im surprised your plants are doing as well as they are with a ph of 8!
must be hardy little guys!
time to buy some phospheric acid, its not expensive $10 for 250ml
have you got a pen ph tester strips or soil ph test kit?
i use a ph pen and have the other ph testing equipment,
the only downfall with the ph pens are, you cant cheak the ph of the soil directly,
this site has about the cheapist good ph testers ive seen,
http://www.eseasongear.com/hydroponics.html
as for the leaf damage its prob where you spiled alittle water with nutes on the leaf and the light burns the leaf,
how much space do you have to work with in your grow room,
and how much height do you have?