planning an upgrade.

[KErickson978]

i am planning on upgrading to a 40 gal breeder.
and have a few questions for it. i feel kindda lame really... i mean it seems like just another step bigger, but like in carpentry... measure twice cut once..
ok so my plan so far is to use a 40 gal tank with about 30 gallons in the sump/refuge area. i was also thinkin of adding a 2.5 gallon tank somewhere as a RDSB would this be to small to be effective?
I already have the tanks layin around here its just a matter of drillin and plumbing them.
one question i had on drilling the overflows was is it better to have external overflow boxes than internal? and if so would they still work on each back corner or would that stress the glass.

this tank is going to be primarily based around SPS corals and Tridacnid clams, with a few other things thrown in so i would prefer external overflows to save realistate for the clams when they get bigger thus delaying the inevitable move to a 120 for a few years

whats the best type of substrate grain size cause personally i prefer a sand bottom. but right now i have a medium grain size and occasionally algae starts growing on it, and its never very white. so would going with a finer grain and adding a cucumber keep the sand white?

would two 250 watt MH be adequate?
or could i do all T-5's with individual reflectors?
if i go with MH would i need a chiller?

for pumps i am open to suggestions. ive got a mag 9.5 pump currently for my return and am wondering if its going to be to weak for the 40 and if i need a better pump and should just mold this one into a closed loop.

the skimmer i have now is rated for 90 gallons i beleive so i will be needing a new one of those as well if anyone has any suggestions

would two 150watt heaters be enough? i dont want one heater just in case of a short or a meltdown. be safe than sorry..

Thanks to everyone in advance, and i shal be posting pics of the build/setup

[KErickson978]

bump