HELP! PH problems

[jiggeryqua]

Hi - first post, so hello forum! First grow, too, and it's not going so well. I think I have my growing medium right, and my set up right. It's getting biobizz according to their schedule, along with 1ml of cal/mag. But it's struggled so far - symptoms that led me to invest in a ph meter.

I calibrated the meter correctly, and it seems reliable enough most of the time. I filter rainwater, which with the nutrients reads as 7.9-8.2 So I drip some PH down in, check again - watch the PH drop marginally for each drop, down to 6.9-7.1. I'm aiming for 6-6.5, as I understand it. But one more tiny drop of PH down and the meter tells me it's 4-4.5. Every time. Is it a meter problem? I have PH down, but I've spent entire evenings bouncing around trying to get an ideal PH. Sometimes she gets watered at 6.9, a couple of times I chanced the 4.5.

Either way, it's an unhappy plant with little growth, most of the leaves having some yellowing, some of the leaves have been discarded by the plant.

I've done some research, so think I'm correct in identifying this as a PH problem, but don't know whether I've got a duff meter or if I'm misunderstanding some crucial part of the process?

Thanks in advance

[9fingerleafs]

that means the water with nutrients you are adjusting the ph of is very weak in concentration, doesnt mean you need more nutrients its just ph down is too concentrated for you. try this, you already kinda know how much ph down you need (drops) so take a cup of water and dissolve those few drops of ph down in it, then with a syringe add to your nutrient solutions slowly, now it will be easier to reach that desired 6.5 and you can store that diluted ph down and use it later

[HappyDaze]

I've never used biobizz nutes, but you're probably wreaking the organic balance by adding phos acid to your water. I use unadjusted RO with G.H. organics line with relative success. Organics are supposed to be self balancing when it comes to pH. Having said that, what's your grow media? Coco? Soil? Super Soil?

Don't love 'em to death.