1st moe is right about wrapping with tape to keep the light out. This will stop the algae, no H2O2 necessary.
Proper ph in straight perlite is 5.5 to 6.0, and you do need a little cal/mag, hope you can get some soon. Not alot just 1 to 2 ml/gal since your are using ro in straight perlite.
Next I wouldn't mix the bloom with the grow nutes at this time, just stick with the grow.
If you want to simplify your seed starts, I can recommend to just start them in a small 2" soil container, and let them grow some roots without the need for nutes through this phase. Then drop them into the hempy. The soil will not effect the workings of the hempy.
Like your vids, very informative, keep it up.