The tank looks nice. Appears to be good open space, but the bottom of the reefscape looks a little closed with too many small rocks. Open up some channels across the sand underneath the reefscape by moving some of those small rocks up.
The tank is being overfed. When I feed, especially just a couple fish, I drop in a few morsels and watch the fish eat them. I watch them gobble those pieces up in about 15 seconds before dropping in a few more pieces. Then I stop and maybe on occasion do it one more time, always making sure they eat every decent sized piece of food.
On feedings, I skip at least one day per week, but some days I make it "Sunday dinner" and feed them almost double the amount of other days.
The top of a tank should not be covered or if it is covered should have plenty of places for air exchange. Always remove glass covers. Fans which may cool the lights during the day can help but at night when gas exchange is just as important, the lack of air movement can be unhealthy. Simply placce a small block under the tank lid to open up space for air to move in and out. Lack of oxygen and too much CO2 in the water because of poor gas exchange is another cause for lowered pH (especially at night
) and Cyano growth.
In the pic, I cannot see the Macroalgae. From your description, it's probably Chaetomorpha (kate-o-morfa).
The Alk and Ca are good.
The pic appears cropped above the tank bottom so I can't tell for sure but I'm assuming it's 1-2"of sand in front and a little more in back.
Assuming the sand is the common Caribsea Special Grade Reef Sand, it would be helpful to add some Oolitic sand. This will enhance the biofiltration by provided a ton more surface for bacterial growth. Oolitic sand is the best for this. I'll give you some free Oolitic sand, if you want to call and come get it.
This is unwashed Oolitic Sand:
Below is CaribSea Special Grade Reef Sand. I reduced the size of the CaribSea pic so the actual size comparison between the two sands is pretty close. Because bacteria are so microscopically tiny and because they like to live on surfaces, many times more bacteria can live in the same amount of Oolitic Sand because the smaller size means a huge increase of surface area. Does this make sense?
Edited by Mark Peterson - October 28 2010 at 8:34am