amanda nice tank.
just an observation. the red rock just to the right of center appears to me to be volcanic rock. if it is I would reccomend removing it from your aquarium as volcanic rock contains a plethora of minerals and organic compounds that you dont want leaching into your tank. It may lead to unexplained problems down the road, removing it now would eliminate one more factor for potential problems.
Here: this is one sample of lava rock actual content may vary somewhat from rock to rock
Mineral Content
Nitrate Nitrogen.................................4.0 p.p.m.
Phosphorus........................................6.0 p.p.m.
Potassium.........................................59.0 p.p.m.
Zinc.........................................................6 p.p.m.
Iron..................................................10.0+ p.p.m.
Copper...............................................5.5+ p.p.m.
Magnesium.......................................2.0+ p.p.m.
Boron.................................................10.0 p.p.m.
Sulfate.................................................7.0 p.p.m.
Organic Material...........................................5%
PH.........................................................8.2 Units
Calcium..................................1.3 Meq/100 gm*
Manganese...........................0.6 Meq/100 gm*
Sodium...................................0.1 Meq/100 gm*
Cation Exchange Capacity..3.2 Meq/100 gm*
* Milli-Equivalent per 100 grams