Stains in Fiberglass pool

[DavidD]

Marie,
I have not added a sequestering agent yet but had planned to after I did the ascorbic acid treatment. I would usually then backwash/replace DE and add more sequestering agent after all is said and done. Maybe I'll try just the sequestering agent first and see what happens. I'll let you know.
Now let me clarify, these stains are not that noticeable in full sun but usually in low light, such as evening, and I notice them more than others (maybe OCD?).
One observation I have made so far is that the stains appear to be occurring where the gel coat was sprayed in intervals. This is the only explanation for the almost perfectly straight lines that divide my pool in to 3 equal parts. I know that when gel coat is sprayed, you can usually only spray up to about a gallon or so at a time due to "kick off " times (the time in which the gel coat will start to cure). So it appears that where one part overlapped the other, staining is more prone. Makes we wonder if maybe there are slight indentions or something in these areas that collect the stains. After all, fiberglass/gel coat/resin is not absorbent so the stains occur at these locations for some reason.
Either way, It really isn't that big of a deal and if I had to do it all over, I'd still choose the same pool, stains and all!

[mbar]

Me too Dave! I love the fiberglass, stains and all. I noticed the same thing - my stains always seem to appear in the same places. My opinion is to put the sequestering agent in first, so whatever metals are still in solution will be filtered out. Then again when you do a stain treatment, so that the metals will bind to the sequestering agent as soon as they go into solution. My plan this year when I open is to put in the sequestering agent, slowly raise my chlorine, and balance the pool. I plan to run low cya (about40) so that I don't have to keep my chlorine very high. I also plan to keep my ph around no higher than 7.4. What I think, and it is only what I think so far, is that when the ph is low, the chlorine is more potent, which can let any metal in the water fall out onto the surface of the pool when the filter is off and the water isn't moving. But on the other hand low ph keeps the pool on the acidic side, which keeps the stains in solution, making the sequestering agent able to get rid of the stains before they fall onto the surface of the pool. This is why it is so confusing. So in my opinion lower ph with lower chlorine levels should keep the pool less suseptable to stains. I really don't know yet!! I am still in experimental stage - every time I think I know how and why the stain comes, something happens to destroy my theory. Anyway this is my plan for this year, I will let you know how it goes. I think keeping the filter running for 24/7 for the first couple of weeks after adding the sequestering agent is the most impotant thing when I first open the pool. I have never had stains when the pool is first opened, it seems it happens when I shock the pool on opening. That's why this year I plan to put in the sequestering agent first before taking the water up to shock levels. Keep me informed on what you learn too, maybe we can figure this out!

[wsmith002]

Every year it is the same thing for us. Once the chlorine level goes up, light brown stains on the floor, steps and sides begin to appear. StainFree (Vitamin C) will take then up for a couple of days then back them come. Pool builder just says it's something I'm doing. The only place not stained is the seems on the bottom.

[cajunfla]

OK, I guess I will be joining this thread. I have the dreaded brownish stain all over the fiberglass below the waterline. Did a partial drain today, mostly to get rid of HIGH CYA. Tried scotchbrite pads, even pressure washer. NO JOY !

Going to try the Stain Remover (ascorbic acid) from Leslie's. The lable says I must use with Metal Free to pevent re-occurance. Buying that brand because I don't want to wait for a shipment. I will add to pool after re-fill is complete, and post results of stain removal tomorrow.

Jeff

[mbar]

Here are some observations that I have noticed over the years with stains. Make sure you add enough sequestering agent. It won't hurt anything if you put more in than you need, but it will leave some metals free to stain if you don't. Keep your ph on the low side - I like to keep mine between 7.2 - 7.4, no higher. Keep you chlorine consistant - don't let it drop down to where you will have to shock. High chlorine levels will let any metals that are free in your pool to precipitate out and land on the pool. When you start to see the stain forming, add more sequestering agent and bring your ph back down to 7.0 - 7.2., and keep the filter running 24/7. It seems that the stain will lift with the sequestering agent and low ph if it hasn't become too embedded. If the stain is localized, put a little ascorbic acid in a stocking and rub it on the stain - this way you don't have to do the whole treatment.

[cajunfla]

Leslie's Stain Remover (ascorbic acid) and Metal Free worked great !! Stain disappeared in minutes.

Jeff

[charlescab]

I used to use leslies all the time and it does work well but gets expensive, as I have to remove stain weekly. Every time I raise the chlorine it comes back.

I used to do this and it took about 3 days to do it (leslie's method)
1) Lower the chlorine (about $10 for the bottle)
2) Use metal free (I think $20)
3) run for a couple days
4) Back flush
5) Destain using Leslies Ascorbix acid ($40 for 2 pounds)
6) Raise the chlorine

But I have found that the ascorbic acid is a contact agent, and a cheaper way to do this is
1) Order ascorbic acid from MSM MSM (Half the price 12.50 a pound as opposed to leslies $20 for a pound)
http://www.msm-msm.com/faq.html
2) Turn off the pump for 1 hour
3) Drizzle very small amounts of the ascorbic acid around the edge of the pool (about .75 pounds max for a 15000 gal pool)
4) Let ascorbic acid float down the sides of the pool
5) Let the pool sit for 4 hours, then turn the pump on. The next morning its perfect.



I have had this problem for 3 years and at the beginning of every pool season I have spent countless dollars lowering the chlorine, using metal free, and using ascorbic acid only to have it come back even when the tests at the pool store say there is no metal in my pool.

The method above costs me about $10.00 a week