Alde offers it's own antifreeze, a premixed glycol liquid for use down to -37°C. 
 
Alde's ready mixed premium quality glycol for Alde heating systems has a lot of benefits:
 
-Long life protection - 5 years
-The glycol creates a long protective layer for the heating boiler and aluminium tubes inside
-No gel formation or separation
-Environmentally friendly
 
The average UK caravan needs 8-12 litres of fluid for a full flush. 
 
The average UK motorhome needs 10-15 litres. 
 
Alde do not recommend using automotive glycol as this contains incorrect additives and can corrode your system.