OK, so I have a couple pulse ultra power series batteries, 6s 5000mah, 45c. What would be a safe charge rate to charge at to get them done quickly and still not do damage to the battery, I charged one before at 10amp rate and it puffed the battery and one cell is now beat. I have a i charger 106B with a 250w power source.

Charge as fast as you are comfy with.

I charge way faster than the 3 to 5C rating. Balance charge each charge, storage to 3.75-3.8V. All 12 of my 6S pack, including the 1 lone 12S stick pack for my Logo 690 all have IRs around or below 1 mohm.

I suspect the cell that went kaput on you may have just been bad, period. I had a cell do that to my brand new OptiPower 30C 6S 5000. Noticed thay cell voltages werent quite right on my 406 and confirmed on my 308 that i had a bad cell.

I have been using LiPo since before they became popular for RC use. I know what the risks are, so LiPo police need to go preach their rules to another person.

Hard telling what killed that cell in your pack, without being there to see what the voltages are/were prior.

10A is 2C on your battery, it should not get puffed. I charge up to 5C without issues. I only balance charge though.
Ronaldo