I started sinus irrigation a couple of months ago when I had severe congestion. I found during that time I had to irrigate three and four times a day in order to get results which happened right away, but took a few days to completely clear up. I used a Neti pot and ran almost a cup of solution through each nostril. This continuous flush washes out germs, viruses, fungus, and anything else that may be there. The solution I used to two cups of water is: 1 teaspoon of sea salt, 1/2 teaspoon of soda. Use body temperature water. The soda breaks through the mucus and the salt keeps it from burning. I eventually adjusted this with tea tree oil - one drop at first, but have worked my way up to twelve drops. The amount of tea tree oil will vary depending on the brand you are using because some are more potent than others. What I found with the tea tree oil is that it had clearing effect that lasted beyond the irrigation. It is also an antibiotic.
I do this now once a day and my sinuses are clearer than they have been in decades.
This may be what you've already done, but I found that you really need to keep that saline solution running through your nose and a Neti pot keeps it going. I use the original Neti pot but if I get a replacement I'll get the stainless steel one which has a larger capacity and a better irrigation without spills, and it doesn't break.