Hi there, I have posted this in the invert column as well but as it is about water being too soft, I thought I could get some advice here too. I have apple snails and if the water is too soft, I live in Scotland the ph is 6.6, the shells get corroded. I have put in coral sand but that hasn't raised the ph. I have also started using the additive PH7 but that doesn't seem to be working either, the ph is till the same. I have a charcoal filter as part of my filter system so could this be leaching the properties of the PH7 additive. If anyone can give me advice on filters or products, I would be most grateful. Cheers Xanthe