This whole PH thing is driving me crazy… Last week when I added nutrient and adjusted my PH to around 6.4, I measured the runoff and it was low (5.6-5.8). I used distilled water at that time. I want to be able to use tap water but I see we have chloramine in our supply, higher levels too 3-4.7ppm. I purchase an online filter to add to my hose and filtered some water last night. I was surprised by how high the water PH was after filtering. This morning I double checked everything and this is what I found. Is this at all surprising to any of you?
I performed a slurry test using 1c Happy Frog + 1c filtered tap water (8.9) - finished PH is 6.1 (no picture, sorry)
*Raw tap water PH 7.2
*Tap water / Filtered (inline chlorine/chloramine) PH 8.9
The reason it is frustrating is because you cannot pH distilled water. Distilled water has no pH and should not be adjusted. A pH exists in water due to ions present. Distilled water has no ions present for a pH to even exist.
A low runoff pH is usually associated with a mineral salt buildup in your soil. Happy Frog will revert to a pH of ~6.5 with a good flush down to a runoff PPM of 300 to 400.
Also the reason your filtered tap water is so high is the removal of chlorine/chloramine which is acidic. Its the mildly acidic nature of those chemicals that kills bacteria. Once removed the leftover minerals that survive filtering are more alkaline. Adjusting with pH Down, which is just Phosphoric Acid a food grade acidifier, will bring it back down to where you want. For my tap water it only takes a few drops to adjust a gallon.
Thank you for the explanation. That said, when I flush. Do I flush with my filtered tap water (ph 8.9), or adjust the PH down to the 6.5 range and then flush?
It’s best to flush with RO or distilled. No pH adjustment necessary. Stop flushing when runoff PPM is < 400 and the pH will have been corrected automatically, as what you are doing you is washing out the acidic mineral salts.
A flushing product like Floraklenn or Sleggehammer will make the process go more quickly.
There is no need to flush if the pH is already ~6.5.
As far as flushing, what I meant is since my filtered tap water is 8.9, do I adjust that down to 6.5-7.0 before I flush the plants. Or, does it have to be distilled (don’t have RO/DI filter)
It doesn’t have to be, but it would be more effective. Yes, if you are using tap, then pH it to 6.5 and flush until PPM is <400. It should correct the soil back to 6.5, as you will have flushed out the acidic mineral salts.
With a tap water source at 7.2 I would use this versus filtering. My tap water source is also 7.2 with a TDS of 140. Admittedly I don’t gas off the chlorine or Chloramine either and have done well
It can in above normal concentrations, most cultivators let their tap water supply set out over night to gas off. I generally don’t have that kind of time and have been successful with plain old tap water with all its additives. Stop by my journal sometime, I’m far from being an expert grower and consider myself a hobby grower. I’ll tag you if you’re interested
