White growth in gravel

Question
Every since moving to the current address I have had trouble with my 55 gallon tank and this white/grey mold attached to my gravel and it is hard to get off. I have not had this problem in the past 35 years. I was told there is a lot of phosphate in my water, could this be a part of the problem. Some of the fish in this tank are 13 years old. 1 silver dollar, 2 angels, 6 Cory and 1 beta. When my water is tested at the local pet store they say it is perfect. I can't stop the mold it even grows on the plastic plants. It is hard to get off and out of the gravel. We do not overfeed, every thing is consumed within a few minutes. Like I said I have never had this problem until I moved and have this water.Thanks for your help.

Answer
Hi Steve,
The reason why you have this problem is because it is a new tank setup.  It happens to many new setups, including my set ups.  You did not have the problem in the past because the past 35 years, the tank has had PLENTY amount of time to cycle.  But since you moved, you have restarted the tank. Cycling only takes a month or more.  By restarting a tank, you have removed all beneficial bacteria necessary to break down organics.  So now the tank is compensating by regrowing these bacterias agian.  The white growth are bacteria, and I believe they are heterotrophs which multiply much faster than autoptrophs.  The slimy/mold looking growth will go away by itself once the tank is cycled.  Even if the food was consumed, it grows because of organics in the tank, even plain tap water has a few organics.  Also, by conditioning the tap water to make it safe for fish, allows the water to be perfect for inhabiting bacteria.  

Agian, once the tank is cycled, it will go away on its own.
-Matt-