First, who told you you are not supposed to put CYA into the skimmer with a cartridge filter because you are! The CYA gets caught in the filter and slowly dissolves over the next week. It does not matter if the filter is a cart, sand, or DE.
Second, what make and model of SWCG do you have? That infor would be useful.
Third. Why hasn't the pool store tested the salt level of your pool? Do they know you have a salt pool?

YOu need to add chloirne to get your FC up to about 20 ppm to clear the pool and you need to keep it there. Start by adding either 10 gallons of 6A% bleach or 5 gallons of 12% liquid pool clorine to your pool and nothing else.

I suspect the Mustard Eliminator is either sodium bromide or an organic ammonia compound. It will do not good at all in a pool with low CYA such as yours and was a waste of money.
The clarifier was also a waste of money.
You really need to get your own test kit and test your own water since the key to clearing a green pool quickly is to get the FC level op and KEEP IT UP since the chlorine will be consumed very quickly as it fights the algae. You have increased teh chloirne demand by adding the mustard eliminator and it really will so nothiing for ou sinc eyou did not have an overstabilzied pool (which is where it is useful).