algae lumps

Question
I have a 75 liter aquarium. We gravel vacuum, and change the water every month. But there is lumps of dark green algae growing onto the gravel, and it makes it harder to clean, as it spreads. It doesn't seem to be affecting any of the fish. We do have 2 Chinese algae eaters, and other small tropical fish including Mollies. Sometimes when they try to eat it, it sticks to their mouth. Is there a problem with the water or something??

Answer
Hi Holly:  How much light does the tank get???? Algae issues are almost always caused by too much light. Sometimes it can be caused by too much phosphate.  If you have the opportunity you can take a water sample to most any aquarium store and they can test the water chemistry for you.  There is usually no charge for testing water.  If you can do that and report back to me the chemistry values that would be helpful.  Sometimes with Green Clumping algae you have to scrape it out with a net and discard part of the gravel.  For now... lets see if we can correct the issue before you have to go to those steps... dave