Hi Jay,
Are you using Ocean Forest? Or Happy Frog? I used ocean forest for my first grow and, even though I was a noob and did have issues, my grow was quite successful.
Having said this, I am now using my Ocean Forest mixed 2:1 with Promix HP. Promix is an "inert" soil without nutes. I am back into 3 gallon fabric pots and use 2 gallons of Promix and 1 gallon of FF.
I wet my soil well before placing the seeds-tap root facing down (best you can)- then when the surface looks to be dry, I wet only the spot where the seed is with a spray bottle. I may do this twice a day, with only a few sprays at a time.
I usually wait 5-6 days to give the seedlings their first water. It is usually 4-5 days between waterings for the first week or two, then it starts to tick up a bit.
At about 2-2.5 weeks I become more vigilant about making sure I get run off. Especially important with FF.
When using FF you may not need any nutes for 3-5 weeks. Before giving nutes, I run a big watering a few days before the first nutes. I will generally double the amount of water it took to get run off, which for me in a 3 gallon fabric is usually about a quart - so for the "mini flush" before nutes I will run about 1/2 gallon through, let dry a few days then nutes.
These plants really seem to enjoy their dry time, so it is VERY important not to over water.
If PH is an issue, you can add 1 tablespoon of dolomite lime for each gallon of soil before you start your grow. This will help to balance.
Also, Sierra Natural Science and Advanced Nutrients both have nutrients that do not require ph adjustment, this may help as well.
Depending on your calmag, it may be VERY acidic and, unless you get something like Advanced Nutrients cal mag, it will need to be PHd.
CalMag is going to be especially important under LEDs.
This is already a long post, so I will stop here and wait to see other responses.
Welcome to the forum and know you are in good hands. Without the growers on this site, I would have had a very hard time with my grow.