brown stains along rim of pool, vitamin c does not remove stain, idea?

[vinouspleasure]

We have brown stains that extend 4-6 inches under the water line, are on the steps and also there are some bottom stains. I held two vitamin c tablets on the stain to no effect.

what can I try next? thanks, jd

[mbar]

What kind of pool do you have? Do you have any metal in your water? What are your test numbers? If you give us some more info, we will be able to help you better. Welcome to the forum!

[vinouspleasure]

thanks for the offer of help and welcome, recently received test kit, here are my current numbers
c 1.5
cc 0
tc .5
ph 7.2
alk 50
cal 120
cya 0

28,300 gallon ig gunite pool

- I'm moving my alk up, 2lbs of baking soda at a time.
- Moving my chlorine to 3...tough without cya
- stopping by pool store for cya today.

[mbar]

You are on the right track - When you test for chlorine the first number is Free chlorine, the second number is combined chlorine, the total chlorine is adding fc to cc. So I don't know where you are getting the .5 - sometimes if you wait a while after adding the drops to test for cc, the water turns slightly pink - this isn't cc. You just want the results of when you first put in the 5 drops. You do need to get cya in the water - put half of what it says to put in on the bottle. You can always bump it up later, and the only way to get rid of it is by draining water. Shoot for 30 - 50, it can take a week for it to show up in a test. You can put it in the skimmer or put it in a sock and tie it near a return jet. You will also want to move your calcium up to 200 - 400. This is necessary in a gunite pool.

As for the stains - they may be organic, which will come off when you get some high chlorine in the water. If they didn't come off with Vitamin C, then my guess would be they are organic. You can also try a pumice stone, or something that will rub a little harder on the gunite. They sell a stain eraser at the pool stores that is good. It can clip on the bottom of a skimmer pole. It rubs the stain off, like a gentle pumice stone. Or you can just bring your clorine level up high and it will fade them in time.

Hope this helps, feel free to ask any questions you may have.

[vinouspleasure]

thanks for the tip on cal. that was off my radar. It looks like I'll need a lot. 15.75 lbs moves it up 50ppm...so thats around 45lbs(!) to get into range.

my tc calc was just a math error. my fc had moved up but I forgot to adjust the tc number.

[mbar]

Watch the calcium - I would try adding 10 first and see where you get - I added calcium according to the directions and it went higher than expected. Same as with cya - you can always add more, but once in there you have to drain the water to get rid of it.