Where's the GH Flora Micro that's the base of the trio you need?I hear you, bud. My medium is peat pellets, water source is bottled spring water, added some floragro and floramicro, I have a 20qt basin. I hope that's all correct info you need. If I missed something I'm sorry, still learning.
Listen to @xtsho put them in coco (he's always right LOL). Then buy some GH Flora Micro and use their DTW chart
I'd start at 1/2 of the suggested dose. You need a TDS pen and a pH pen to run hydro, at a minimum.