Roots dont look bad,Do not run H202 at ALL in your system.That shit is bad man,It kills off everything but also creates the perfect environment for explosive bacterial growth after it leaves the system.I only use a small drop in seed starting water to keep seeds from hardening off when transplanted.I would not change the res on sunday.Leave the
hydroguard in there to build there army.In a few days your gonna see root growth like youve never seen.I would wait 10 days before you change the water.If you have tanks to store the water in its best to get your
hydroguard in there a couple days before and aerate the water with an aquarium pump.
Thats what i use in my top off reservoir and it stays crystal clean.Looks like you got past the first step of taking some solid advice,Congrats.The rest is easy