CompMage
Aquarium Advice Freak
I had that problem when I started up my most resent 55G tank. My suggestion is to just let it be. Do a small water change every day to try and keep everything under control while the tank cycles.
It took my tank 3 or 4 days for the white haze to go away. I had it tested and everything was fine. My tank too was second hand.
But to be safe, take about a 500mL of your water to your LFS and have them test if for everything they can. Some LFS offer a more deluxe test if you ask nice, some will do it for the same fee if you ask nice. Have them do that for you and get back to us with the results.
Main things
PH, KH(Amount of Carbonate in your water), GH(General Hardness), Ammonia, Nitrate, Nitrite, and if they can test for chlorine and chloramine.
It took my tank 3 or 4 days for the white haze to go away. I had it tested and everything was fine. My tank too was second hand.
But to be safe, take about a 500mL of your water to your LFS and have them test if for everything they can. Some LFS offer a more deluxe test if you ask nice, some will do it for the same fee if you ask nice. Have them do that for you and get back to us with the results.
Main things
PH, KH(Amount of Carbonate in your water), GH(General Hardness), Ammonia, Nitrate, Nitrite, and if they can test for chlorine and chloramine.