Acroholic;389663 wrote: No need to plan for it now, unless you are certain you are going to do it. You really don't know at this point if you even need a chiller. What you might do is determine a position for a chiller if you ever need one....meaning figure out and reserve some real estate for the placement of one. So many times we just place stuff where it is convenient at that moment.
Also, plumbing changes are a lot easier if you use vinyl tubing (IMO) for your returns, etc. Don't know if you like hard plumbed tanks or not, but I don't. Basically, with a tubing plumbed system if you need to change something, all you do is cut some vinyl and replace with a new piece after you do your changes.
I would set up your system without a chiller first, unless you are absolutely sure you'll need one, but keep in mind where it would go if you do decide to add it later. That is the way mine went: I didn't use a chiller at first with just 250 watt halides, then I went to 3 x 400 watt halides and had to add a 1/4 horse chiller, then I added a second tank with another 400 watt halide, followed by a replacing my 1/4 HP chiller with a 1/2 HP chiller. More equipment, higher wattage lights=more heat.