good morning, i was just reading a thread on sand bed cleaning and it was mentioned that if you have enough flow across the sand that i should not have dirty sand, does this also include the brown diatom lightly laying in some areas of my tank. would you use a powerhead with a spraybar at each end. ( i am sorry my tank is a 150 gallon, 60 inch in length and is 24 in tall) if this is correct how low into the tank should the spraybar be . right now i have a mag 24 returning from my sump and 2 rio 2100 powerheads inside the main tank. however when i direct them where i think i get good flow across the sand bottom, the sand is moved and makes new hills that also hinders other sand areas. then i redirect them more across the middle of the tank, i get less sand disturbed hills but now i get some bottom diatom. i am using the coralife 24 ro unit for water changes and currently have new vho flourescents. any help or thoughts will be appreciated. thanks