Can this algae be "killed" somehow?

[HardTrance9]

Hi all,

Last November 2009 -January 2010 we had some black algae in one pool. The pool walls are somewhat pebbe type or like we say it here "washed sand walls".

A year ago, we shocked the pool following some hints you have over here and it worked good as the algae kind of dissipated. But it is the first time with the pool at summer time (around 100's now) and our friendly algae is back!

All this time we kept the chlorine levels stable and sometimes higher (FC between 5 & 8) for a 11,000 gal. pool. Water today is crystal clear, swimmable, etc., but in the last three weeks we got the pool a little busy + the rise on the temp to find out that the pool walls seemed not be properly sealed when it was finished therefore it has lots of "orifices" (small ones, but not normal on a nice pebble standard pool) and it is THERE where our fellow blacky is hiding and living!!

We took some samples and they are as thick as a noodle thin pasta (sorry, but my first though was "looks like mice poop!")...

During the last process about a year ago, we shocked the pool for several days as this "blacky" was expanding on the walls slowly until we thought we got rid of it...

So now, it seems it has adapted to the chlorine level from the pool?? and I am wondering if there is any special chemical that can be used to get rid of it?

We have suggested to the pool owner to also do the "resealing" work for the walls, but we don't know if that will happen.

Is there anything I can do about it?

Thanks!!

 

[Guest]

Where is your pH at? Pebble pools tend to require more acid, and will grow black algae "easier" if the pH stays high for a while.

The pool I built down your way a couple years ago has the same problem (it is a PebbleTec pool) and they have had good success controlling it by keeping the pH on the low side and not letting it creep up. That should work for you as well.

 

[JasonLion]

There is no easy way to get rid of black algae. Some people have had some success by power washing the pool while it was full of water at mustard algae shock level, though that, like everything else, is not totally reliable.

 

[HardTrance9]

Ok I see.

The pH level is always controlled at 7.5.

Well.. guess there is no much to do then

At least is controlled, but don't like the fact on having this "guest" around hiding in some places..

Thanks as always!

 

[duraleigh]

HT9,

How are you, old friend? You must be maintaining your pools very well now because we haven't heard from you in a long time.....you have become a very accomplished pool chemist. :lol: :lol:

What struck me when I read this is to elevate your FC to perhaps dramatic levels. (40-50)

What is the current CYA for that pool? Chlorine ALWAYS kills algae. YOu have to figure out a way to get it where the algae is (increase the ppm) and make sure the CYA is making it ineffective.

 

[HardTrance9]

HT9,

How are you, old friend? You must be maintaining your pools very well now because we haven't heard from you in a long time.....you have become a very accomplished pool chemist. :lol: :lol:

What struck me when I read this is to elevate your FC to perhaps dramatic levels. (40-50)

What is the current CYA for that pool? Chlorine ALWAYS kills algae. YOu have to figure out a way to get it where the algae is (increase the ppm) and make sure the CYA is making it ineffective.

Hello Duraleigh,

Yes now I get lost from time to time and hardly need to pray to the Gods here hehe. You all have helped me alot and yes, we have being able to maintain properly the pools so far.

Yes I guess that after the hurricane season we might try to increase even more the FC levels. CYA is at 60, so we will try go beyond the shock level in some 5-6 weeks.