For my next grow I will be using an R/O filter. I hear everyone say they use it and the water where I'm at is not great. So I got one. I haven't installed it yet, but that's OK. It's for the next grow.
I also picked up the TPS nutrient line. I'll be following their instructions.
In the instructions, it says that R/O water needs a ph buffer. I dont really know what that means. A brief explanation would be nice.
What is it meant to do? Is using calmag
like normal enough of a buffer? Should I use ph up and down to create a buffer before adding nutrients like it the instructions say to do?
If anyone is familiar (yeah, you) please say what you know about the R/O water or TPS nutrients.
PURE water (distilled) will have a neutral pH of 7.0. However, RO water isn't pure, it may/will have a few molecules of something in it that will affect pH. My tap water (Phoenix) is horrendously hard, with a pH of about 8. That alkalinity comes from calcium carbonate, mostly, and it is intentional in a city water supply. You need to buffer the water with something alkaline to prevent the water from getting acidic and dissolving pipes.
If you have just a few molecules in pure water, it will swing the pH, but it has no real buffering capacity, so anything you add could swing pH wildly in one direction or another. Since nutrients usually affect pH, you need to mix everything together and then measure/adjust pH at the end. Makes no sense to dump pH Down into your tank to neutralize the water's alkalinity, then add a bunch of nutes that do the same thing, then have to add pH Up at the end to fix it.
There is an recommended order of mixing things so that the nutes don't act on each other and lock things out. One rule: Always add your nutes to the water. Do not mix nutes together and then add that to water.
If using Silica, always start with that and leave it for 10-60 minutes to 'bond with the water' before adding anything else next. (The time values vary with the source, but you do need to wait. I wait 1 hour just to be sure). Next, if using cal/mag, add it now. Third, add your nutes, then your additives. pH at this point. All your buffering nutes will be in and interacted to give you a starting pH to adjust. If using H2O2, add it last.
pH pens, the cheap ones, are notoriously inaccurate, but at least one could get pH to be consistent, which is important. Also, pH is less important if growing in soil as the soil will buffer the pH to some value anyway.