This is my first time using this site, so please forgive if I do something wrong. I’m a relatively new fiberglass pool owner and have been thrown to the wolves with staining issues which nobody can seem to help me figure out. Most agree that they look like iron stains, but I have done citric and AA treatments as well as over the counter stain removers with only very limited results. One of the last “experts” I consulted told me to discontinue using liquid chlorine because that would stain my pool and to use two tablets per week of the stabilized chlorine instead. When I asked him about the residual CYA problems from using only the tabs, he didn’t seem to understand what I was asking. I went against everything I had read about to follow his “expert”advice only to watch my pool stains grow exponentially worse almost overnight. When I tested, my CYA was around 100. I began dumping/refilling my pool and got the CYA down to 40 and returned to using liquid chlorine daily. However, now the liquid chlorine isn’t held in the pool very long by the stabilizer. I’m so confused about how to do this correctly. Any help would be appreciated.
Confused About CYA
- Thread starter JiggyG
- Start date
Welcome to TFP.
So happy that you went back to using LC. Is your FC relatively stable or is dropping drastically after you add LC?
A CYA of 40ppm should hold your FC somewhat stable for a while. Maybe do a test, then add LC and then test 45 mins later after letting it circulate.
What test kit are you using? Can you post a full set of test results as follows
FC
CC
CH
TA
CYA
pH
You mention FG pool. What is the volume?
So happy that you went back to using LC. Is your FC relatively stable or is dropping drastically after you add LC?
A CYA of 40ppm should hold your FC somewhat stable for a while. Maybe do a test, then add LC and then test 45 mins later after letting it circulate.
What test kit are you using? Can you post a full set of test results as follows
FC
CC
CH
TA
CYA
pH
You mention FG pool. What is the volume?
- Mar 5, 2020
- 3,090
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
Welcome to the forum.
Good on you to ditch this "expert's" advice - if they didn't understand what you were talking about, then there can't have been too much expertise.
Liquid chlorine is the way to go. What's important to understand is that chlorine tabs are very acidic, so they are compensating the upwards pH drift due to CO2 outgassing that happens in every pool. The higher the TA, the more CO2 outgassing - another fact that many "experts" don't understand. When transitioning from tabs to liquid, the pH compensating effect of the tabs has gone, and you need other means to control pH: Muriatic acid. Without controlling pH, metal stains will indeed become a problem. But tabs just add too many problems. Liquid chlorine and muriatic acid are the best way forward for you. For the future, you can start thinking about a salt water chlorine generator (SWG).
The issue you have now with holding chlorine is most likely due to algae that developed while your CYA was so high, so you probably will have to follow the SLAM Process. But to do the Overnight Chlorine Loss Test to confirm this, you first need a good test kit: Test Kits Compared. We can't give advice based on pool store tests or test strips.
While waiting for that, keep adding 5ppm worth of liquid chlorine per day. The correct amount you can calculate with PoolMath.
Start reading through the Pool Care Basics, pay particular attention to the FC/CYA Levels.
Then post a full set of test results as suggested by Herman, and we can go from there.
Good on you to ditch this "expert's" advice - if they didn't understand what you were talking about, then there can't have been too much expertise.
Liquid chlorine is the way to go. What's important to understand is that chlorine tabs are very acidic, so they are compensating the upwards pH drift due to CO2 outgassing that happens in every pool. The higher the TA, the more CO2 outgassing - another fact that many "experts" don't understand. When transitioning from tabs to liquid, the pH compensating effect of the tabs has gone, and you need other means to control pH: Muriatic acid. Without controlling pH, metal stains will indeed become a problem. But tabs just add too many problems. Liquid chlorine and muriatic acid are the best way forward for you. For the future, you can start thinking about a salt water chlorine generator (SWG).
The issue you have now with holding chlorine is most likely due to algae that developed while your CYA was so high, so you probably will have to follow the SLAM Process. But to do the Overnight Chlorine Loss Test to confirm this, you first need a good test kit: Test Kits Compared. We can't give advice based on pool store tests or test strips.
While waiting for that, keep adding 5ppm worth of liquid chlorine per day. The correct amount you can calculate with PoolMath.
