I usually do a water change about every couple of weeks or so depending on how it looks .I get a red algae on the acrylic green algae on my live rocks and im finally getting coraline algae the pics are today 12/16/2014 i just did a 20 gallon water change and cleaned sump i cleaned the sump pretty good my question how clean should i make it but to not get rid of all the benefits of the diffrent algaes.I just started getting like a brownish algae on acrlic and keeps coming back.