Yes, i think that the leaves are necessary until they are completely dead. I wish i could remove them. About GH nutes, you must use a PH balanced water, but it's OK. I use now a lot of flora bloom, like 300 cc a week, yes, that's correct, in 72 liters of water every week for 12 plants. They drink all the water. I feed them twice a week. I added air pomps, i have 3x540 liters/hour of air and that's better. And i add a little of CO2 with baking soda and vinegar.
Thanks for comments.
Fhydro