I've been trying to eliminate black algae per instructions here at TFP. At the same time, my gunnite pool needs to be resurfaced. When a pool guy came to give me a bid on the resurfacing, I asked abt the black algae. He said that covering the algae with a new layer of plaster would kill the algae, which needs sunlight to survive. Does anyone have experience with this particular issue?
Will re-plastering a pool eliminate black algae?
- Thread starter Valiyo
- Start date
Maybe but I'd say not for those reasons. If you have old plaster with nooks and crannies where algae hides you'd be eliminating those. But you wouldn't cover up the algae because they chip out the old plaster before resurfacing.
- Jun 24, 2021
- 16,074
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
You should have a full chip out done. You should not plaster over existing plaster. It should remove all the black algae.
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Plaster Installation and Maintenance - Further Reading
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I asked the pool guy how they prep for resurfacing and he said they rough up the surface (mallet, I think) but don't remove anything. And they do an acid wash. Would that be adequate?
- Jun 24, 2021
- 16,074
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
- Jul 21, 2013
- 65,306
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It may work or it may not. If it does not your pool guy will be long gone and you will be left with the delamination problems.
It all depends on the integrity of your existing plaster and how good his mallet is.
If he did not mention putting on a bonding coat over your existing plaster then he is cutting corners.
A full plaster removal is always the preferred way to replaster.
- May 23, 2015
- 25,707
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Don’t let a “pool guy” do the job. Talk directly with a pool plaster contractor that pool builders use when subcontracting out their pool builds. You want an expert in the process which is a person/company whose only job all day everyday is to plaster pools. Using a “pool guy” to do plaster work is like asking your landscaper to do your root canal surgery … I’m sure if he watches enough YouTube videos he’ll get all the steps down but do you really want to be his patient??
Ask yourself how you got black algae in the first place.......you didn't get it from the plaster.
Black algae typically begins from PROLONGED periods of inadequate chlorine. Unless you change how you are chlorinating your pool, black algae will come back, regardless of how many coats of plaster you apply.
Black algae typically begins from PROLONGED periods of inadequate chlorine. Unless you change how you are chlorinating your pool, black algae will come back, regardless of how many coats of plaster you apply.
My pool guy = the re-plastering estimator for the company that installed my pool. I asked about a full chip out and this was his response: "We can do extra some extra prep work like acid washing and things like that. Removing all the plaster is not ideal as you never know how good the plaster may be inhered to the gunite, this causing divots throughout the pool trying to jackhammer off the old plaster that then would require brown-coat coverage to smooth it out again and then plaster could be applied. This could easily double the quote."
- Jul 21, 2013
- 65,306
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Your pool guy does not know the proper tools and techniques to chip out plaster without damaging the gunite. Jackhammers are not used. Flat chisels are used. Pointed chisels can damage the gunite. There is also high pressure blasting that can remove the plaster.
Find another company to replaster your pool. Get 3-4 quotes from qualified companies that do both replastering and plastering new pools. As duraleigh stated, determine why you got the b-alage in the first place: bad chemistry. I went away and CL was not added as I asked, so I am dealing with it now. I am not not going to have my pool replasterd to fix an algae problem, I suggest you work on that now before you have your pool replasted, and by someone that knows the process and what they are doing - good luck.
- May 23, 2015
- 25,707
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Flat bladed air chisels will remove the plaster uniformly. Another more expensive option is sand blasting/water blasting the plaster/gunite.
Leaving the old plaster has lots of risks. You get what you pay for -
“Quality is never cheap, and cheap is NEVER quality.”
Leaving the old plaster has lots of risks. You get what you pay for -
“Quality is never cheap, and cheap is NEVER quality.”