Start reading through the Pool Care Basics, pay particular attention to the FC/CYA Levels.
Then post a full set of test results as suggested by Herman, and we can go from there.
Last edited:
- Mar 5, 2020
- 3,090
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
How do your stains react to rubbing a vitamin C tablet directly on them?
Have you used any copper containing algaecides?
Have you used any copper containing algaecides?
- May 20, 2020
- 1,001
- Pool Size
- 13600
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Solaxx (Saltron) Reliant / Purechlor R5
You’ve gotten good advice above, but I’d like to clarify one thing. When you say the liquid chlorine isn’t holding, what does that mean to you? Is it going down within an hour? A day? Etc.
Liquid chlorine is something that generally needs to be added every day. It’s normal to lose 2-4ppm of chlorine per day. So if that’s what you mean by not holding, that’s normal. You just need to keep feeding the pool it’s daily chlorine “snack”.
If you’re losing more than that, and you have a CYA level of 40, that suggests algae which as mentioned would warrant a SLAM Process.
To test whether or not you have algae, you can perform an Overnight Chlorine Loss Test.
Keep us posted!
Liquid chlorine is something that generally needs to be added every day. It’s normal to lose 2-4ppm of chlorine per day. So if that’s what you mean by not holding, that’s normal. You just need to keep feeding the pool it’s daily chlorine “snack”.
If you’re losing more than that, and you have a CYA level of 40, that suggests algae which as mentioned would warrant a SLAM Process.
To test whether or not you have algae, you can perform an Overnight Chlorine Loss Test.
Keep us posted!
I'm so sorry. I'm still trying to figure out how to use TFP and just now seeing all the replies. I have a 10,000 gallon fiberglass pool. I try to keep my levels normally around
FC @ 3
CC @ 0
CH @ 200 (my manufacturer's book says 175-225)
TA @ 115-120 (my manufacturer's book says 120-140)
CYA @ 40 or below
PH @ 7.6-7.8 (it tends to run high especially after shocking)
And to answer your question, yes, the liquid chlorine dissipates almost immediately. I've been blaming the FL sunshine, but I've been really confused as to why I can't keep FC in the pool for more than a few hours if my CYA is reading 40.
Thank you. I'm going to have to get a dictionary and spend some time in the pool school, evidently. My test kit at home is a Taylor-2006. So far I've had good results with my readings; I'm just confused about the overall process, and my pool is taking a beating for it. So THANKFUL TO GOD that I've finally found TFP.
- Jul 21, 2013
- 53,261
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Yes, I did unwittingly add a copper algaecide last year, but the stains predated that long before. When I put AA/Citric Acid into water in one of those sponge scrubbers (dishwashing type), the stains come off with a lot of elbow grease. But when I added the AA/Citric to the pool at 1lb. per 10k gallons, NOTHING! I've also tried United Chemicals Pool Stain Treat, ProTeam Metal Out, and a few others with no results.
Thanks for clarifying. I think maybe it's a bit of both. Yes, the LC will hold for awhile but is definitely gone within a few hours (especially in the hot, Florida sunshine). But also I've noticed that, even though we have had a cold snap with water temperatures 50-60 degrees, I've still been able to see algae forming on the sides of the pool. That confused me because I thought algae only grows in warm water. I'm thinking I need to start trying to revisit the education process on this whole thing since I'm obviously not up to par in my knowledge of the whole matter. Pool basics 101, here I come!
Algae grows when there is insufficient chlorine in the water. The reading of FC of 3ppm is at the absolute minimum so it is likely you have some organics consuming the chlorine. Report back with your findings from the Overnight Chlorine Loss Test
- Mar 5, 2020
- 3,090
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
We usually recommend to rub a vitamin C tablet directly on a stain. If the stain gets easily removed by that without much rubbing, then you're dealing with iron stains, that can be removed with an ascorbic acid treatment:
Ascorbic Acid Treatment - Further Reading
www.troublefreepool.com
If the stain stays but changes colour, usually getting much darker, then you are likely dealing with copper stains that can't get removed with ascorbic acid. But there are other options as described here:
Copper in Pool Water - Further Reading
www.troublefreepool.com