Max Chlorine PPM for Fiberglass Pools

[ThePoolFool]

Fiberglass pool owners: Anyone know what the recommended maximum for Chlorine PPM is for a white fiberglass pool? For my spring startup regimen, I have been treating my water with 18 ppm using Chlorox (checking 2 or 3 times per day), and I was wondering if it is safe to go higher than that.

[waterbear]

From my understanding fiberglass pools are not affected by high chlorine levels. In fact, my builder used straight 12.5% chorine to get some organic stains off the surface while mine was being installled. Don't know if that was good or bad but it didn't hurt the pool at all.

If you have no CYA then that level might be a bit high but if you have high CYA then that level is not high enough. See this thread for details
http://www.poolforum.com/pf2/showthread.php?t=365

[duraleigh]

Poolfool,

I don't have an answer but am bumping this back to the top. I'm like waterbear....I think it's okay to boost it (Cl) way up but I'd like to hear some more confirmation.

[duraleigh]

I'm bumping this to the top once more. I am really interested in a definitive answer. Not doubting waterbear....I think he's right..... but I am hoping some of you FG owners can confirm.

If FG is not suceptible to Cl damage, It would seem to make sense to advise much higher levels when shocking a gunite or FG pool.

I constantly see posts from algae-ridden users who "tip-toe" up to shock level and, because the FC starts to drop the minute they add the dosage, they never obtain shock (breakpoint)....prolonging their agony.

Am I correct in assuming that suggested shock levels for FG or gunite pools could safely be raised say to 50% higher levels than we currently suggest for vinyl pools?

[DavidD]

I don't have a scientific or definitive answer either. I do have a FG pool and have "shocked" up to 25ppm once without any adverse affects, other than staining. This is supposedly due to metals in the water however I have my doubts since everyone who has tested my water says there aren't any metals. I haven't figured it out yet but it cannot be caused solely by the High FC level since I generally have to do an "ascorbic acid stain treatment" a few times each season and rarely have to shock. My pool color is the same as Waterbears, see his picture in the upper left hand corner of his post. I also know someone with a white pool and they use dichlor to shock their pool. No telling what level they've gone up to as I have seen numerous empty bags around after they opened. Back to your original question, I can't imagine a FC level of say 50ppm hurting the fiberglass. As an avid boater, I have used some pretty nasty and acidic stuff on my boat without any adverse effects. I would venture a guess that at some point, chlorine (or acid for that matter) could cause the gel coat to oxidize (develope a white haze on the top layer). What that point would be I haven't a clue. Let me stress that this is only a theory.

Dave

[reneep]

I have a 10K gal fiberglass pool and have fought staining for several years with weekly shocking. Now that I have discovered this forum, I realize that using 3" tabs has caused my CYA level to be extremely high, causing the need for more CL, causing more staining. Now in the process of drain/refill to lower CYA and begin a bleach only plan. Having said all of that, the finish on the pool does not seem to have been affected.

[aylad]

reneep,

I don't think that the higher chlorine levels are causing your staining, unless it's because they are causing metals to precipitate out of the water. Have you had the water checked for metals?

Janet

[cajunfla]

reneep,

if your stains are a brownish-yellowish color, I found the answer in another thread here. I had those stains also, everywhere under the water, sides, steps. I was using tri-chlor tablets at that time. Put some vitamin C (ascorbic acid) tablets in a sock, and wet it. Then rub on a part of the stain. If the stain goes away, here is the fix. Buy some ascorbic acid in a powder form. The label may recommend some sort of 'metal free' also. I added the proper amount of each for my size pool, and the stains disappeared in minutes. It was the metals leaching out of the water and grabbing onto the pool. Has not returned yet. I have switched to the BBB method. Good 'ol hurricane Alberto added about 3 inches of water to my pool last night and today, so that will help lower the CYA level, as I had to drain some off.

[waterbear]

. My pool color is the same as Waterbears, see his picture in the upper left hand corner of his post.
My pool is white, the blue color is just from the very clear water and the way the sun was that day.

I have beent trying to reseach this and can find nothing definitive on how high a chlorine level is safe for FG. San Juan pools (the manufacturer of my pool) does state in their maintenance manual that high sanitizer levels can damage the gelcoat but don't say how high is too high. I have also seen several times that FG doesn't require as high a FC level as vinyl or gunite because the coating is non reactive (this one doesn't make any sense to me since it is the water that needs sanitizing, not the pool shell) and I have also come across an interesting tidbit about calciium a few times. It seems the gelcoat has some metals in it's makup (cobalt?) and soft water can leach them out which is why calcium is recommended for FG at about 175 ppmto help prevent it in much the same way it prevents leaching the calium out of a plaster pool. Calcium is a metal and this does make sense chemically. This topic has been discussed in a different thread but I have run across this several more times. Can't prove it one way or the other, however!
I also ran across some info on fiberglass pipes and how they are recommended for caustic chemicals including sodium hypochorite because they are non reactive. Then I ran across info on fiberglass patio furniture that is not warrentied against damage from chlorine.
Very conflicting info!:(

[DavidD]

My pool is white, the blue color is just from the very clear water and the way the sun was that day.(

Amazing, in the sun mine looks the same. Sorry about that!

