I thought the Lucas was the three part liquid. Grow, bloom, and micro but it might be something else. Maxi crop is a complete two part dry nute line from GH. Just make sure to do a half and half blend of grow and bloom during early bloom. Many people want to take the nitrogen away before she has finished growing in stature. I do use a TDS meter. I prefer a reading of 1100 for most of the grow. Starting with a 440 or so for my hard SoCal water. I used to use reverse osmosis water exclusively, but when I tried tap water I had better results. I also think all the extra calcium helps the plant. I use pure 85% phosphoric acid for ph down. That is a chelate, it will break the large bonds of calcium down into absorb-able sizes. Ph pens are a no go for me. They do not hold calibration enough for me to trust the readings, so I stick with the old reliable ph drops that change color. Ph pens can give you a different reading every time you check a solution in a one hour span.