Cannot maintain FC above 0.5

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audioter

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Jul 10, 2012
10
I've been a reader of this forum for quite a while and I really appreciate all the help and time everybody puts forth to help people like me.

I have been having a lot of trouble with my pool keeping FC above 0.5.
I had a white mould problem (tissue paper mould etc) earlier this year and I can't seem to get rid of it. It is under control and the water is blue and clear except for build up over time on the floor of what looks like brown particles which I can vacuum and clean.
I purchased the testing kit and my specs are below. I know my TA and pH are low and I am adding baking soda and soda ash to bring them up.

The real problem is yesterday I dumped 4.5lbs of Cal-Hypo 68% to get the FC to 16 to try and shock the pool. This was based on the chart on this forum for a CYA of 45 and used the pool calculator. Later last night I checked the FC and it was again 0.5, although CC had dropped to 1.5. I then added 382 oz of 6% liquid chlorine and immediately checked the FC which was around 4. I assumed it wasn't higher because it needed time to circulate.
This morning the FC is again 0.5 ppm.
This is not the first time I cannot hold FC above 0.5 ppm.
I do not want to keep adding more chlorine but I am at a loss.

Side note, when I add the Cal-Hypo I get a fair amount of brown silt forming. This did not happen with the bleach. I don't know what this is. My CH seems ok but I am new at this.

Thank you in advance for any thoughts advice or help, and I apologize if this has been answered already.

Pool test results:
FC 0.5
CC 2.5
TA 50
CH 250
CYA 45
pH 6.8
 
Welcome to tfp, audioter :wave:

First from now on please put your test values in your post and not your signature, so we have a running record.

audioter said:
I do not want to keep adding more chlorine but I am at a loss.
Click to expand...
Yes you do!

You need to do the shocking process. With that high CC and loosing that much FC, you have algae in your pool that needs to be killed. Make sure you read the shocking process carefully and follow it. It is a process and will take some time and a lot of chlorine. For now I would not use the cal-hypo, since that also adds calcium to your pool. Use bleach/liquid chlorine to keep the chlorine level at your shock level ( which is 16 ppm FC, from poolcalculator.com and 45 ppm cya).

Let us know what questions you have.
 
Whatever is in your pool is using up the chlorine as fast as you're adding it. You need to be testing as often as possible and adding bleach whenever you see the FC level drop so that you're always maintaining it at shock levels (but no more than once per hour). Add your chlorine to get it up to shock levels. Retest in an hour and if it's dropped add more chlorine to bring it back to shock levels (or slightly above so that the drop will still allow you to be at shock levels). Repeat. When I shocked, I was adding chlorine to maintain my FC every 2-3 hours at first.

If you're allowing your FC to drop below shock level, you're just prolonging the process and wasting money. It may take a lot of bleach, but the end result will be worth it!
 
White water mold is rare in chlorine pools, but if the chlorine levels are too low for too long then it can get established. Once established, it becomes a plague like yellow/mustard algae or black algae where it takes a lot of effort to get rid of it and where you need to thoroughly get rid of it or it will come back. White water mold doesn't like sunlight and it is likely hanging out in your piping and possibly filter. I'm not sure if it shows up behind light niches as does yellow/mustard algae, but it would be worth checking there as well. The prescription is to shock heavily (lower the pH first to 7.2 or so before you raise the FC to very high levels). I would essentially follow the instructions for getting rid of yellow/mustard algae.
 
Thank you all for your insight. It looks like my problem is more serious than I thought given the white mold. It is really reassuring to know somebody understands my problem (the pool guys here had not heard of white mold and didn't know what to do - in fact they just added more CYA thinking lack of stabilizer was the problem which has made this harder as I need to use more bleach now).

After reading the posts, shocking process and shocking for yellow algae this is what I would like to do. Please let me know if anything looks wrong.

