Was chatting with @Hanuman today and he has sent an email to Dennerle to confirm the [PO4] in theirs products
But their S7/E15/E30 system is a bit complex IMO
S7 you dose 3ml/100l every 7 days
E15 you dose one tablet/100l on 15th of month
V30 you dose 3ml/l00l on 30th of month
Sounds a bit crazy. Unless the ingredients are obviously incompatible I would just divide by 7 for S7 and 30 for the others and dose daily...