one thing I have learned over the last couple of projects is that it always costs less to buy something used and almost always costs less to buy something commercial (versus building it yourself, material cost wise). The main advantage to building one yourself is that you can have it exactly fit your needs, whether it be completely utilizing available space, or being set up just how you need it to be to match your drains and return lines, or pumps and skimmer, etc.
How tall would you want the sump to be ? 25" long is rather short (I may actually have a spare one up in the attic that we could work out a trade for).
Here is where I almost always start : This is the web page I use for "designing" any tanks that I build. It helps to size the acrylic for thickness and dimensions so all I need to do is take the cut list to the local Tap Plastics for them to cut (which they do on the spot, unless it is an odd shape, which none of these would be)
http://www.garf.org/tank/BuildTank.asp
You can figure for tap plastics that 1 sq ft would cost approximately :
per sq ft.
1/4" $6.00
3/8" $10.15
1/2" $13.60
3/4" $22.50
The sq footage is calculated as the overall sum of the different pieces, not how much of your cut list they can cut out of one of their sheets, which works out in our favor.
I chose a 16" X 16" X 25" tank as the "frame" for your sump (wider, taller or shorter all change the price, up or down). Oft times changing the dimensions changes the thickness of acrylic that their calculator says is required. So making it a little shorter could allow for using 1/4" rather than 3/8", knocking $40 off the price). That comes out to approximatley 12 SQ ft. At $10 per sq ft for 3/8" you are looking at $120 for the sump itself, figuring another $15 per baffle, for a basic bubble trap it adds $45 (3 baffles) ouch !!.
Sp you can see why it is often cheaper to find it commercially (where they buy raw materials in bulk and mass produce the units) or buy something used and use it as is, or do minor (or major) modifications to make it fit your purposes and needs.
Send me the exact dimensions that you are looking for and I will go up into the attic and check what I have up there. I know I have at least 2 sumps up there (both commerical, one a TruVu "Deluxe") and one of them may be what you are looking for.
