We have a small swimming pool in our back garden which hasn't been used for years. We have emptied it of the old nasty water and given it a really good clean but there is a build up of lime scale which doesn't want to come of. We have tried supermarket lime scale remover which doesn't seem to be doing the job. I know there are other stronger products on the market but am concerned that the stronger chemicals may damage the liner. Any thoughts or suggestions would be appreciated.