Cannot lower pH after using new nutrient solution

[DexterC]

Hello growers,

Today it's feeding day. It's week 4 of flower and I just got a new bloom nutrient with a 4-7-6 NPK ratio, some 1% natural algae extract + micronutrients. So I mixed it with water until I got the PPM around 1200 and it's current pH is around 7.5. I want it down to about 6.7 - 6.8 since I grow in soil so I used the usual pH Down solution I am always using (81% Phosphoric acid), diluted a pipette drop in few ml of water and added 2 drops of the diluted solution in my nutrient solution but pH keeps at exactly 7.5, no matter how many drops I add. I even tried a bit (less than a drop of pipette, just a sprinkle) of undiluted pH down solution straight in my nutrient solution, still 7.5.

I assumed my pH test pen died, but I tried some water in a cup with the same diluted pH down solution I described above and pH went down as usual so I doubt my pH pen is the issue here.

All I am left with is that there may be something in my nutrient solution that buffers the pH, possibly some kind of bacteria which would mean that this is a liquid organic nutrient, not a chemical one. If so, then my questions are:

1) Is it pointless to try to adjust pH here since it will be buffered back to 7.5 or I need something organic to actually lower pH, or that will be pointless too and will be raised again to 7.5?
2) Since I used a strong chemical acid on a nutrient solution that may contain a lot of bacteria, did that harm them and should I change the solution before feeding or will this one work fine?
3) My current pH is at 6.5 in runoff, if I feed this solution at 7.5 will it cause nutrient uptake issues considering this nutrient solution is organic?

Thanks in advance guys

 

[NOOOBIENOT]

Wow 1200 ppm seems high to me but if it is working stick with it ,don't worry about the bacteria as you only have 4 plus weeks to go till chop ,6.5 is a good run off number you don't have ph water if you use organic nutes the soil and bacteria do it for you

 

[DexterC]

Thanks bro I feed her this much because she is showing signs of deficiencies. I assume it's because I am giving her a lot of light and CO2. Also may be genetics, not sure. But thanks man for everything

 

[Buds Buddy]

Have you tried using Lemon Juice to lower your pH ? Maybe your pH down went bad (if it's possible).

 

[NOOOBIENOT]

I have been using the TNB organic ph adjusters for the last 3-4 weeks and i like them a lot so far , a very tiny pinch of a fine granular powder and i have my numbers in my rez , they work great and easy , but i don't like the price but a 1 lb bag will probably last a year or more , the thing i like is i can fill my rez with my nutes and ph it and come back 4 days later and the ph is still the same they seem to really stabilize the water some how , i am growing in organic soil presently , you only need a tiny tiny pinch of this adjuster so i am sure a bag is gonna last a long time , i was given this for free from my hydro shop and asked to try them out before they inventory it , well this product has me sold - no i don't have a vested interest in the company just looking for simple and effective new products , give them a try you may just like them !