Water changes will also remove unwanted nutrients. HOB filters don't do anything for nitrates unfortunately. They trap uneaten food and fish poop and add to the overall nitrate count. The only thing in the tank that will process nitrate is the small amount of live rock you have in there.
My tank (accidentally) got to 1.032 (nothing died) but I ended up taking about 4 inches of water off of my 29 gallon tank and just added fresh water with not salt slowly. It got down to 1.025.. A water change would be your best option..