One dropper delivers 8.3ml of water per minute.
With the maximum programme of 20 minutes water delivery every 12 hours, this is 330ml per dropper.

In hot periods (30°C++) in high summer I set it to 20 min every 12 hours, in normal summer to 20' every 24 hours, in the rest of the year less and every 48 hours. 1 dropper/pot is enough for small pots, 2-5 for larger ones (small trees!). On holiday, I use a 200-litre folding bin from Griin as a tank; a portable plastic bin also works well.

I have calculated the water requirement using the following page.
https://www.gardena.com/de...

Example: Irrigation of 5 min / 24h for 10 drippers for 10 days results in 4 litres. That means one dripper delivers 0.04 litres in 5 min per day. This means 0.4 dl.

I use a 30 litre wide-necked barrel from the supermarket as a tank. The current setting is 15 min / 12h.