Stains and test results..........

[ozres]

I posted this on another category, but didn't get any help. So I've moved it here. Anyone have any suggestions?




First of all, thanks Ben for this educational site. We've had our pool three years and thanks to your test results, it's been easy to keep up with. However, this year when we opened the pool, we had a stain problem. Some stains were from oak leaves (thanks to the neighbor's trees!), but the worst is a "track line" in the deep end of the pool where Kreepy didn't kreep.

Here's the history.
Upon opening, I purchased many gallons of bleach, probably 30+ and shocked the devil out of the pool, keeping my CL levels above 20. We had an algea problem and I couldn't get my water to completely clear. After reading this forum, I added polyquat. Now the algea is gone and the water's clear.

I'm using a combination of bleach and tri-chlor pucks to keep my chlorine levels up. I know the tri-chlor adds CYA, but we're out-of-town a lot and can't add the bleach when we're not home. When we're home, I'm pouring in bleach, but using the pucks when we're gone so I don't come home to zero chlorine and yucky water.

But the Kreepy tracks are still on the bottom of the pool and there's a nice scum line around the waterline. We've brushed, scrubbed, etc, but it won't go away.

The pool's gunite and about 24,000 gallons.

Here are my numbers from this morning...........

7.0 FC
0 CC
7.0 TC
7.5 PH
90 TA
150 CAL
100 CYA

Base on my forum research, my CYA is too high and preventing the CL from getting rid of the stains. (FYI, some of the oak leaf stains did brush off in the beginning.) Am I correct? Do I need to do a partial drain and get my CYA back to 30-50. Then shock with bleach to eliminate the stains?

What'd y'all think?

Thanks,
Marla

[mbar]

Welcome to the forum, I will try to help all I can.
First your chlorine level is not high enough for your cya. You should have a minimum of 8, and run it somewhere between 8 and 15. You will need to get to 25 to shock. Here is the "Best guess chart"


Stabilizer . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm . . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . . 8 ppm . . . . . 15 ppm . . .. 25 ppm

Second your calcium is not high enough for a gunite pool. It should be between 200 - 400. You will have to add some calcium, but don't add what it says on the container. Add less, and check the next day - the only way to get rid of too much calcium is to drain and refill, just like cya.

You can do a partial drain and refill to lower your cya, but you can also run your pool with a high cya as long as you keep your chlorine levels in the right place. It may be easier for you to keep higher cya since you are away alot.

Your alkalinity is good.
You have no cc, but sometimes you can be starting on algae without it showing up, so it wouldn't hurt to take your chlorine up to shock levels and leave it there for a while, it will help to get rid of the stains. A chlorine of 7 in a pool with cya of 100 will not lift the stains - it will barely keep algae at bay. You can try to crush up some chlorine tabs, or just rub them on the stains and see if they go away. If they do, then they are organic stains and will go away with bleach. If they don't rub off with chlorine, then you can try crushing up some vitamin C tablet (ascorbic acid) and put them in a sock and rub them on the stains. If the stains lighten up with the vitamin C, then the stains are from metals.

Hope this helps, let me know if you have any more questions.

[ozres]

Thanks Marie for the information.

When we opened the pool, I kept the chlorine level over 20, (usually over 25) for 5+ days. The stains that were obviously from leaves (in a nice leaf design on the bottom of the pool!) did brush off fairly easily.

However, the Kreepy tracks in the deep end didn't even fad. I'll try to scrub them with crushed up pucks and then try the vitamin C tablets. Can I just use regular vitamin C tablets? Do they need to be white? I think I've got some chewable orange-flavored ones. Now that I think about it, the chewable vitamin C would probably dissolve too quickly! Right?

Thanks for the help.

Marla

[mbar]

I think any vitamin C would work. Even laying a tablet on the stain should let you know if it is lifting. Fast disolving is good - ascorbic acid is a powder. You can also use ph down if you have any - put it in a sock and rub it on the stain, or let it set on the stain for a while, not too long, and see if it lifts or lightens.