To start off the 3 part formula works best with RO water or tap water with a low ppm under 300 I want to say, maybe a little lower. The Cal Mag should really always be used when using RO water or water with a low PPM, you see the RO process can cause the water to loos some of the natural micro nutrients that are in water that MJ needs and without those micro nutrients MJ can show defs in certain areas and the Cal Mag provides those micro nutes so the plant can still thrive andbe be able to have a healthy life cycle. So the answer is yes the Cal Mag can work in conjunction and I just explained the need for it.
When you say that you don't understand the conversion table, which part are you referring to? The EC, Calculating for advance up types, basic feeding or what. Once you understand the basic idea of veg and flower according to PPM/TDS I think it becomes much easier. As for the Pith, I am not sure that you would need it with the 3 part for the fact that the 3 part has PH buffers that are pretty consistent.
Well, don't feel obligated to try it, just think about it and if it isn't going to be something that makes you or breaks you for some certain reason and you feel comfortable then give it a run.
PS, I am sure that there are some people on here that have exp with it, as a matter of fact I think that Lake Wood or GK use a modified version. Also just like most formulas people have their problems or tweek it a little to fitt their likes, while others just look at it like a god send.
Adieu
BlueBear Reviewed by BlueBear on . The Lucas GH 3 part formula This is for JW and WH and any others who are not familiar with this GH 3 part formula which is a widely used and respected feeding chart for the GH 3 part. From the OG FAQ Reposted by BlueBear Nov 17, 2006 General Hydroponics Flora Series Feeding Strategy - Lucas Formula G-M-B (Grow-Micro-Bloom) 0-5-10 - For Vegetative cycle (18/6) 0-8-16 - For Flowering cycle (12/12) The numbers above indicate the number of milliliters (ml) of Flora Grow, Micro or Bloom formulas that I use in one Rating: 5