Hi guys. Im off to Amsterdam for New Years for 5 days, can't wait! But my plants need daily feeds and ive got no one to care for them. Ive seen some cheap irrigation systems, but I seem to have Ph drift with my tap water/nutrient combo. Will I need a (expensive) Ph controller? Or will my Ph stay stable if I switch to RO water? Im using floranova bloom and top feeding rock wool currently with decent results. As an example, I had 6.5 ph water - ph down it to 5.8 and by this evening it had crept up to 7! Higher than before. Not sure whether it's a ph meter issue or the mix buffering upwards? Regardless I don't trust putting a reservoir of water in without knowing the ph will stay stable. I have until the 28th of December to find a solution! Appreciate your help.