Black Algae of Doom! Extremely Resistant to my attempts

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fox_and_hound

fox_and_hound

0
Jun 19, 2013
79
Sunny Florida
I have been chasing low chlorine and black algae in my pool. Not sure why am I constantly dealing with low chlorine and no clue how to kill this black algae.

I maintain the pool weekly and this summer, there was very low to zero chlorine reading during my weekly test. I was previously shocking the pool and using powdered chlorine and tablets weekly. This worked for a year. Then, with the Summer weather and raining, the chlorine level kept reading low and I noticed large black algae splotches on the walls. I think its black algae. So, I switched to liquid chlorine and tablets bc pool store said this was a stronger method. But still, the chlorine level is non-existant after 6 days. Tried to brush the algae, it didnt budge. I bought a black algae product at Pinch a Penny, that was a total waste. I used a Chlorine puck rubbing it directly on a small test area and that works but its a lot of work and Im hesistant bc it might damage the diamond brite? I guess I'll need to get a scuba mask to do it in the deep end and then brush it off after a few hours?

CYA is normal which is strange, I thought this would be due to low CYA. I verified my results at pool store, same thing. They found that all levels were normal, calcium was a slight bit low but they said that was not important for algae. Need help :(
 
That's the way chlorine works -- it is consumed DAILY so you need to add it to the pool every day or two when using chlorinating liquid or bleach, not just weekly. In a hot sunny area in a warm pool, 2 ppm FC per day loss is pretty typical and in some pools it is even higher (but usually not more than 3 ppm per day). Are you not physically at home during the week to be able to spend less than 5 minutes per day to add chlorine?

You've been on this forum for a while mostly discussing circulation and other topics, but have you read the Pool School in particular with regard to maintaining pool water chemistry and using chlorine at the appropriate level for the CYA level (i.e. the Chlorine / CYA Chart)?
 
If you are testing weekly it would be common, normal even to find that the chlorine level is low. Depending on the amount of sun and bather load almost any reasonable amount of chlorine you added last week could easily be used up in the seven days. Being in Florida you likely need a higher CYA level and testing at least bi-weekly. That or an automated chlorine dispenser.
How much use do the pool and spa get weekly ??
:google: https://www.google.com/#q=automatic+pool+liquid+chlorine+dispenser

It would also be helpful if you posted what you bring FC up to and what you find it at a week later just so we know what we're talking about. CYA level too.
 
I am renting out the house and can only service pool once a week until tenants leave in late Nov. The black algae gets worse (wider area) every week! The family has 4 kids and lots of friends. Every week pool has all sorts of sand and dirt. Lots of use!

What is the best, most longest lasting method to Chlorination? I am only finding this to be an issue during Summer/early Fall and when lots of people are using pool so Im not sure Im ready to do automatic Chlorine dispenser yet. It sounds awesome though!

Free Cl before pool service- 0ppm
Free Cl after service- 4ppm
CYA before service- 60
CYA after service- 60
 
You are going to have to find a way to get and keep FC in the pool!

I wonder if it would be worthwhile to use pucks for now for the daily FC with adding liquid chlorine as often as possible.

Just so long as you KNOW that the pucks WILL push your cya up. You will have to drain some of the pool once you have daily access to the pool to lower the cya.

If you are planning on renting the house out again you are going to have to find a daily way to keep FC in your pool. Once a week is not going to do it. BUT first you have to get rid of the black algae. That is going to take some time and bleach.

Good luck!

Kim
 
You are pretty low on chlorine for a CYA level of 60. The chart http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock recommends a maintence level of 7 with a minimum level of 5. Drop below 5ppm and that's when you start to have problems. I would start to go for 8 or 9ppm as a target when you add. it still isn't likely to make it a week but it would have a better chance of having something in there.

Rental property puts this in a whole different ball park. With the pool dropping below 5ppm and especially hitting zero FC between additions you're also inviting something growing in there like bacteria or a virus that could make someone ill. It's why you have an algae problem but it's also something that you might be liable for should someone become seriously ill since you are the one maintaining it (I'm not a lawyer, don't know what's in the rental agreement).

If it were my property I'd check it once a week but I'd make sure the tenant was legally responsible for the maintenance.

Other than a pump the only other thing I can think of is using chlorinating tabs but as Kimkats pointed out they will slowly raise your CYA level.
 
Ok I see what you guys mean, what should be my target CYA and target Chlorine in South Florida? I notice the chart really varies. I realize that if CYA gets too high, pool has to be drained and refilled a bit. Im willing to do whatever to treat the algae. I never had this problem when I was shocking weekly but then again, the weather wasnt as hot! Should I shock weekly to get a higher FC?

I hear you but Tenants never even know how to maintain a pool...LOL. They dont clean filters. You cant count on them to top off the pool so pump doesnt run dry. I would rather do it than have them break something bc its me who pays for repairs of things that broke appearing to be normal wear/tear. So, its me or a pool company. :p Pool company often disappoints!

Im going to do pool school tonight!!
 
For your location I would set my CYA level at 50. Your target FC level is 8-9 and never below 5. Target the high end of the range. That gives you wiggle room so you don't fall below your min of 5.
If you lose more than 3 ppm of FC a day bump the CYA level up to 60.
Have you considered a SWG or chlorine injection system ? ?
 
You guys are amazing. Yes, increasing CYA and FC cured the algae, I didnte even have to clean it manually.

Unfortunately, the increased Chlorine is a beast on my psorasis. After swimming daily, now I have plaque psorasis (which was before just a small dermatitis area of small bumps).

Does a salt system allow for reduced chlorine, how much? Should I make a new thread?
 
I am by no means a medical professional but I can tell you that chlorine is often pointed to for skin conditions when, in fact, it is irrelevant.

How do you know chlorine is the cause?

Weren't you renting this house/pool?
 

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fox_and_hound said:
Does a salt system allow for reduced chlorine, how much? Should I make a new thread?
Click to expand...

No. You still have to have the same amount of chlorine for your cya level whether you use bleach or a swg.

Also a salt system requires around 3000 ppm of salt to be in the water. If your skin doesn't like salt then a salt system probably wouldnt be for you. Using bleach as the source of chlorine would also add salt to the pool but it would take a long time to build up to 3000 ppm.

It kind of looks like there is no chlorine from your post. Im not a doctor either but bacteria, germs and viruses and other such isnt going to be good for anyone, especially if you have open sores on your skin.

Who takes care of the pool?
What are the test results?
 
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