end, leading towards the deep?

I've been doing IG liner pools almost exclusively for the past 10 seasons and don't mind sharing the tips and tricks I've picked up

It's GREAT to see other pool dudes come here to try to perfect their mastery of pools!

[Jasheon]

It an above ground pool, I will get the chemical readings next week and post them.

[aylad]

You're not waiting a week in Louisiana without chlorine though, right??

Janet

[Jasheon]

No of course not, I went over there yesterday.

[Jasheon]

Here are some pictures I took today, you can see the gray/blackish stains. What do you guys think they are?

http://i35.photobucket.com/albums/d1...Picture006.jpg
http://i35.photobucket.com/albums/d1...Picture003.jpg
http://i35.photobucket.com/albums/d1...Picture002.jpg
http://i35.photobucket.com/albums/d1...Picture001.jpg

Test readings today were,

Chlorine levels below 1ppm
pH 7.3
TA 210
CH 185
CYA over 100

I cannot get accurate readings on my CYA tests due to my test kit and high water temps here in Louisiana. Lamotte says that my CYA tests will be inaccurate with water temps over 85 degrees.

I am going to have to start using Cal-Hypo tabs from now on in this pool, I need to get that TA lowered and by adding Stabilized tabs it keeps making my pH levels decrease due to their low pH level.

I really need to drain the pool some and put in fresh water, the CYA level is way too high as well.

[waterbear]

Test readings today were,

Chlorine levels below 1ppm
pH 7.3
TA 210
CH 185
CYA over 100


I am going to have to start using Cal-Hypo tabs from now on in this pool, I need to get that TA lowered and by adding Stabilized tabs it keeps making my pH levels decrease due to their low pH level.
You will be using trichlor for a very long time if you are trying to use it to lower the TA. Just use muriatic acid since it takes a LOT more acid to lower TA than pH by any appreciable amount.
I really need to drain the pool some and put in fresh water, the CYA level is way too high as well.

Depending on the TA of the fill water you use this could lower your TA also (if it is lower than the TA of the water in the pool.)

[Jasheon]

Waterbear, I read on here I think that the stabilized tabs have a pH reading of 2 or 3. The Cal-hypo tabs have a pH reading of 11 or something. Someone correct me if i am wrong.

If i keep adding stabilized tabs they will decrease my pH, and i wont be able to add acid to reduce the TA.

Next week when I go there I will drain about 3 or 4 inches from the pool.

[waterbear]

Waterbear, I read on here I think that the stabilized tabs have a pH reading of 2 or 3. The Cal-hypo tabs have a pH reading of 11 or something. Someone correct me if i am wrong.

If i keep adding stabilized tabs they will decrease my pH, and i wont be able to add acid to reduce the TA.

Next week when I go there I will drain about 3 or 4 inches from the pool.

Just a caution, we are getting into advanced chemistry here that is probably better in the china shop. Mods, please move if you see fit.
The effect of the pH drop from trichlor are cumulative over time. 1 lb of trichlor wil drop the pH by only about .5 or .6 and that is not going to make a big difference in TA at all. To lower TA enough bicarbonate has to be converted to carbon dioxide and that has to be allowed to gas off (which then causes pH to rise again).
Also, part of the pH drop is from the reaction of the chlorine when it oxidizes something. The reaction is slightly acidic. Unstabilized chlorine sources such as cal hypo and liquid chlorine are esentially pH neutral in use. Initial addition raises pH but then the acidic readtin neutralized the rise. Stabilized chloirne sources (trichlor and dichlor, which are very acidic and slightly acidic respectively) have a net acidic reaction over time that eats up TA as it keeps bringing the pH back up, the buffering effect talked about.

Bottom line is this. If you are going to use a stabilized chlorine source (CYA aside) you need to have a higher TA than if using an unstabilzied chlorine source. In fact, the last CPO manual I browsed through recommended TA of 100-120 for stabilized chlorine and 80 -100 for unstabilized chlorine, chlorine gas, and SWGs.

Now a TA of 210 is high but the question you need to ask is how stable is the pH. IF the pH rise is staying within acceptable limits between your service visits then don't worry about it and just add acid as needed. IF your pH is always too high when you test the pool on service calls then work on lowering the TA.

With a CYA of over 100 you are gong to need to drain and refill (or run higher FC levels with an unstabilized chlorine to compensate) but if you are dealing with high TA fill water then trichlor is certainly something to consider using for a period of time after the drain and refill, as long as you monitor the CYA. This also depends on the type of filter. If it is a cart or bump type DE then I would not use trichlor but if it is a filter that is backwashed on a regular basis (sand) then each backwashing will have a small dilution effect on the CYA levels as you remove and replace water and makes using trichlor a bit more managable.