i still think the 5.5 was right,your runoff is 5.5 you feed 5.5 that means no salt build up,maybe this will help
PPM FOR HANNA CHART PPM
seedlings-early sprout 100-250 ppm ec 0.2-0.5
early veg 300-400 ppm 0.6-0.8 ec
full veg 450-700 ppm 0.9-1.4 ec
early bloom 750-950 ppm 1.5-1.9 ec
full mature bloom 1000-1600 ppm 2.0-3.2 ec
ok there are the ec and ppm readings,you are without a doubt in seedling stage,so follow that on chart when you feed,coco needs to be moist at all times,but it also needs drainage,put your coco medium in the pot and leave 1in from the top of pot,this is a good reference point for your watering,fill your water to top let it drain out,coco also doesnt like change leads to problems ,when feeding use nutrients each time you water,ive found that the ,feed,water,water knocks shit all out of whack,so even if your plants look like the dont need any put in a bare minium,got to be something each time ,except when its gettin close to harvest time and usally thats the last 2 weeks of its life,you also have to put
cal-mag plus in each time,coco isnt like soil and get it from the soil,you have to give it to the plants,as mentioned above get you a pot same size fill with medium that your using ,just like the pots your using,soak that bitch down,let it drain till nothing else comes out,ok this worked great for me when i first started,instead of lifting pots,lean the mock pot towards you slowly,you can fill the resistance and weight,once you feel that exchange of weight,you can take your seedlings and do the same thing ,lean them towards you,you will feel the diffrence,now the diffrence of a dry pot versus a wet pot will be easier for you to tell when you need to feed,i have also used those pots that you have that seedling in,they dont drain for shit,take that drip tray off and get a bigger drip pan to set it in ,not sure about yours but mine didnt have enough holes in bottom to drain well,so i took a drill and made somemore,with drainage the pots will dry quicker ,but remember we dont want coco dry,thats were the dryer pot versus the soaked pot comes in you want to be at least in the middle,your light is cool ,does it have a switch on it ,like 25% 50% and then 100%,if it does dial it down to 25% until we start getting some more leaves,you can work it up to full light once you start a 3 set of leaves,most important thing to all this and this is also true for indoor or outdoor growing of veggies and the herb we both love is enviroment,you control that,you mention humidity problem ,this young you want a lot of humidity,when you get to full veg running ABOUT 50% is adverage once them girls go to flower the least amount of humidity is what your looking for,for no make sure you have air circulation ,try to get the fan to swirl around the room in a vortec motion,dont point fan right at your plants ,just keep the air moving in the room,also important for not getting bugs,anyway im tired of typing and hope that i could help you out,i been there just like you and everyone else,dont just take my word ,get several opinions and decide which way will work for you best,good luck hope this helped