my friend tank a 5.5g is about 6 to 7 mos old. it was reset because of algae. when it was brought to me it is an empty tank so i started working on it by putting back the subs consist of local black soil and laterite. since the two subs was mix after filling with water it became cloudy. but in two days time it became clear and i started to put some easy plants. when my friend brought back the tank to his office after one week he called asking what was that white liquid coming out of his diy co2 that make his tank water cloudy. it was solved by attaching bubble counter/diffuser. this time again he is complaining after water change using aged water the tank water became cloudy. can anyone tell what really causes cloudy water because i don't experience this things in my tanks. thanks.