Do you have a test kit? If so, what are your test results?
You don't need to "go back and do the nitrate thing", but you do need to know whats happening to the nitrogen cycle in your tank. Pick up a good liquid test kit for ammonia, nitrite, and nitrate.
What water are you using for water changes? For a saltwater reef tank you want to use RO
water to mix up the saltwater for your water changes.
That red stuff is most likely cyanobacteria. How long do you keep your lights on? Are you using tap water?
Reducing lighting hours to 8-10 hours a day can help fight cyanobacteria. Also if you're using tap water, the impurities feed the bacteria. Using good Reverse Osmosis/DIstilled water will help reduce the food for the bacteria.