Hi everyone, I'm new and need help / advice.. I have purchased a 200 gal tank, everything included except rock, sand, and fish for $600. I had a 75 gal tank some years ago. The tank has been set up for about 3 weeks now and is producig golden brownish alge. Everyone talks about water changes and and how much and how often. I set up my tank using a combination of used and new live sand. My ammoia level = .25, nitrate = 0, nitrite = 0, and ph = 8.4. I used TAP water to start the system and added chemical to remove ammonia, chloramines, chlorine, along with water conditioner. When should i do a water change and how can i do it cost effected.