No, Don't sprinkle perlite on top of the soil, this will do absolutely nothing to help with the rooot zone being a nice loose air filled soil. Your plants are starving for oxygen at the rootzone.
Ok, I've read your previous threads
http://rollitup.org/t/help-please.942730/
http://rollitup.org/t/leaves-are-starting-to-curl-inwards.942687/
You have to actually do it, not just continue along as you have been.
You have to go buy some soil from a garden centre or some store, you make sure it has perlite white specks in it and ask or just do it, cut open and feel it and make sure it fluffy and soft 10 times airyer and fluffier than what yours was, it must not look and feel like moist shit in your hands and compact! dont buy bag manure cow, sheep, chicken, etc. you want nice fluffy soil. Your marijuana's base to grow in making it feel like it is growing on a hilltop in beautiful outside soil. not growing out of a rock. rock = your soil.
Buy a small bag of more perlite which you will mix in with the big bag of soil.
Get bigger pots that have holes in the bottom.
Now carefully transplant your dying babies into this fresh soil mix in the new pots doing everything with extreme care. (two 'cares' in that sentence!)
1L for those pots you were using before was too much. those size pots with those sized plants would of only needed less than half of 1L every 3-4 days(3-4 days that is if the soil was normal and properly dried as it should.) Do not overwater again now. After you get them in the new pots in the new soil gently water them with 500ml of water each plant in a circle around the pot not in the middle at the stem or leaves. raise the lights a bit because the plants wont be in full light processing mode now and will just be a burden to them. Done. leave them alone for a few days.
I realize you are for real and are having serious plant issues is why I write this and the plants will not survive unless you do what I write. They're garbage right now. no offence. you tried your way now listen to us on here, we wanna help.
Good Growing.