Forum

Replies

• 

  Jon Lemoine November 29, 2011 at 9:28pm

  Hi Gang...

  Got a rather delayed response as I have just joined PGN. The only time I see this ( I am in RI) is when the pool chlorine level stays consistently low. The problem fist came to my attention about 15 years ago or so after I had installed some ionization systems into customer pools. The system was touted as "chlorine free" and admittedly the pool water was clear and sanitary but the fungus problem started to appear. After speaking with the liner factory I discovered the porosity issues of vinyl and that it was not impervious to attack at the microscopic level. The cure at the time, was adding an inline chlorinator to maintain a .5 ppm chlorine level and for the most part the fungus stains disappeared.
• 

  Jay Tucker March 31, 2010 at 1:52am

  Thanks everyone for all of the great info. I have had a few more liners show up with the black fungus in the last 6 months and will be replacing the liners. Tara mfg has a product that treats the pool bottom before a liner goes in to combat the fungus. I have not used it so far but here is the link http://www.taramfg.com/dealersdistributors/stain-barrier.aspx
  
  thanks
• 

  Bruce Hudson February 11, 2010 at 1:41pm

  Bravo! First solution I've read that is like, sooo doable%\ Wish I'd thoughta that.
  
  Glen Brandsema said:

  I too have used this method, fexible sealant is the new duct tape!
  
  ALLEN HUNZEKER said:

  not to overstate the obvious but the use of a large gauge needle attached to a 5cc.or larger syringe wiil allow you to inject chlorine under liner. works well. then (again underwater) apply a dab of anderson's flexible sealant ato puncture and swipe with a finger tip to seal puncture. gotta love a leak guy! you can pocket the money that would have been spent on those chems.
• 

  Glen Brandsema February 11, 2010 at 1:19pm

  I too have used this method, fexible sealant is the new duct tape!
  
  ALLEN HUNZEKER said:

  not to overstate the obvious but the use of a large gauge needle attached to a 5cc.or larger syringe wiil allow you to inject chlorine under liner. works well. then (again underwater) apply a dab of anderson's flexible sealant ato puncture and swipe with a finger tip to seal puncture. gotta love a leak guy! you can pocket the money that would have been spent on those chems.
• 

  Dan Silva May 20, 2009 at 11:15pm

  I have encountered black algae many times. Black algae is like rust, once it's there it's almost impossible to eliminate. I've seen many different methods of trying to treat it, but most of them are just temporary patches. I've done an exhausting amount of research on the topic, and everyone's posts here seem to reinforce the conclusions I've drawn several years ago. There are basically three schools of thought to attacking black algae.
  1. Chemically treat the pool water.- Bottom line, I've never seen any treatment from inside the pool work long term.
  2. Removing the liner and treating it directly (or injecting through the liner, sliding a feeder tube behind the liner, treating the pool base through the surrounding soil, etc.)- These methods are much more effective since you can attack the problem directly with a high concentration, but I've seen it come back after a few years. You still have moist/boggy ground conditions, so even if you completely kill off what's there now, what's to stop it from returning in the future?
  3. Create a physical barrier between the floor and the liner.- This is the only method I'll even suggest to my customers anymore. I don't like the idea of a sheet of poly because if water is a problem, I don't like the risk of the sheet floating/shifting/bunching down the road if the liner floats. For the past 7 or 8 years I've been using a "vinyl stain barrier" paint from a company in Tennessee. It's worked fantastically (even after following up with past customers). It does have a few problems though. It's VERY messy to work with. Also, since it's a paint, it dries instead of curing. Since you're usually painting a damp surface, it stays tacky. This means you can't walk on it or you'll get footprints everywhere when you get out of the pool. Also, it grabs onto the liner making it very hard to adjust when you reset it.
  
  All that said, after years of success with this method, I've decided to make a change this year. I have decided to try applying an epoxy coating to the vermiculite under the liner. Epoxy is durable and will completely seal the surface. It's less messy, and since it cures instead of drying, it should reach it's full, dry hardness even on a damp surface. I think the liner will slide over it relatively easily. I have two jobs coming up with black algae problems. If I'm missing anything glaringly obvious, PLEASE reply to this post before I make a big mistake. Otherwise, I'll let you know how it goes in a few weeks.
• 

  Larry Lee Lonas April 11, 2009 at 9:21pm

  If this subject is still a active discussion , maybe I can add a little more info. Over the last 12 yrs I have probably looked at over 100 inground vinyl pools with this black mold growth under the liner. Alot of people initially treat it Chemically as a algae growth , major shock treatment in addition to a special algaecide. The problem area will lighten up for 3-5 days then come back to its original color / size. What was accomplished in that treatment was stun the growth/sensitively of the mold, but also it confirms that the growth is under the liner. Wet soil conditions due to leaking septic sys, leach field, high water table, by a stream, or on a hill create this environment for this growth. This growth only occures where the liner is touching the sand/vermiculite surface/anyplace that is somewhat porous. That is why you never see it on the wall/steps or the concrete hopper if poured for the main drain. Right now ,as far as I know, the only way to treat this problem is to
  pull back/remove liner and remove the top surface of material/chemically treat existing surface/let it dry and then install new liner.Another way is to lay down some black poly and tape to edges,so it doesn't slide around and then set new liner in. Both solutions may be good for couple years since the causes of the wet soil condition could create problem again.
  The problem in treating the soil is you may be contaiminating the soil with chemicals that could harm the environment.
• 

  Jay Tucker March 19, 2009 at 9:59am

  Jayme,
  
  Very informative post. Thank you! The Ferrous sulfate maybe the same product I had used from Jack's Magic and had good success so far when it was used in 2-3 pools 4-5 years ago. I will look into this.The explanation of the gas (hydrogen sulfide) makes sense as well.
  
