PH Down ??

[GpsFrontier]

So does that mean i'll need to add any nutes or just leave it alone and add my PH balanced water and just take notes?

I think you said you had a 45 gallon reservoir, filled to 30 gallons. If so, you could add 15 gallons more of nutrient solution without buying a new reservoir, and that would increase your water volume (to plant ratio) by 1/3. That would give you 4.5 gallons of nutrient solution per plant. That would definitely be more in line with the water volume I would want to use for large plants like tomato plants.

P.S.
Now you can see why even though I like the GH flora series nutrients, I needed a cheaper alternative.

But as to your question, you could really go two different ways with it. First, you could add the extra 15 gallons and continue taking the notes as mentioned using a 45 gallon reservoir. Or if you really wanted the learning experience. You could leave it at the 30 gallons for now (which I assume is about what you've been using), and take the notes as described. Then with the next nutrient change, up the water volume (nutrient solution volume) to the 45 gallon mark, and continue taking your notes through that nutrient solution cycle as well (keeping separate logs for the 30, and then 45 gallon reservoirs of course). Then you have first hand data on of both water volumes to compare results with. The second option is more work, and not a quick fix. But the first hand learning experience could be very beneficial to you for your next grows. So it's really up to you if you want to use these plants as test subjects for data collecting or not.

To be honest I used to write everything down at first myself (excluding EC/TDS/PPM because I don't have the meters). I wrote things down like when I do nutrient changes, water volume, pH, water temp (when I got a thermometer for it), if I add any additives like H2O2 or compost tea etc. etc.. And I keep a close eye on my plants along the way, looking for leaf color like a nice dark green for healthy plants, or any discoloration that would be signs of nutrient deficiencies or toxicities. Also looking for things like soft or firm fruit, quick or slow plant growth, and even pests that would be affecting my plant health as well.

But over time I've gotten lazy. Even though I still constantly observe my plants looking for any signs of something wrong, I began forgetting to write down things like when I did a nutrient change etc.. And as I've been trying to say, you just cant compare "non-constant" and sporadic data and expect to get accurate comparisons. So I just stopped writing things down. But one of these days I'll create a chart for all the variables that I can easily write it all down (without going through a sheet of paper every day). Now that you have me thinking about it, I'm putting it on my "to-do" list. Yes, I actually have a real one, it's to keep track of things I need to get done for the herb production greenhouse. It's work, but I'll need to keep track of all the variables of the herb production systems to be as productive as I can.