This is a very complex reaction due to the presence of Borate which can make a variety of resultant anions. Don't worry about it. It is difficult for met to solve. I like easier equations. You are coloser, but the mixture will contain Ascorbates, Borates, Metaborates and the PG even makes some salts and esters with the materials present. You see, the Boric Acid will react with some of the metaborate and also with the OH ion present (being alkaline).

Just measure the pH and be reassured that if you adjust it to where you want it to be, things should work out.

Don't forget the toxicity of Boron containing salts to Citrus plants. IDK where you are located, but some of these salts are restricted in CA and FL.