1. Start Saturday early AM to allow for repeated checks and addition of chlorine over the weekend
2. Vacuum pool to remove buildup
3. Clean cartridge filter
4. Remove LED lights from niches
5. Attach polaris and fountain to sterilize these at the same time (is this a good idea or should focus on the pool and sterlize these some other way?)
6. Add 6% liquid chlorine (HomeDepot Workforce Outdoor Bleach) to FC of 27 (for CYA 45 and yellow mold shock). Will need 1209oz or 7x182oz jugs.
7. Brush ENTIRE pool, including skimmers, light niches, steps etc
8. Close electric pool cover to try and sterilize pool cover surface
9. Every 1-2 hours check FC and CC and add more bleach to maintain FC of 27, brush pool again, close cover
10. Repeat until CC is less than 0.5 and overnight FC drops less than 1

However, I still have some questions.
A. I have an electric pool cover. I think the mold may be hanging out on the surface of the cover that touches the water (in addition to piping and the filter). I can't think of a way to clean the cover from the underside. I will add water to the pool to raise the level so as much of the cover is in contact with the FC 27. I hope this will sanitize the cover. Any better suggestions?
B. I am confused as to when to stop. I will stop when CC<0.5. But at that point my FC should be at 27 or close. At that point do I monitor to see overnight FC doesn't drop by more than 1? If so I will have a really high FC (27). This does not seem safe to swim in? Is this the correct way to know when to stop?
C. Is HomeDepot Workforce Outdoor Bleach acceptable?
D. Should I try to sterilize the polaris and fountain at the same time or just focus on the pool for now?
E. I read somewhere that lower pH is better for chlorine to work. My pH is 6.8. Should I just leave it there, or bring it to 7.2 or 7.5?

Sorry for all the details and questions. I just don't want to make any more mistakes. I thank you in advance for any corrections on the process or help with my questions.

History of the problem: The mold problem started because of a faulty trichlor tablet dispenser that was clogged. So the chlorine level was not maintained. I had closed the cover for to go out of town blocking out sunlight without realizing the faulty dispenser. On my return the water was filled with mold because of the block in sunlight (as mentioned above white mold grows in the dark) and lack of chlorine. Newbie mistakes and lack of water testing capabilities. I have fixed these errors.
 
a. Do the best you can. I would open it partially and brush underneath with a soft brush just to make contact with the pool water

b. You stop the shock process when...
1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1ppm.

you can swim at shock level

c. No. Use plain, unscented Clorox only...do not use that outdoor stuff.

d. Never a bad idea to clean everything as much as possible

e. pH should never be below 7.0 7.2 - 7.8 is suggested normal values

You are going to need A LOT more chlorine than that. Shocking your pool is much more than the one time dose.

read "The ABC's of Pool Water Chemistry" up in Pool School.

Then, read "How to Shock Your Pool" and follow that article exactly.
 
Thanks for the answers duraleigh and chem geek.
I guess my post was not clear, I do anticipate needing a lot more chlorine. The 7x182 was just a starting estimate. I am going to purchase three times that starting requirement to be sure I have enough to get going. I also will not use the outdoor stuff. I found bleach with 6% hypochlorite on the label at ALPS for $1.50 for 96 oz. I think I am going to go with this.
Lastly, I have read the shock process carefully and plan to follow it - I expect to continue maintain shock levels for quite a while and not just use a single dose.
I will also raise the pH to 7.0-7.2 before beginning.

However, I have another question. I was inspecting my LED light fixtures and I cannot figure out how to get them out to sterilize the niches. There is no screw to release. They niches look just like my returns and there is a grey plastic collar around the LED light but nothing else. The grey collar has four notches at the quarters. Any advice on how to get them out? I don't want to snap something inadvertently. Thanks in advance.
 
audioter said:
6. Add 6% liquid chlorine (HomeDepot Workforce Outdoor Bleach) to FC of 27 (for CYA 45 and yellow mold shock).
Click to expand...

Here is where I'm confused. The Pool School article on Mustard Algae(which is what I assume is most applicable) says to shock at normal (not Mustard Algae) levels until OCLT passes and the other criteria for ending shocking process are met. THEN to raise levels to Mustard Algae levels as listed in this post - keeping these levels up for 24 hours and ensuring that all things that have contact with the pool (tools, floats, etc) are either within the pool for 1 hour or treated outside the pool.

