You know what... I never had any direct experience with this particular tank. I have a JBJ Nano Cube 12g and love it! So I assumed that it should be pretty similar. However, after doing some further research in the tank (i.e. how the filtration works and the lighting), I can see some design flaws. For example, the light partially sits right above the exposed filter. That direct light in such close proximity can cause algae to grow on the sponge and spread out. Further more, the filter sounds like it sucks up water and sprays it on the sponge via a spray bar and the water just overflows and falls back in the tank. This sounds like a current problem which can result in a lack of proper circulation, consequently resulting in stagnation. Maybe this is a reason for seeing some mold? I would suggest trying to add a very low GPH power head in their to help with circulation. An airstone can also increase circulation (perhaps a combination of the two). And of course, the frequent PWC's and the reduced exposure to sunlight. I feel confident that these modifications will help. However, I'm only speculating because I don't have any direct experience with a JBJ 180.