You should be doing water changes daily to get those nitrates down
Cheato is also a macro algae that removes nitrates from the water column as it grows.
Top off are the water you replace from evaporation, you should only be using distilled or RO/DI water (and when you make up your saltwater for water changes, never use tap)
Also stresszyme isnt going to help anything, its just putting more chemicals into the water that dont need to be there. It doesnt do anything anyways, just a freshwater idea that they tried to copy and doesnt work in salt.
Algegon is also not helping anything. Its killing the algae in your tank, which is decaying and releasing nitrates back into the water column. It is also damaging the symbiotic algae living in your corals - that is how they get food from light.
Also, most filters need to be more than rinsed. They need to be completely changed out every 3 or 4 days.
Other things you should get going to get those nitrates down - skimmer + fuge with cheato or algae scrubber.
What are you feeding and how often? How many fish do you have in what size tank?