Thanks for the suggestion, I will be reading the topic when I have a little free time, with the wife and a 3 year old son it's a bit complicated . I do weekly water changes and siphon the substrate, angels are not a very clean fish, I have kept the water that comes from the water changes in a 25 gallon container and added a little new water with liquid bacteria from brightwell aquatics. In addition I have placed a pair of scalars that come main tank so that the fish continue to "dirtying" the water. Last weekend my 10 gallon tank where my Croaking gourami lived had a leak. So now I only have the wild scalare angel, albino pearlscale and the gourami croaking in the 35 gallon tank. 25 gallon container contains a koi angel and smokey angel.