New grower in need of advice or suggestions

Good morning, new here just got into growing pardon my randomness not good at these things

My current setup consist of:
Vivosun 3x3 tent
Vivosun 4" fan kit
Vivosun 2"x4" stones x2
Two five gallon buckets dwc
Vivosun 32w air pump
Viparspectra p2000
Vivosun ppm and ph pen(plan on upgrading)
Base ph tested was at 8.0 tap water
Base ppm was 138
Strain of choice is grand daddy purple (GDP)
Nutes are gh performance pack,hydraguard and calimagic

Going to be using oasis cubes as medium then transplant into dwc I’ve started two and failed on one, it germinated then sprouted it and it fell over and i accidentally pulled it’s shell off and its starting to brown im assuming it’s gonna die so im going to start a new one and the other is going but it doesn’t look promising has fuzz on it’s stem im assuming it’s mold from over watering and no air flow. Any advice would be much helpful or suggestions to help be successful

Rock wool is tough to use properly: soak in PH adjusted water then squeeze out almost all of the water. Split lengthwise so can inspect root growth.

Germinate seeds in a 1/4 cup of distilled water with 1/2 tsp of peroxide in it, cup placed in a warm dark location until seed cracks. Place in rooter and dome it. You might even consider placing in a Solo cup or other means to keep under a dome and the only water is misted on the dome. Once a taproot pokes out of the bottom you can place into net pot with hydroton. You will be top-feeding until tap root reaches nutrients. Liquid needs to be 1 1/2 to 2" below net pot with vigorous air movement.

The problem you are going to find out with DWC is that in mid flower when plants are drinking a gallon or more a day, you will be filling buckets twice a day until harvest. PH will also be a major issue as nutrient solution changes throughout the day. Better to set up an RDWC system that will maintain levels and offer you the ability to maintain solution temps under 70F.