Vergeling van alle bladeren met rood steeltje

Rainwater can be too acidic. Make sure you're checking pH. Bad pH can cause lockouts, explaining the yellowing. The red stems are usually just a sunburn. You can confirm this by checking if the stems are still green on the parts that dont touch light. The yellowing may also be due to you completely phasing out nitrogen or it could be a P/K deficiency. There's a lot of possibilities to be honest, but you would know which is most likely.