New member with stain problems

Hello all, I have been fighting a stain problem for over a year, been using a product called Stainaway (acsorbic acid). The instruction on this product wants you to raise chlorine because stainaway eats up chlorine. After reading post on the list..I know that that info is wrong. I went to W-mart and bought their 6-way test kit so I could start to do things right..with your help.
Here are my numbers...

FC= .8
TC= 1.3
CC=.5
PH= 7.6
TA= 90
Hardness=0
CYA=less than 20ppm...dot did not disappear.

I have a fiberglass pool approximately 13000 gal. Water temperature 88.
Thanks in advance

Ron B. Violett
Memphis Tn

First questions, what color are the stains? Have you tested the water for metals?

How are you getting a FC reading of .8 and a TC reading of 1.3 with the walmart kit? It doesn't have that much precision (and it really only tests for TC, not FC since it is an OTO test!). It is quite possible that you have some CC in the pool but the walmart kit will not tell you that!
Your pH and TA are fine. The CH is suspect unless you are filling your pool with softened water (there are some known issues with the CH test in the walmart AqauChem 6 way kit. It is quite possible that your CH is NOT 0.)
What form of chlorine are you using? If you are using a non stabilized chlorine (Sodium hypochlorite or cal hypo) you need to get the CYA level up a bit....30-50 ppm is a good range.

If your staining is from metals then you need to use a sequesterant in addition to the ascorbic acid to keep the stains from coming back. Fiberglass seems to be more prone to staining than other pool surfaces but it is easy enough to deal with. If you can get a water test done that includes testing for iron and copper it would be helpful. Many pool stores can do this.

You did not say if the product you are using was effective removing the stains. If it is then a seqesterant will help prevent their return. If it isn't then there are other treatments that can be effective once the type of stain (metal or organic) is identified.

Waterbear...thanks for your post.

Stain color is light brown...stainaway product works great...but stains come back after a few days.

Chlorine readings were my best guess looking at the color code. The walmart test uses the color after the first 10 seconds as the FC and then after 2 minutes they use that color as TC. Their directions not mine.

I use the tablets for chlorine...I think it is stablized. Will check tomorrow.

Will get water test for metals tomorrow.

Ron.

Waterbear, just got back from pool place with a fresh set of numbers...
FC=.2
TC=.4
CC=.2
PH=7.6
Hardness=100ppm
ALK=60ppm
CYA=3ppm
Copper=.11ppm
Iron=not tested
Total dissolved solids=800ppm
.....Looks like I have metal in the pool...so what should be my course of action to keep these stains at bay ?

thanks again for your help

Ron in Memphis.

I am familiar with the walmart kit directions...I have one;)....OTO is a test for Total chlorine. It will not accurately test FC.
Light brown stain is probably iron. The fact that ascorbic acid removed it easily strenghtens my belief that your stain is from iron.
As far as keeping the stains from coming back it's very simple. Watch your pH (staining usually happens when the pH rises too high) and keep a seqesterant in the water. There are many good ones out there. I have used the Jack's Magic line (Pink stuff for iron, Blue stuff for copper or combinations), ProTeam Metal Magic, and NaturalChemistry's Metal Free with good results but there are other good ones also. It is important to follow the directions in terms of water balance before applying. (some like the pH to be on the high side and some might want the chlorine level droppped a bit). The initial treatment dosage might mess up your water balance by lowering pH and eating up your total alkalinity but just rebalance the water after 20 hours or how ever long the manufacturer suggests. After that just keep up with the maintenance dose weekly or every two weeks and you should have no problems! If the metals are coming from your fill water then it's a good idea to add a little extra each time you add water to your pool.

I am guessing from your numbers that you have recently treated with ascorbic acid since your chlorine levels are very low and your alkalinity is low also. If there are no stains then add a sequesterant, filter for a day or so, and then slowly raise your chlorine level and adjust the TA and then the pH. Try not to let the pH climb above 7.6 to help avoid staining in the future.
Since your CYA is still on the low side you can continue using the trichlor tabs to get it up a bit higher. You then might want to consider switching to bleach as most of the regulars on the forum use it as their main source of chlorine!

Waterbear, thanks for your help...I will begin the process tomorrow and continue to learn from this site and its members.

Ron in Memphis