Quote Originally Posted by bigtopsfinn
...I had this problem before and I suspect it was due to over-fert, which locked out other nutrients. I did a small flush and backed off the nutes and didn't have that problem anymore...
I should add that i was using too much PK 9/10... I suspect that the yellowing like yours is from nitrogen deficiency. But I don't think you should give it a bunch of nitrogen, not good for flowering.