Dave

[waterbear]

Nothing to be sorry about, I take it as a compliment that my blue water looked like I had a blue pool!;)

[duraleigh]

Evan,

Great post. Thanks for the research you do on all your info.

You even dumbed it down so I could understand it!:D

[reneep]

I have had water tested many times (weekly), put way too many chemicals in the pool and spent WAY too much $$. Now I am trying to get it in shape and under control with the BBB method.

I am fighting very high CYA numbers. When I started the pool company reading was 192. I have drained about 4 inches of water off 3 times and purchased a drops test kit. Todays readings are listed below. Please give me guidance as to what to do. When I tested the CYA after the second refill it was down to 100. I have not tested after the third refill. I have had the pool for 6 years but have always just taken the water to the pool store and followed their directions so really, I am just learning to manage the chemicals. I have I think I may need to add bleach to raise the free clorine? The water looks and feels great. I do have a staining problem and will treat with stain out or something similar once I get the balance correct.

Thanks for you help. I have spent a lot of time reading and you guys do a great job of simplifying all of this and do not seem to tire of newbie questions. I am glad I found you!

CL 4
TA 170
Ph 7.6
Hardness 0

[mbar]

I have a white fiberglass pool also. I have had my shock levels way up there - this was before I found this forum. I can't tell you how high, but I know I threw bag after bag of shock per the pool store's instruction. As for damage to the gelcoat - I have not seen any evidence of it - I also know that when they repair cracks in the gelcoat, they sand them down, and the gelcoat is pretty thick, so I don't think going high with chlorine for a short time would co any damage. On the other hand, I really think that there is something in the fiberglass itself that makes it very suseptable to staining. I thought about the calcium too - but the first year I got the stain, was the spring I switched to chlorine. The pool store had me put in tons of calcium, and tons of shock, because my water was green. They even came over with an extra pump - I kept telling them that the water did not seem due to algae - it looked like a chemical reaction - but they said, no, it just needed more calcium and shock - needless to say I ended up with a cloudy lime green pool. I went to a different pool store and had a water test - my calcium was at 550!, and my chlorine was higher than their test went. They suggested a drain of 1/2 the water and refill. It was when I drained that I saw the yellow stain all over the pool - that's when I decided to learn how to take care of my pool myself. So, I researched staining and have been researching it ever since! The conclusion I have come to is that fiberglass is very suseptable to staining - metals will always find a way into the pool, but the fiberlass seems to react very easily to any metals (calcium is a metal), and a combination of high chlorine with high ph seems to make a stain cocktail in fiberglass pools. I have tried different chemical balances in my pool, and the one that has seemed to work the best is: Low ph 7.2 - 7.5, medium cya, so I can run my pool on lower levels of chlorine, alk about 80 - 100, and calcium at about 125 - 200. I tried running very low calcium, but had stain - so I think Waterbear is right about the metal pulling out of the fiberglass if there isn't any calcium in the water. But most important is to KEEP SEQUESTERANT IN THE WATER AT ALL TIMES. I also notice that keeping the filter running 24/7 works for me. Keeping up with my pool so I don't have to shock is one thing I try to do, but I do shock every now and then, and I make sure my ph is low when I do. Hope this helps all fiberglass pool owners - I love my pool, and even though it doesn't sound like it, it really is very, very easy to take care of.
The blue water in the white fiberglass is due to the refraction of the light from the sky (according to a very smart person). That's why it appears bluer some times more than others.

[scotty5x5]

" Buy some ascorbic acid in a powder form. The label may recommend some sort of 'metal free' also. I added the proper amount of each for my size pool, and the stains disappeared in minutes"

Where would you find ascorbic acid in these quantities and how do you determine a proper dose?
Scott

[mbar]

Here are two links to ascorbic acid:
http://www.chemistrystore.com/Ascorbic_Acid.htm
http://www.msm-msm.com/store/agora.cgi?cart_id=%%cart_id%%&product=Vitamins&user4=Ascorbic%20Acid
You will need about 1/2 to 1 pound of ascorbic to 10,000 gal.
Feel free to ask any questions on the stain treatment.

[cajunfla]

the Blue Hawaiian customer service rep told me to maintain the calcium hardness at a MINIMUM of 350ppm. Also have info from a pool magazine saying fg pools should be 250--400ppm.

[waterbear]

My San Juan builder/dealer told me that calcium was not needed in a fiberglass pool (or a vinyl pool) but told me to keep the calcium levels same as gunite since I have an acrylic spillover spa with a marble spillway and grouted tilework all around the spa that the water cascasdes down when the spillover is operating for the sake of the tilework and spillover. (and I have a heater). My builder specializes in fiberglass but he installs all 3 types of pools. San Juan recommends 200-400 ppm calcium for their pools in their maintenance manual.