Hello, I need some help with formatting a chart.

What I have already
https://imgur.com/uRanQPK

And what I need to accomplish
https://imgur.com/l5Qg9aQ

So as seen, I need to hide every other number and their tick marks, in this case 50, 150, 250 etc.. How can I do that? I have tried to go to axis options and change the Major Units from 50 to 100. That makes it look right, but then also the vertical grid line disappears.

So is there a way to make every other number and tick marks hidden from the version I have now? Or on the other hand if I put 100 as major units, is there a way to add those vertical grid lines between?

Thank you.