Brand new guy here

Your doing very well so far!!! As long as the skimmer works, its good, now if you ask if its been outdated, mostproblably yes, most defenitely will be a better skimmer than an 8 year old one, either way, show a pic, i can be wrong. I would personally choose from your two options to go with 2-250 watt if i was gonna do MH. More light being distrubuted. But 2-400 would be ideal!! Refugium idea is great!! You dont need such a big fuge, you can problably make a good fuge out of 10 to 15gallons out of that 40, and still have space to run a skimmer, and a return area. LED's are personal details that really wont affect your tank that much, but do help simulate the moon effect, and calms fish down, and makes it look good at night. I have 5 LED's in my 125, and im happy with it, if you think you need 8-12, go for it!
Im not to familiar with what a plenum system is, so ima go ahead and research that now. All of this is simply my opinion, there not set guidelines!!

 

Some old skimmers can still work really well - especially those big ones. There are a couple I wish I still had. It's hard to say though... if it saturates the water column with fine air bubbles and is counter-current at least, I'd think it should work well going off your dimensions.

IMO plenums can work from what I know - I still have one in a freshwater tank - but they do take away from the depth of the tank and can cause issues IF SETUP WRONG - which many seemed to do at one time.

Bob Goemans - a plenum guy / aquarium enthusiast that writes for FAMA - moved his plenum into a separate sump which makes sense maintenance wise - easy to clean and won't pack from having rocks on it - and display wise.

Anyway, I lean toward not needed, but having some merit if you have the room. But plenums used to be a 4 letter word. The hysteria has died down though..

ANYWAY THANKS FOR JOINING 3REEF!

 

Definitely get a good skimmer, it's a must. If I could do it over I would do a deep sand bed, and lots of liverock.

Test kits are a must, you will really want to keep on top of calcium, alkalinity, ph, nitrates, and phosphates. In the beginning Ammonia, nitrite, and nitrates.

You should also get: hydrometer/refractometer, grounding probe, poowerheads etc.

Oh yes, WELCOME and good luck.

 

Dont get scared, but there will be a long list of stuff you need.

Test kits, i recomend to go salifert for everything you can. If on a budget, salifert calcium, and everything else seachem. That has worked for me well!

Hydrometer, or Refractometer are tools used to measure the specific gravity(salinity) of the water. This is Needed!!