I have always assumed that because I water with only rain water in the summer and melted snow in the winter I would not have any built up salts. Now that I know that the magnesium sulfate is actually Epsom Salts, I am wondering if that is the salt that can build up. I have a variagated lemon and a Calamondon orange in pots. The Calamondon is currently putting out a bumper crop of buds, but it does have a very yellow tint to the green of the leaves. Do you think it is getting too much salt? The lemon looks very health, but it has never set fruit (4 years). Does the lemon need a second plant for cross polination? Hmmm, that is a lot of questions, isnt it? Well, if you know the answer to one or any of them, I would sincerely appreciate your advice.