CO2, when understood correctly, can/will add around 20% bigger buds to your harvest. The thing to remember are the things that are highlighted and taught by Nebula and Sirius about CO2. Primarily I run them below the plants to give them light. CO2 loves light heightening a greater photosynthesis process. Started in the 2nd week of flower CO2 actually runs better in a sealed area, as it is a gas, a very dangerous gas, so, sealed area - like the Bloom Box - is ideal. I am able to grow nine plants, and the girls love it.
Also, in a DWC, a product line called CANNA, has the absolute best products - with one of the key features being the self-regulating PH factor. I change water weekly, and once PH is set between 5.2 -6.2, I have found that the plants don’t leave that range all week. Barely, do I have to use the PH gun.
I have switched from 12 products every week down to 4 every week I change water. I use CANNA AQUA, but they do have products for soil - Terra.