Decreasing your electrolytes will have no effect on pumps or not, that is something that is more essential to the brains function and other neural secretions.
It sounds like you're experiencing AAS induced pumps by way of chronic exertional compartment syndrome (CECS) occurs during hyperemia which happens during heavy load and stress. What's happening here is the exit flow of fluid is the culprit, AAS can contribute by the increase of fluid and water retention, and the increase with rbc's, nitrogen, increase in the blood flow circulation, and also having a a heavy glycogen storage surplus.. the muscle obviously is filling with blood and fluid faster than it can exit the fluid therefore the fascia tissue around the muscle it's not able to expand and this is what is causing the painful pumps with compartment syndrome.
I would reduce the intake of any carbohydrates on the day of training along with any creatine. The addition of excessive sodium will also be a factor, just consume clear fluids..
Take longer breaks between sets along with stretching, I recommend bringing in one of those roller wheels or those massage guns and apply that accordingly to the areas that are affected..
There's absolutely nothing wrong with taking longer breaks to allow yourself an opportunity to recover..
this happens to me often and what I would do is capitalize on this opportunity to go work a smaller group for muscle rounds, maybe some cables for arms or something.. laying down and putting your feet up right also helps..
If your pumps become too debilitating you were not obligated to complete your entire leg session in one day and you can break it up into two different sessions, quads and calves, and then a few days later do your hams and Calves..
The added bonus is you can capitalize on this by allowing the pump to stretch the fascia tissue. When your return comes too painful just break it up into sessions.. also I'm a huge fan of getting my stretching done while doing my movements. Limit the intensity of your warmup.and try to get most of your stretching during your Lift..
Also try doing sumo squats, and don't be afraid to pass up on the squats for next couple sessions and just focus on the leg press machine along with your feet placement.. you have plenty of alternatives..
Take home notes.. cut back on the sodium, increase your fluid intake with clear water.. and break up your leg routine.. and try to get more of your stretching employed during your list rather than doing more warm up sets.. and don't frown on the leg press machine it may be your biggest tool for the next several weeks...