Basically i need to know how to get rid of pitting. I tried navel jelly which did get rid of the rust but not the pitting.

Will sand blasting work? Or are there other method(s)?

You don't want to do anything to remove the pitting. Since you can't add metal back, all sandblasting or any other method of lowering the metal to the depth of the pits would only further weaken the tubes.

If you're painting, the primer coat will fill the pits, though you might need 2 coats to do a better job.

Shotpeening - like sandblasting, but with steel balls - will help blend out the edges of and serious pitting without removing more metal. In fact shotpeening tends to strengthen the tube by easing some latent stress risers. I doubt it's worthwhile for your purposes unless the rusted area is deep and extensive.