Hi there - new here! You seem a friendly bunch so I'm hoping someone might be able to help with a little guidance on a couple of issues ...
A bit of background. What I have is more of a water feature than a swimming pool - 10,000 litres (2,600 US gallons) and approx 50cm (1'8") deep. It was a concrete construction, then rendered and finally finished with dark blue GRP. It originally had an eco pump and filter (non-chlorine) which was a bad idea. It worked for a bit but then I was away for a few months at a time and things ended up out of balance and algae took hold. Most could be hoovered off the bottom but some stuck hard and would not budge. It could be brushed off with a stiff brush but took ages and only tiny areas could be done at a time. The hard algae has spread to cover quite a lot of the bottom of the pool.
I've now switched to chlorine and swapped the eco filter and pump for a small swimming pool pump and sand filter. It is working well but I had thought (and was told) that the algae which has stuck to the GRP liner would 'die and come unstuck' so could be removed. This hasn't happened so I'm wondering whether there is another way to get this stuff off?
The second issue is around the water line where there are also hard deposits. Not sure whether this is the same issue. The sides seem to have less of an issue with the hard algae so I'm wondering whether this is down to the hard water which we have here?
Here are today's measurements from the test kit I have, which uses the following:
pH (Phenol Red) - 7.4
Alkalinity mg/l (Alkatest) - 250
Cl/Br mg/l (DPD) - 5.0
Hope this makes sense. I've attached a photo in case that helps. I'm in the UK, by the way, in case that matters. Any help greatly appreciated.
A bit of background. What I have is more of a water feature than a swimming pool - 10,000 litres (2,600 US gallons) and approx 50cm (1'8") deep. It was a concrete construction, then rendered and finally finished with dark blue GRP. It originally had an eco pump and filter (non-chlorine) which was a bad idea. It worked for a bit but then I was away for a few months at a time and things ended up out of balance and algae took hold. Most could be hoovered off the bottom but some stuck hard and would not budge. It could be brushed off with a stiff brush but took ages and only tiny areas could be done at a time. The hard algae has spread to cover quite a lot of the bottom of the pool.
I've now switched to chlorine and swapped the eco filter and pump for a small swimming pool pump and sand filter. It is working well but I had thought (and was told) that the algae which has stuck to the GRP liner would 'die and come unstuck' so could be removed. This hasn't happened so I'm wondering whether there is another way to get this stuff off?
The second issue is around the water line where there are also hard deposits. Not sure whether this is the same issue. The sides seem to have less of an issue with the hard algae so I'm wondering whether this is down to the hard water which we have here?
Here are today's measurements from the test kit I have, which uses the following:
pH (Phenol Red) - 7.4
Alkalinity mg/l (Alkatest) - 250
Cl/Br mg/l (DPD) - 5.0
Hope this makes sense. I've attached a photo in case that helps. I'm in the UK, by the way, in case that matters. Any help greatly appreciated.
Thanks - I'll need to try and find one with UK delivery.