We recommend to use PK 13/14 always for one week when you use CANNA nutrients. The CANNA base nutrients already contain sufficient P and K during the rest of the cycle. There is a certain period during the flowering stage though, when we can't increase the feed for the plant any more, so we adjust the PK-ratio by adding PK 13/14 for that one week.

Never use raw rockwool! The pH is too high. Always soak rockwool before using it for the 1st time. Soak with water or a nutrient mixture with the pH adjusted to 5.5 and an EC of about 1.3 mS/cm.