Water without drip tray and descaler

Hello folks
,a Siemens EQ.6 top class is now my own.
So far fully satisfied, a great device.
Now I have a few questions, where your concentrated
knowledge is needed
:1. After rinsing the machine when switching it off, I emptied the drip tray and left it outside (to dry the tray and the remaining moisture inside the machine). During this process I noticed that it continued to drip from the area of the brewhead. I wiped it away and waited. Later there was a puddle again
. Is that normal.
2. the water hardness is normally set to 4. Since a water filter was included, I inserted it and activated it in the appliance. If the water hardness (or softening interruption) is then automatically
adjusted
by the
device.

I still have powder descaler of my DeLonghi. One is Purex based on citric acid and the other is a professional descaler with amidosulfonic acid. Can I

use some

of them

?
3. is cleaning the machine (with tablet) also suggested by this one or does one have to
do
it himself on a regular basis
?