Well done to you, you have been doing an excellent job so far, as to the CO2 system, i am not sure what she means by 'redo it' because on a pressurized kit, these are the procedures that need to be done:
*check drop checker, it should be green in colour, although you shouldnt have to worry too much about this because it is constantly set at the same level.
*check the gauges - PSI should be around 50-60, Bar should be around 1.5-2
*change the cannister, this only needs doing once the PSI drops very low, and TBH i would leave it for Sakara to do, pressurized systems can be dangerous if you do not know what you are doing.
*See if the diffuser/ reactor is clean of algae and debris. She may use a
glass diffuser in which case if there is a large amount of algae build up on the disc, then pour on some bleach and leave for 5 mins, rinse thoroughly, then add some dechlorinator onto the disk for another 5 mins, rinse off and place back in the tank - a fine smoke will be produced for a few hours so dont be worried.
I dont think there is anything else that needs to be done, as you can see from the list, there isnt really anything that needs 're-doing'
Hope that helps, good luck and best wishes to Sakara