How to change water ph on the go?

Hi @Chimken .In order not to have a large PH variation for your plants, it is better to start putting the water little by little, but before that, adjust the PH of the new water. After we have added all the products we want to the water, we should let the solution rest, and then measure the pH. If the pH is above the desired value, we should add to the water a product to lower the pH, which can be solid (powdered), or liquid, usually made with nitric or phosphoric acid. It is called pH Down. If the pH is below the desired value, we should add a product to raise the pH, the so-called pH Up, usually based on potassium hydroxide. The pH Up can also be very useful in case we accidentally lower the pH value of the solution too much with the pH Down. To lower the pH of the nutrient solution you need an acid, use lemon juice. You should add a few drops of lemon, little at a time, and measure the pH of the nutrient solution until you get the desired result. You can also use vinegar. Vinegar is also an acid and will lower the PH of your nutrient solution. Another solution is cream of tartar, also called potassium bitartrate or hydrogen potassium tartrate. Potassium bitartrate crystals are not harmful to health and, if ingested, do not pose any risk. Good luck mate