Is it nessary to start seeds in hydrophonic medium

A customer has a question and I hope we can get some opinions on it, thanks

definepurifiedwater is it nessary tostart seeds in hydrophonic medium what is rooting solution what causes browning of outer edges of lower broad leaves using 45 watt led light ten inches away 22 hours a day thanks patchas

Purified water simply means filtered or distilled to remove minerals and chemicals that may be present, is it absolutely needed for hydro not always depends on quality of your water? Most used filtered water because anything in it is only what they add