The CYA/FC chartshows a shock level of between 16 and 20 (40-50 CYA). The Mustard Algae post referenced in Pool School shows a level of 24-30 (40-50 CYA). The OP is planning on starting out using a shock level of 27 which seems in line with the Mustard Algae level - is that the right way to do this?

Obviously this is not Mustard Algae - so the process could be different. Assuming it isn't for the moment but I could be wrong.
 
It's OK to start out with a higher shock level. It can make the shocking go faster, but it uses more chlorine (due to the higher FC target) that gets lost during the day from sunlight so that's why normal shock is done first to clean up the "normal" things in the pool first and then the higher shock level is done to kill off yellow/mustard algae more thoroughly (regular shock levels kill it faster than it can grow, but not enough to thoroughly get rid of it from poor circulation areas or to get through clumps of it as effectively).
 

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but it uses more chlorine (due to the higher FC target) that gets lost during the day from sunlight
Click to expand...

And since he has a cover he's going to close the chlorine will not get eaten up by the sun, so most all of it will go to killing the mold.
 
If you would like to make your chlorine more effective, start your process on Friday afternoon or evening. Start up you pump and bring your CL to shock and check it every hour and add CL to get back to shock. I would also throw every toy, float, tool and do-dad that was in the pool in to the pool during this initial onslaught to sanitize them as well. You could continue this as long as you are willing to stay awake.

Doing the shock process at night removes daytime loses to the sun and focuses it all on removing the organics in your pool.

As for $1.50 for 96 oz, the is a pretty good price. If you see 10% for 3.33/ gallon or 12% for $4.00/gallon, you are paying the same price for the same amount of actual chlorine. They are all essentially the same stuff with different amounts of water.
 
chem geek said:
It's OK to start out with a higher shock level. It can make the shocking go faster, but it uses more chlorine (due to the higher FC target) that gets lost during the day from sunlight so that's why normal shock is done first to clean up the "normal" things in the pool first and then the higher shock level is done to kill off yellow/mustard algae more thoroughly (regular shock levels kill it faster than it can grow, but not enough to thoroughly get rid of it from poor circulation areas or to get through clumps of it as effectively).
Click to expand...

Thanks! :cheers: Great explanation!
 
Re: Cannot maintain FC above 0.5 - White Water Mold problem

Wow! Thank you all for the help, ideas and clarification on the process. Especially chem geek for the clarification on starting FC.

Here's what's been going on. I wasn't able to start Friday night but got started early Saturday. I feel pretty good about how things are going.

However, I still can't figure out how to get my LED lights out of the niches. Any advice would be appreciated
The lights are golden and have a grey plastic collar around them. There is no screw for removal (online you tube videos all show a screw for removal of lights - mine are different). I would really like to get into the niches having come so far already. Again, any ideas would be really appreciated.

7/13 Night
Brought pH to 7.2
Baseline readings
FC 0
CC 0.5
CH 200
pH 7.2
CYA 40-50
TA 70

7/14 8:30am
Brown silt all over bottom of floor (Algae?). Vacuumed everything. Took apart and cleaned filter. Can see evidence of white mold in filter.
Began Shock:
Checked CYA again between 40-50. Decided to use values of 50 to be sure I killed everything. Yellow Mustard Algae shock for 50 is FC 29.
Check pH = 7.2 Can begin adding bleach.
Added 13x96oz 6% Bleach.
Brushed everything (skimmers, lights, sides, bottom, stairs)
Closed cover and tried to brush underneath (thanks duraleigh for suggestion). Cover is too long (44 ft) so only got first third. Instead I closed the cover and pushed up/down all around the edge to try and the get the high FC water onto the drier parts.
Testing: FC 31, CC 1, pH 7.2 after above.

