Thanks everyone! I came into work this morning & the big ray had the big tank super cloudy. I think he was burying himself & playing in the sand A LOT! I did a 50% water change @6:30 AM & I just did another at 2:30. Should I continue to do the water changes trying to keep the tank as clean as possible? I had put 200 lbs. of pool filter sand in the day before, but I washed it very well before putting into the tank, but he is really stirring it up. I guess I'm happy cause the ray seems very active, but is there anything I should be worried about or doing with this situation other than water changes? On a side note, I think it's so cool how he comes up to me & really checks me out!