I've not used a hydro cloner before so can not comment truly on the matter...
But ya certainly don't need any nutrients in the reserva for cloning but at best foliar feed every couple of days., reserva should be around 18c to 21c.
Now i'm a bit more familar with just ol cuttings 'n' rooting plugs & only used root roit cubes 'n' jiffy pellets before...
My best results are with a heated propargator with temps maintain to 26c to 32c on average & high humidity 24/7, keep the plugs moist as clones don't like dry plugs/cubes ! with a folair feed every couple of days allowing to breath for 1 hour every day by removing humidity dome.
All should root with in 10 to 14 days.
Now i don't like 24/7 lighting as plants need a dark period for doing hormone stuff using a 18/6 light regime as standard - i use 16/8 for rooting clones/veg but thats just me as i don't like giving Mr electric bill man more than he deserves... rofl
You can leave them in an unheated propargator tho but rooting takes longer plus some failure of clones may root from 10 to 21 days.
Clonex is a good rooting hormone gel