Yes, I'm using a hydro setup. I started the seeds in rapid rooters and placed them in clean hydroton. I use RO water and GH 3 part, some CalMag+ and my PH doesnt rise, it falls.
Since I started using RO water, I've only hd to use the PH Up. Never the Down.
MisterE Reviewed by MisterE on . PH Dropping quickly? I'm sorry to post this question, I tried to search but the term "PH" is too short for the boards search function... I'm having to PH Up my nutes more frequently as my plants grow. I'm wondering if this is considered normal, or if it is indicitive of any actual problems etc. I only use 8 to 10 gallons or so total (going to change it out and measure carefully today) and the plants are only about 10 inches tall, on their 8th node. I calibrated my continuous meter yesterday, and PH Up'd to Rating: 5