Vivian, welcome to the forum !!
I took a quick look at your posts and found out that you have a concrete pool, that's why your brushes keep falling apart. Get yourself a wire brush and you'll get much better 'life' out of it. The plaster surface is too hard/ rough for the nylon bristles to handle, I find it hard to believe that the pool builder gave you a nylon brush for your pool
I wish you well with your pool, if you have any more questions - just ask - again, welcome to the forum - Waste
Bookmarks