LVN Scope of Practice--Dialysis Certification, The Schools and New Grads Salary

Happy Summer Time!

Since there are few "segregations" in Nursing scope of practices, I just wander if an LVN is allowed to go to certain additional certifications such as a dialysis cert..

I hope it is allowed.

If so, then, there might be a different salary between RN dialysis certified VS LVN dialysis certified; even though the job descriptions are all about the same....am I right?

Anyone has information about training centers/schools of Dialysis Certification especially in Southern California? How long does it take for the training? How much...or paid training, maybe?

Any info would be greatly appreciated. Thanks!