Something is very wrong with my tank. Please help me

[Dom]

I use only RODI and pre-made salt water from my LFS, which has always worked for me.

Just an FYI: You can not rely on the LFS. If you are buying water from them, what they are selling you is water from their system. They are not selling you freshly mixed water.

They are selling you water from their system which is already depleted of all the important elements that we replenish through water changes. They sell off their old water and then they mix new water to add back to their system.

You already have an RODI system, just mix your own.