A:Answer 1. Descaling does need to be done, but the frequency would depend upon the hardness of your tap water -- which I would HIGHLY suggest you filter before filling the reservoir. (You program the machine based upon your home's water softness so that it will let you know when it's time.) The machine comes new with a dose of the DeLonghi descaling solution which you can purchase more online for future cleanings. It must be pretty harsh/acidic because it says not to get it on your clothes. I've also seen videos of people using white vinegar, so you might check that out. 2. You shouldn't get any algae growth with filtered water. The reservoir is at the back of the machine -- but it is clear. Just keep it out of direct sunlight and you should be fine.