Black Algae on Newly Re-marbelited Pool

We have been left with Black Algae marks all over the newly marbelited pool, due to a number of long delays between various jobs on our pool system. We are extremely disappointed with how we have been treated, given that we stuck with these guys through multiple problems and issues they had with a ****** phone, and both trucks breaking down! It seems like another example of once they have your money, you are no longer a priority! We had them re-marbelite our pool and they finished on the 23rd Jan 2026. We then had to wait until 2nd Feb before we could activate the Kreepy and add the chemicals. Also on the 4th Feb, we had to report that the pool light they fitted was faulty (even after multiple calls and messages to them, this wasn't changed until 16th March). Soon after we reported that the Kreepy wasn't working, because there didn't seem to be enough pressure. Long story short, they advised that we change the pool pump and filter sand, which they eventually did on the 24th March. I was asked to report back after a day or so of running and I informed them that this still hadn't worked and there still wasn't enough pressure to make the Kreepy work. They then advised that we upgrade our pool pump filter, which we agreed to. After further delays, they eventually fitted it on the 10th April. This then allowed enough pressure to make the Kreepy work, however, due to the numerous delays, the newly marbelited pool had developed dark marks all over. The co-owner said that he would make sure he sorted this out with chemicals. Then they went silent again, and we eventually got a voice message on the 26th June to say that after having someone review the photos we sent of the marks, it was confirmed it was Black Algae and this is notoriously difficult to remove! He then went on to say that we wouldn't have had this issue, if we had chosen to have them install a fibreglass pool, instead of choosing to have our pool re-marbelited! In other words, he was looking to blame our choice of pool refurb, rather than the multiple delays which was the exact cause of the issue. I sent him another voice message on 14th July, asking him to call me to discuss and I have not heard anything from them since, it actually looks like he hasn't even listened to the message. So there you have an account of our experience, I leave it to you to make your own minds up.