Baking soda... It's sodium bicarbonate for ph works well. Also you can buy calcium bicarbonate Which is better because the plants use the calcium (unlike sodium levels we try to keep down) and the bicarbonate acts as a pH up and buffer.
Citric acid buffers poorly and you will need to keep adding non stop. Things like lemon juice vinegar etc. Should not be used for that reason. Phosphoric, sulfuric and nitric acid buffer far better and I would say phosphoric is your best bet for our use. Without getting into the details of why
Products such as calimagic are even more optimal if you are new in order to keep you nutrient ratios balanced. It contains calcium bicarbonate and magnesium sulfate. All num nums to our plants in proper quantities
Are there any natural products I can add to water to lower the ph of my soil it is sitting around 7.7 pushing and closer to 8 at times I am mixing RO water( ph 7.0 )with city tap water (7.5 ph) 50/50 mix and I am using dutch nutes oganic gro 2.5ml/l
Start with 1/2 teaspoon of lemon juice. Dont get more organic that that. Use 1/2 tsp then stir and recheck. As you get closer to your target Ph you can adjust from 1/2 tsp to get where you want to be. :D