The old yellowing leaves question.

Well I’ve been all over forums and further over the past day or so and come up with anything from nitrogen deficiency to cold soil. Seems everyone has an opinion so I’m going to ask you guys for a shot. 6/7 weeks in, I’m in bat special mixed with biobizz light mix and using biobizz grow/bloom with added cal mag in small doses. Added some Biosys Ecothrive every week or so and even chucked some coffee grounds in for good measure. Don’t think I’m over watering, 12ltr fabric pots and it drinks about 3l per day which I give in two doses. I want to catch this early as I had a similar issue with my previous plant and I couldn’t stop it proceeding upward.
Big Bang Auto.
Temp 25-27
Mars hydro 1000 on full.
Tap water always ph’ed to 6.5 and conditioned with conditioner.
Also sprayed leaves with Epsom salts.

I think a nitrogen deficiency is unlikely at this stage. You may cause more damage trying to correct this without more info. Your best bet might be just to keep an eye on it. Simplest thing might be to recalibrate your pH meter and make sure your pH is good. Could be a little too low.

Thanks I’ll take this on board.