Tylo STELLA 2900 3005 Guide D'installation/Mode D'emploi page 31

Regularly descale the tank manually according to the table below. The steam generator will not be damaged by frequent descaling.
In fact, one time too often is better than not frequently enough.
Tylö Solvent
(number of
kW
bags) Item
No. 90903000
2,2-4,5 1
Table 3 Rules for descaling
*It is not recommended to operate the appliance using water of this hardness
Take care during the descaling process and only use descaling agent as indicated in Table 3.
Operating time in hours before descaling
Tylö liquid
descaling
Softened
agent (ml)
water
Item No.
90903002
0-1°dH
250 100
Operating hours at different water hardnesses
Very soft Soft water Medium hard
water
0-3°dH 4-7°dH
60 50
Hard water
water
7-14°dH 14-21°dH
40 *
29
Very hard
water
>21°dH
*