The Hydroponics Blog

Changing your fluids is paramount.  In NFT hydroponic systems, we’re talking every 7 days.  But for purists, try every 24-48 hours.  Does this yield results?  Yes, if you have every other factor right such as temp, humidity, correct light wattage and genetics.

Hydroponics is something that you either score 3/10 or 10/10.  Every factor correct, kaboom, monster flowers.

Pebble/bucket systems seem to survive the fluid better, although pH can rise dramatically so daily adjustment required.

If you have all the time in the world, I would change nutrient every 48 hours, assuming you have the perfect hydroponics setup.

Otherwise, every 7 days is fine.  pH adjustment daily for pebble systems (or wash the pebbles for 30 minutes continous to reduce this problem).  NFT seems to hold pH very well, so no adjustment needed.