SP 300V problem

I've been printing fine for a few eeks, well I say fine but since I set the machine there has always been a slight horizontal line in the solid colors, unless I print on higher quality. I just wrote this off as a ink saving issue. Now I can't get any magenta to print. I viewed lots of post and they talk about pulling ink to the heads with a syrnge. Where do tou actually attach it to put the solution through. Oh yes, and I did a powerful clean, it told me to empty the bottle, did that but after the clean no ink was back in the bottle.