7/14 12pm
FC 12, CC 1 (FC dropped 19 I assume because killing stuff)
Added another 8x96oz 6% Bleach to get back to FC 30
Connected fountain to sterilize
Brushed pool. Closed cover. Pushed up/down on cover around edge.

7/14 4:15pm
FC 21, CC 1 (FC drop of 9 - looking better).
Added another 4x96 oz 6% Bleach to get to FC 30.
Connected Polaris. Threw in skimmer net, vacuum base, brush and poles.
Closed cover.

7/14 8:00pm
FC 27, CC 1 (FC drop only 3 - looking good - hopefully everything is dying)
Added 1x182oz 6% Clorox Bleach to get back to FC 30 (I cleaned out ALPS of all the bleach they had :-D. Had to go to Sam's Club, pay $40 membership but can get bleach for ~$1.60 for 96oz and what looks like endless supply).
Closed cover

7/14 9:30 pm
Took baseline for overnight chlorine loss
FC 30, CC 0.5 (FC holding at 30 over short time period)
Closed cover


7/15 7:00am
FC 23, CC 0.5 (FC overnight loss of 7 - still not yet done killing)
Added 1x182oz and 1x96 oz 6% Bleach to get back to FC 30.
Threw in toys (thanks techguy)
Connected vacuum hose to sterilize. Pool now looks like someone littered all over it with all the junk in there :). Thew in my flip flops for good measure.
Brushed pool. Closed cover. Pushed up/down on cover.


I am happy with the FC staying fairly close, although I am still waiting for only a drop of 1 overnight. I am also happy that the pool looks great - water is clear and sparkling. Before I would get sand like silt (I guess Algae) growing on the bottom overnight. Today there was no such stuff. Only very few dark flecks which I think are dead particles.

I will keep FC 30 for another day/night and hope the FC holds tomorrow morning.

Again, the only thing that would make this better would be to figure out how to the get the LED lights out. I hate to come so far and have the mold hide out in the niches.

Bleach use so far - 26x96oz, 2x182oz jugs. But it is working! Maybe I should buy stock in bleach manufacturing?

Long post apologies - any thoughts appreciated.
 
Thanks JasonLion. That did the trick. Was able to get collars off. Feel better that everything I can sterilize is being sterilized.
iSmile - :-D Gotta have fun with it right?!?

7/15 12pm
FC 24.5, CC 1. Still loosing FC 5.5 every 5 hours.
Added 205 oz bleach to get to 29.
Hoping the loss will stabilize tonight.

I will keep bringing FC up beyond 29.
However, how long should I do this for? I am planning to maintain FC 29 till tomorrow morning, but if I get a loss overnight what should I do? Continue to 29 or drop to 16 as per Mustard Algae shock protocol (maintain Mustard Algae shock for 24 hours then return to regular shock)?
 
audioter said:
I will keep bringing FC up beyond 29.
However, how long should I do this for? I am planning to maintain FC 29 till tomorrow morning, but if I get a loss overnight what should I do? Continue to 29 or drop to 16 as per Mustard Algae shock protocol (maintain Mustard Algae shock for 24 hours then return to regular shock)?
Click to expand...
Either way, once you pass the OCLT, I would still dose up to the Mustard Algae level for 24 hours (after you pass the OCLT) to be sure your done with this white mold.

That means, I think you could drop to 16 minimum for now until you pass the OCLT (or you can keep it at 29 which will take more chlorine, but might get you to a passing OCLT quicker), then bring it up to at least 29 again for 24 hours like the article says: http://www.troublefreepool.com/pool-school/mustard_algae
 
Thanks linen - Makes Sense. I will keep raising FC to 29 for today and tonight and see what the OCLT reads tomorrow. If FC drops by more than 1 I will let it go lower but no less than 16 and maintain at 16 until OCLT passes. Then raise back to 29 for 24 hours as described.
If I am lucky and pass OCLT overnight tonight I will take it back up to 29 for 24 more hours.

7/15 5:00pm
FC 24.5, CC 0.5. Again loosing 4.5 in 5 hours.
Added 253oz 6% Bleach to get back to 29.
Closed cover.
 

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