Does the tank you are getting have 2 overflow boxes?
A reef ready tank not only has the holes pre-drilled but also has 1 or 2 corner overflow boxes or 1 center overflow box. Look at THIS ILLUSTRATION
If you decide to go with a DSB
, go with 4+ inches of Caribbean (aragonite) sand. Home Depot sells it as play sand on the east coast for about $5.00 US per 50 pound bag. There are two stores listed for Ottawa, so you may want to check with them. You would find in the garden section and it's known as Southdown, Old Castle, or Yardright. I have 300# in my 125 tank.
Heater: You might also want to consider the Won Brothers Pro Heat II heater. No glass that could break. Big Al's does not seem to carry it, but many other on-line retailers do. Let us know if you need recommendations.
Water Movement: Most people here like the Maxi-Jets. I have 3 of the 1200's on a wavemaker and 2 Hagen 802's.
Sumps: You can buy pre-made sumps or make one yourself from a 20 gallon tank. Check the DIY
area or do a search for some ideas.
Protein Skimmer: I don't think the Backpack or Remora are sized for a 120. You may want to look at the Turboflotor Skimmer, ETSS, Berlin, or EuroReef.
My tank was originally filled from the tap. I now use RO
water only for water changes and top off. You should consider getting one now.
This is an expensive hobby as far as the initial setup goes. If you do it right the first time you'll save money in the long run.
I'm still longing for MH
lights. For now I'm using the Coralife Aqualight (2-36").
The best thing you can do is keep asking questions before spending your hard earned money. Read the Articles
and then ask more questions.