Need Help

Hello everyone, this is my first post but i've been reading on these message boards for a while now. Anyway I was wondering if anyone had any advice on what was wrong with my plant. I'm running a dwc and using GH 3 part solution using about 50-40% of the recommended solution. There seems to be yellowing around the tips of some of the leaves. I've already had one problem with my plant but i managed to save it, but now i'm out of answers. So any help would be greatly appreciated. Sorry if the photos are a little blurry but i think you can get the gist of it. Thanks in advance.

anybody please help me

anyone?