I would strongly recommend you not use Fox Farm nutes, or any nute that has any organic components in it, in hydro .
Im not talking organic as in health food. I mean anything derived or made from anything plant or animal based. That includes things like kelp, worm castings, enzymes etc etc.
Also, check any additives carefully. Some calmag mixes have organic components as do some bloom boosters, PK additives, and all the rest. Im not a big fan of additives, bloom boosters, etc anyway. They are mostly snake oil intended to bleed insecure growers out of their $$, but thats just my opinion.
The problem is bad bacteria, algae, etc just love the crap out of anything organically based and will grow like mad in a hydro enviroment with organic nutes.
There are several choices for pure mineral based nutes, but I happen to like Jacks 312 hydro. Its pretty much the cheapest nute out there, easy to mix up, and its been around forever - including being one of the leading commercial nutes used world wide. Its well proven in and out of pot growing. Jacks is a 3 part powder mix, but there are also concentrated pre-mixed liquid nutes that are safe. General Hydroponics has some, but you will find all the liquid versions are far far more expensive to use. They are essentially taking the same ingredients in jacks, putting it in a bottle and charging you 20 times as much per gallon of rez you need to mix up.
Possibly the single biggest key to successful DWC - or any form of hydro actually - is water temperature control. Bacteria grow like mad in warmer water. If at all possible, try to keep your water temps below 70F. If you cant, then you need to run a sterile rez. Some people have success with benificial bacteria, but not when the temps get too hi. I personally have had zero success with bennies.
Best hydro PH is in the range of 5.5-6.1. It will vary some with the strain, but I shoot for an average of 5.8. I actually start my rez around 5.6 and let it drift slowly up to 6 then go back down when I do a rez re-fill. How that works for you will depend to a large degree on your water and it's calcium hardness. In addition to calcium hardness, bacterial load will also drive up PH. Things like root exhudates and to some degree the type of nutes you are using can drive the PH either way.
Proper EC levels will vary depending on the strain and the age of the plants. There is no best EC. You need to let the plants tell you what they want. I recommend you start out low with new seedlings. Maybe 100-200 PPM (500 scale) or 0.2 - 0.4 EC over what ever your water starts out at. If your water starts at 0.3 EC, then add nutes till its at 0.4 EC, or what ever your target is. Then just watch the leaves. If they are too pale, increase the EC in slow steps. If they are too dark or the tips are burning, drop it a bit. Every strain is different.
If you are growing several different strains in the same system, then you may have to split the difference.
Welcome to the joys of hydro growing! I hope your grow are fantastic