Sir, I have an important question. The water in our area is soft/sweet water. We have an RO Machine. Now considering these two facts, is it really necessary to have an external filter? Will not having the external filter damage my machine's internal filters BEFORE one year? Or will it last a year? I change the internal filters every year anyway. So if I don't spent extra on external filters now, and instead run the RO machine directly with brand new internal filters that I will change after one year, will it be a wise decision? The water in our area is soft and sweet.