First scrog help me out

you don't need "ph-down." Any acid will work as long as it doesn't screw with your fertilizer. white distilled vinegar is a good option. It doesn't add anything as far as extra plant nutes or Na or anything problematic. pH drift is not caused by the acid used.. it is caused by unbuffered solutions. I can add my nutes to anything from 7-8.4, from experience, and it comes out at ~6.0. It is stable and automatically balances out at 6.0 because i buy from a reputable agricultural manufacturer instead of some marijuna brand. they employ chemists and such vs some guy in a garage ignoring all common knowledge that existed before to do it 'their' way, lol. So, if you have problems with pH drifting, blame the fertilizer and not the acid or base used to balance it out. If you look at ingredients of those "ph-down" products, it's just citric acid and a few other options, lol... they are not more "stable" as i often see stated as a reason to overpay for a cheap product wrapped in a brand name for a premium price. H3O+ : OH- ration = pH ... log scale. A weak acid is a weak acid but doesn't cuase greater fluctuation in and of itself. Stability of pH has to do with buffering. If the numbers that make up the ratio explained above are large, it will not shift easily and will dwarf any prior existing ratio, so it calculates out nearly the same no matter what (ph-balanced options do this, assuming they do it "right"). Turns out you can use a ton of shit you learn in school everyday :P pH stability is simply about numbers. 10:1 H3O+:OH- ratio being 6pH with 100:10 vs 100,000:10.000 is much easier to shift. The larger numbers mitigate any small changes to meaningless deviations, where as unbuffered can shift very quickly and for non-drastic reasons.... fyi, the numbers that'd we'd be working with are in moles... 1 mole is 6.022*10^23 atoms or molecules. BIG numbers... 1M HCl is 6.022*10^23 mlecules f hcl dissolved per 1L. HCl disaccociates 100%, so you get 1 mole of H+ looking to bond with h20.. 1M HCl is a strong acid. Probably need 1/t0th of a mL or less per gallon... it won't be any more or less stable if youuse the appropriate amount to balnce your water to your target. but it would add Cl, which isn't great. acetic acid.. no problems. cheap. no less unstable than anything else added that will balance your solution. Anyself-respecting hydro nute that isn't ph-bufferd is trash. for that rereason, and it's not new knowledge... that manufacturer is simply ignorant of common knowledge.

You can try citric acid powder(look for it in the canning section in your grocery store)to get by on but I'd order more pH down stat...citric acid isn't as stable IMO as the actual down and you're gonna get some wild fluctuations in DWC with it.

Buy pH down or using lemon juice can help lower pH. Be cautious with amounts and test regularly for desired PH start with one drop