u/OwnSyrup6760

Help from the experts would be appreciated since I’m a fan of sanseveria but a novice in their care. I have this whale tail that is fairly new from the garden center, it hasn’t been exposed to any pets that may have caused damage. It’s been watered once in about a month and a half, it sits in a sunny window.

I’ve noticed these spots and rust looking spots on the leaves. If these are indicative of disease, what measures should be taken to stop the spread. Could it also be too much or too little water causing rot or rust, should I use filtered water?

Any guidance on care and treatment products (if any) will be very much appreciated!