Nitrate <> Nitrite. What you have in your tank is a biological system of bacteria or at least eventually you will have. Come of these bacteria help you to get rid of all the ammonia that is produced from fish poo, food left overs and other sources of decomposition in the tank. This ammonia is then used by the bacteria for energy and as a byproduct, Nitrite is produced and released into the water. This nitrite this then eventually gets used by other bacteria that use it to gain energy themselves. They further oxidise it to nitrate which, again, gets released into the water. Now, if you have a lot of anaerobic areas in your tank (areas where there is only very little dissolved oxygen in teh water), you will establish bacteria that use up that nitrate and form nitrogen to gain energy. That nitrogen then is lost through gas exchange. This is very roughly what happens during the nitrogen cycle in your tank. This is what you need to know to understand what you are testing when you test for ammonia, nitrite and nitrate. In a fully functioning tank, you normally don't measure any ammonia nor any nitrite as there are enough beacteria that immediately oxidise those compounds. Nitrate is a different thing as these bacteria don't have as many places to establish in our tank and the areas they are, the exchange rate is relatively slow.
Before you start investing in technology to get ridd of nitrate, let the tank first cycle and see if you need nitrate export to begin with (maybe you have only very little fish and therefore most nitrate will be used by corals and bacteria). The other question is also, if you only need to export nitrate or if you also have elevated levels of phosphate. There are different possibilities to export both at the same time.
Some possibilities are algae scrubbers, algae refugium, skimmers, vodka/carbon dosing etc.
All this information is only top-line and should just help you to start researching in the right direction. I'm still in the beginning of my own setup but if I can help you as a sparing partner for ideas, feel free to drop a line and I am happy to share my thoughts.