Thank you for replying to me. Did you know why I asked those questions? Because I read the thread of Danmuges and it hit me. I own a 100g reef tank for 10 years. I am having big problems with high No3 and Po4 problems. I did everything, I mean everything to export the high levels of phosphates and nitrates. Then a friend told me that I have an Old Tank Syndrome. I showed him pictures of my sump and he asked me how old was the crushed live rock used as a bio- media in my sump, and I answered him I never changed it in 10 years. He told me to take it off because the crushed live rock was the problem, it was leeching the high nitrates and phosphates, and replace it with new Bio- media bricks. I believed him and that day I take out all crushed corals, cleaned the sump and replaced with five Bio-Home bricks. I dosed Microbacter 7 a full 250ml bottle. By the time my tank filled up with brown algae that I don't have control on it. I clean it every day but still growing on the live rock it is growing on everywhere. I clean it today the next day it will grow again, it grows so fast. My tank is bared. For the live rock in my main tank, I was suggested to cook the 10 years old live rock in a food-grade plastic tank using new saltwater the same water parameters, powerhead and a heater close the tank and to do a full water change weekly so I don't kill the heterotrophic bacteria and don't cycle the tank again. I have been doing this procedure for the 5th week now. I was told that it takes to cure about 6 to 8 weeks. The live rock in the plastic tank is doing well my nitrates and phosphates have been reduced by half. But the main tank remained with high nitrates and phosphates. My fish and coral left in my main tank although high nitrates and phosphates are doing well. I think i lost all my beneficial bacteria in my main tank. Any suggestion please as I am brainwashed now?