High calcium keeping stains away...now moving on to BBB

[tdbohannon]

Hello all,
I have been reading the forums here for a while but just now posting for the first time.
Basically, we were having trouble with a pool company causing stains every week when they came out to shock. I fired them and am now back to doing it myself. We were having staining issues (10k fiberglass) every time the chlorine level was raised. The endless cycle of adding AA was costing too much and we were on a roller coaster with the other levels.
As of now, the pool looks beautiful but the water feels dry. Maybe due to the calcium? I'm not sure, but I'm afraid to lower the calcium since it seems to be keeping the stains at bay. Thoughts?

FC 1.0 (added bleach last night after testing and didn't test again this AM)
pH 7.3
TA 100
CH 290
CYA 80
Sorry for size of pic...[attachment=0:21nv19ib]2IMG00024-20090618-1557.jpg[/attachment:21nv19ib]

 

[duraleigh]

Your pool water looks very nice.

You cannot lower your calcium level unless you partially drain and refill.

If by AA, you mean ascorbic acid, then it sounds like you have iron in the water and the chlorine is causing it to precipitate out into stains.

Unless you refill your pool, the iron will always be there so you must keep it in suspension with a sequestrant and with very careful control of your pH and TA. I am not very knowledgeable on the use of sequestrants so I'd rather let others advise you further.

Metals in pool water are very difficult to deal with. You have done well to have your pool looking as nice as it does.

 

[tdbohannon]

Thanks. Odd thing regarding metals, no one has been able to find anything more than a slight trace of copper and no iron whatsoever. We had some work done on the fiberglass about 6 weeks ago and drained half down in the process. The staining issue existed both before and after the drain / fill. Also, I can't imagine what the pool company must have had my CYA at if it's at 80 now just a few weeks after a half drain..

Also, I just checked the chlorine when I got home and it's a ~6, so everything seems to be in line for now. Anyone have thoughts on the issue of the water feeling overly dry?

 

[duraleigh]

what did you mean by AA?

 

[tdbohannon]

ascorbic acid.

 

[duraleigh]

The endless cycle of adding AA was costing too much and we were on a roller coaster with the other levels.

I am a little confused. Why did you treat for metal when the tests didn't show any?

 

[Guest]

The endless cycle of adding AA was costing too much and we were on a roller coaster with the other levels.

I am a little confused. Why did you treat for metal when the tests didn't show any?

If the metals have already stained the pool they very well might not test in the water since they are no longer IN the water.

 

[Guest]

Hello all,
I have been reading the forums here for a while but just now posting for the first time.
Basically, we were having trouble with a pool company causing stains every week when they came out to shock. I fired them and am now back to doing it myself. We were having staining issues (10k fiberglass) every time the chlorine level was raised. The endless cycle of adding AA was costing too much and we were on a roller coaster with the other levels.
As of now, the pool looks beautiful but the water feels dry. Maybe due to the calcium? I'm not sure, but I'm afraid to lower the calcium since it seems to be keeping the stains at bay. Thoughts?

How soft is your water normally? Hard water will have a different 'feel' but it will help keep fiberglass pools from staining as readily, IMHO>
Adding borates to 50 ppm could help with the 'feel' of the water.

 

[tdbohannon]

The endless cycle of adding AA was costing too much and we were on a roller coaster with the other levels.

I am a little confused. Why did you treat for metal when the tests didn't show any?

If the metals have already stained the pool they very well might not test in the water since they are no longer IN the water.

Good point that they may not have showed up if they were 'attached'. Now that it isn't stained, maybe I'll take some in for a test.

regarding the other question of why I used ascorbic acid if no metals were showing up, it was kind of by accident. The local pool store has mostly clueless employees. I went in there 8 years ago when we bought the house and asked them what I should use for a stained fiber pool and they sold me ascorbic acid (without testing for anything). It worked so quickly, that I kept using it and then eventually figured out that it was primarily used for the removal of metal stains. I started buying at the vitamin shoppe for much cheaper by the way.

 

[JasonLion]

Have you been using sequestrant? Once the AA lifts the stains off the surface, you should add some sequestrant to prevent future staining.

 

[tdbohannon]

Have you been using sequestrant? Once the AA lifts the stains off the surface, you should add some sequestrant to prevent future staining.

I haven't recently, but when I did in the past, it didn't seem to make much of a difference. Is it possible that the ascorbic acid is removing some type of stain other than a metal stain? I'm by no means a chemist...

 

[JasonLion]

Sequestrant doesn't usually remove stains. In a few situations it can remove stains, but that isn't why it is used. Sequestrant is designed to prevent stains from forming even when there are metals in the water.

 

[tdbohannon]

Sequestrant doesn't usually remove stains. In a few situations it can remove stains, but that isn't why it is used. Sequestrant is designed to prevent stains from forming even when there are metals in the water.

By didn't work, I meant that the stains would still come back after shocking, even though the sequestrant directions were followed.

 

[Guest]

but sequesterant and higher CH does!
Stains that appear after shocking are metal and if they are brown to yellow in a fiberglass pool they are iron. Both ascrobic acid and sequesterant are needed together to solve the problem. Either one alone won't do it.

 

[JasonLion]

In addition to the CH that waterbear suggests, you may need more sequestrant than the instructions indicate. As a general rule, if the stains appear again, you weren't using enough sequestrant.

 

[tdbohannon]

but sequesterant and higher CH does!
Stains that appear after shocking are metal and if they are brown to yellow in a fiberglass pool they are iron. Both ascrobic acid and sequesterant are needed together to solve the problem. Either one alone won't do it.

Waterbear..what level do you recommend keeping CH at? Mine is at 290 now. As mentioned previously in this thread, I have just moved to the BBB system. I noticed yesterday that my FC had dropped from ~6 to ~2 and that there was some very, very light staining near the water line (I assume from when I shocked with bleach a couple of days ago). A very small amount of AA took the stains away, and they really weren't even noticible without looking, but they were definately there. In any event, it's significant progress from the reaction the last time my pool was shocked (when the CH was at about 100)