H2O2 root drench for gnats

[Virgin Ground]

4:1 water to h2o2. Is this the correct strength? I noticed some gnats and want to do a root drench. They are clones in solo cups.How long should I let them recover before I up pot them. Should I perform more than one drench?

I appreciate the assistance.

 

[Virgin Ground]

Also, would watering from the bottom help?