Will black algae grow THROUGH new pool surface?

[1ginger1]

We have a 40,000 gal. in ground pool. In the past 25 yrs. we have had it resurfaced 3 times, about every 7 yrs. . Two years ago we got a terrible infestation of black algae. We spent $100's dollars and back pain. emptied the pool twice and scrubbed our fingers raw. June 2014 we had it resurfaced again ($3300.) We were so worried that we questioned many times if they would be able to remove all the black algae spores? They said yes. They water blasted (the pool was sand blasted before). They put on what looked like two coats of plaster in one day and started filling the same day (took a week before with 3 coats). We were again assured that the black algae was gone and we would have a pool surface that would last for years. They seem to be a reputable company. HOWEVER 9 months and we have black algae in the same areas as before, not as much yet of course. We have been very careful with the chemicals and PH. CAN BLACK ALGAE GROW THROUGH NEW PLASTER? We sent the company a letter of complaint and received back a phone call that said we are to blame. They will not take any responsibility for this. Is there anyway to prove that they were lax in how they surfaced the pool? We are devastated. I haven't been able to find anything online that says black algae can grow from inside out.

 

[Patrick_B]

Welcome to TFP!

I do not believe it's possible for BA to grow through new plaster. Typically, it appears in pools with frequent, and or chronic algae problems. Have you had what would fit either of these descriptions? I'm not trying to be critical, or harsh but this is what is most typical. How are you testing, and where do you usually hold your Cya, and Free Chlorine levels?

 

[1ginger1]

As I said, it started two years ago. Up until then there was no problem. We keep enough chlorine in that we don't have green algae. I will have to look up to see what CYA means. We have had a pool since 1990 and seemed to keep it clear all this time. We have very high calcium in our water so fight with having to add acid frequently to keep the PH out of the pink/purple area. We pretty much test daily. The chlorine is kept at around 7ppm. We have 3 full floats. The temp. has been in the 103-108 area so we must shock a couple times a week. There are around 20 swimming around 3 times a week I have copied off this websites suggestions for working with BA. We spent hoards of dollars for Algecide before. Never helped. Guess we go back to scrubbing. We are too old for this, sigh

 

[Patrick_B]

No, you don't have to do that. Since you aren't familiar with Cya, it's very possible, and likely you have too much. If you do, it's the same as not having enough Chlorine in the water. Cya is a buffer, and shield for Chlorine. A shield that protects it from the Sun so that UV Rays, don't destroy all you put in. If the Chlorine isn't in correct proportion to the Cya meaning high enough, that condition will let all forms of Algae grow. Just to double check, can you disturb this and get a green smudge, or better yet, remove even a tiny piece and rub it on something to see if you get the same result? Can you do that and confirm the results? Work with us here, and we can show you a better way that won't include Algacides, or scrubbing your life away. Start with the ABCs in Pool School, and then recommend chemicals. The Cya/Free Chlorine ratio is critical, and could be the root of all your troubles. Ask questions if you have them and we can help.

 

[1ginger1]

WOW, this forum and Moderator is amazing. We are 78 yrs. old and your help is so appreciated. Yes, the black spots are 'green'. I have printed almost everything off the pool school from Getting Started to the bottom. We are learning about the CYA/FC. We had never added anything over the years but chlorine and checked that and the PH. Then 3 yrs. ago all (you know what) broke lose and has evidently not stopped, had to smile--the H word seems to be a curse word, guess this is a Christian forum (smile). I sent my husband for Algecide with copper. He metal brush scrubbed the spots this AM and added shock/SLAM? (I'm not sure I understand the difference) above the area. Guess now I will wait until I hear more from you. This is so exciting to be able to get help. That doesn't happen much for free. From further reading on the forums I am getting the idea that we need to get a different test kit. We have the basic 5. So we need to go to the hardware and find one that says Cya on it?