Wow. Lots of questions. I think I can help with some.
1- I think most people are goign to tell you that your LR
is your filtration. YOu could probaby add soem type of canister filter if you wanted to but it it probably best to add a sump/fuge. IT woudl also be good to find a good skimmer for that size tank especially if oyu are goign to have fish in it.
2- I foget the calculation. Other can answer this better.
3- I foget the calculation. Other can answer this better.
4- # of powerheads depends on flow output and flow required. Different thins need different flows. SO more information is needed. But you are probably goign to beed somehting pretty big or a few smalelr ones. Typically people liek to do 2 PH at max inside a tank.
5- Again it all depends on your desires. What kind of coral do you wantto keep. I say a a general rule 3-5 watts per gallon is good for lower light stuff liek shrooms
. 5-8 watts per gallon is good for soem medimum stuff (bubble coral) and 9+ is good for higher requirment stuff. Clams are i na
leage of their own and you would probably need like 15 watts per gallon but I do nto keep clams so I don't know.
6- I suggest doing an open sump and keeping the top of the aquarium sealed to cut down on evaporation. As for lighitng I think it is probably best to keep it off the top to help cut back on the heat tranfer from you lights into the tank. YOu may have to buy a chiller for a tank that size. If you want to get away with not purchasign a chiller then I really suggest yo udo the sump and keep your lights away fro mthe top of the tank.
Hope that helps a little.