Approximately 4 months ago we set up three identical systems using different substrates in the refugia. As seen in the photos from those tanks in Jan. 15, 2012, algae has become so problematic in the tanks that use the Fiji and CaribSea substrates, that frequent removal of the algae was necessary in order to prevent it from overgrowing the corals. So in order to continue our experiment long term, more snails were added to each tank after the nuisance algae was brushed off and removed. In addition it became necessary to siphon detritus from the tanks, change ECO Phos and activated carbon. We also started adding low dose of kalkwasser solution instead of just regular RO/DI water for evaporation. These changes stabilized the systems and all of the corals are growing well. However the coloration of the corals is different depending on when different substrates are used, such that the blue color is good but not red in the CaribSea tank, while red is good but not blue in the Fiji tank. The best growth and colors of corals is in the EcoSystem tank, however they have to be seen in person for the differences to be fully realized.