I am about to hope to rule that out now by filling up the pool to a certain mark - and using a photo just in case. I just did that. I have experimented with the Potassium Peroxymonosulfate in several tubs, but I do not Consider I am getting the https://www.profi-poolwelt.de/400-x-125-cm-stahlwandbecken-komplettset.html