Im running a 20 gallon rdwc system and after adding in nutes it won't seem to drop ph. Its stuck at 7.0-7.4. Wondering if its some sort of buffer in the nutes. Im running Masteblend 3 part salts. Tried a new bottle of ph down and still nothing. Any thoughts?
Running tap btw until RO filters come in (240ppm)
That’s too high for hydro.
I’d do a couple experiments to figure things out while you wait. Grab a good size container like a 1 gal cool aid jar. Fill it with a measured amount of tap water I’ll assume 1 gal.
Measure ph
While stirring add ph down until you get to 5.8. How much did you use?
Repeat this with the same amount of res water.
Now you know if it is your nutes or supply that is the issue.
You can dump that ph’ed water back in and now you can calculate how much ph down you will need for the system. Post that info up and I’ll let you know if this is normal or next steps.