  Jayme Gruen said:

  Hi Jay, & Group at large,
  I have had many experiences with "black algae" of the past 20 yrs, but no cures. Common symptoms: Stronger during the summer, tends to fade in the winter, never on the vertical walls, only on the slopes or flats, strong chlorine or low pH temporarily fades the black, is photosensitive meaning more vivid during a sunny day than a cloudy day. I have some evidence that supports my belief that septic gas (hydrogen sulfide) generated by sulfur reducing bacteria in certain fertile soil adjacent to the pools is responsible for this blackening.
  Vinyl is water impermeable but not gas impermeable, meaning that gases such as hydrogen sulfide can migrate through the liner. This type of gaseous transmission will not leave a stain on the underside of the liner. This is consistent with my observations over the years. The water side stains do not show similar underside stains when closely examined. I
  have witnessed numerous liners that have been removed with black stains that have perfectly clean undersides when washed. I have cut liner samples and examined them under the microscope. I have yet to see a liner sample that shows blackening throughout the thickness of the liner.
  A number of years ago I performed experiments soaking ferrous sulfate (not copper sulfate) into the soil adjacent to the pool that had a three foot concrete collar. Ferrous sulfate is well known to chemically reduce (neutralize) hydrogen sulfide. The stains receded over a 3-7 day period but did not completely disappear. My work was submitted to the vinyl makers and written up in Service Industry News. Other companies have replicated my experiment with similar success. A big obstacle in using this approach is that most pools have full decked areas making it impossible to get the chemical close enough to the affected areas. All comments are welcome!
• 

  Jayme Gruen March 17, 2009 at 1:05pm

  Hi Jay, & Group at large,
  I have had many experiences with "black algae" of the past 20 yrs, but no cures. Common symptoms: Stronger during the summer, tends to fade in the winter, never on the vertical walls, only on the slopes or flats, strong chlorine or low pH temporarily fades the black, is photosensitive meaning more vivid during a sunny day than a cloudy day. I have some evidence that supports my belief that septic gas (hydrogen sulfide) generated by sulfur reducing bacteria in certain fertile soil adjacent to the pools is responsible for this blackening.
  Vinyl is water impermeable but not gas impermeable, meaning that gases such as hydrogen sulfide can migrate through the liner. This type of gaseous transmission will not leave a stain on the underside of the liner. This is consistent with my observations over the years. The water side stains do not show similar underside stains when closely examined. I
  have witnessed numerous liners that have been removed with black stains that have perfectly clean undersides when washed. I have cut liner samples and examined them under the microscope. I have yet to see a liner sample that shows blackening throughout the thickness of the liner.
  A number of years ago I performed experiments soaking ferrous sulfate (not copper sulfate) into the soil adjacent to the pool that had a three foot concrete collar. Ferrous sulfate is well known to chemically reduce (neutralize) hydrogen sulfide. The stains receded over a 3-7 day period but did not completely disappear. My work was submitted to the vinyl makers and written up in Service Industry News. Other companies have replicated my experiment with similar success. A big obstacle in using this approach is that most pools have full decked areas making it impossible to get the chemical close enough to the affected areas. All comments are welcome!
• 

  Robin Reed March 17, 2009 at 6:34am

  I believe what you are talking about is a fungus or bacteria, not algae. I have found that keeping a chlorine reading in the pool prevents it from showing up. When the liner is replaced I recommend cleaning the bottom with bleach before installing the new liner to help prevent reoccurence. I seem to recall that some companies have used fungicides as well, but I have no experience with them.
• 

  Kevin Misley February 20, 2009 at 1:42pm

  I read a few of the comments from treating areas with chlorine or putting plastic sheeting behind the liner. One comment was the goodies were taken out of the liner ingredients some years ago and this problem arose. I think there is some credence to that. Essentially there is not much that can be done because the fungus comes from behind. In my 23+ years experience I've seen liners that develop this stain are from high water conditions around the pool. It was predominent with vermiculite bases as opposed to sand bases.
  Check out the property landscape not just the pool when considering a liner replacement. Very flat properties and developments usually are swampy and hold lots of water. Properties located at the bottom of a hill or ravine become holding areas for water. Soil conditions such as clay will hold water. If the property has beautiful green grass and is somewhat soggy when walked upon even in the summer months without and irrigation system, it should raise a red flag. Floating liners indicate high water also.
  
  Years ago I replaced a liner in the late summer and the property was always wet. Upon removing the liner we hit water-lots of water. The panels were severely rusted indicating serious water issues.
  My suggestion is to scope the entire property, ask questions about any liner floating problems and suggest using a darker print liner to make stains less noticeable. As long as the customer is informed both verbally and in wrighting about this potential problem, you will be a hero for being honest.