I just completed building a stand and 40g sump project. You can look at it here...I tried to give a lot of details:
https://www.reef2reef.com/threads/idocs-first-reef-tank-build-75g.317135/
I started out the exact same way...tried to design my 40g breeder sump like a Trigger systems sump. But, after looking into it further, I ended up going much simpler with the design. I think the fancy trigger sumps have all those crazy bells and whistles to attempt to justify >$350 for an acrylic box, lol. I used the following design for my sump, and so far, I'm very happy with it. This design allows for tons of space for future expansion...or can be altered to allow increased refugium space as well. So far, the refug space is plenty for me!
Some notes to consider:
1. The 40g breeder is the same width as the 75g tank. So, make sure you design your sump area of your stand to allow for this! In my design, I added about 5-6" on the back of my stand so my sump area wasn't so crowded. It also gives a nice little shelf behind the DT for storing stuff, lol.
2. Acrylic vs Glass baffles...I highly recommend glass baffles, 1/4" thickness minimum. When I bought my sump used, it had a single 1/4" acrylic baffles in it...bowed terribly! I believe the reason for this is the long width of the 40g breeder tank! Smaller width sumps probably don't have much problems with bowing, but that 40g breeder acrylic panel sure was bowed when I got it. Plus, glass bonds better to glass with silicone...acrylic not as good. I got the glass baffles cut with safety edges (a definite must) and rounded corners for the bottom pieces for $34 at a glass shop I found in town.
3. Fancy sections for drain pipe and sock holder area... Go simple here! Those fancy designs take up so much critical space in your sump! Plus, that first drain chamber is going to be a huge detritus trap that will be hard to clean out! Another downside...I initially had an almost identical design...the glass baffle special cuts were going to cost me over $200 alone! I now use a simple filter sock holder and let the drain go into my first chamber...easy cleaning access!
4. Bubble traps.... In my opinion, a huge waste of space! I have one final bubble trap and now I think that could have been done away with! I get no bubbles in the return section...and I get no bubbles in the refugium which is after the skimmer section! If you do use bubble traps...I recommend 2" between. Two reasons for this: first, easy to get your hand in there to clean the glass, and secondly so you could make a small egg-crate shelf to fit in between the baffles in order to place media if you later choose.
5. Use your skimmer to determine the water height for the skimmer section
6. Make sure you calculate the "open" space above your baffles in order to ensure you can handle the back siphon from the DT. It's easy to calculate and it is so often overlooked. A good piece of mind for when you shut off that pump...which will be often!!
7. Leave your return section big enough that you can have a good amount of water in there...this will keep your ATO from constantly turning on and running its pump! The space in my drawing is very good so far for me. I use a Tunze Osmolator ATO and freakin' love it!
8. Refug before or after the return section... Mainly preference here and what you plan to do with your refug. I have a 4x turnover rate going through my sump and so having it in the middle is ok for me. If you were trying to go with a 10x or greater turnover system, then putting it to the right of the sump would make more sense.
9. Use dark glass for your refug sump area! I used clear glass and the algae spillover from the refug light is growing green algae other places in my sump...but, it is sucking nutrients out of my DT, so I guess not too bad for now!
10. I saw somewhere you might be using Pukani rock? So did I...love it. But, plan on curing it for at least 6 weeks before putting into your DT! The stuff is so freakin dirty and full of organics deep in. The smell was putrid for the first few days...you don't want that crap in your DT while it is cycling!!! I cured mine in regular de-chlorinated tap water for 6 weeks and that seemed to work very well with minimal leaching so far (phosphates the biggest).
11. I agree with other posts (did you make 2 posts on this?...I seem to have read other posts with this same drawing that aren't on this post for some reason). No biopellot or GFO reactor until much later when it is needed. You don't want that stuff during the cycle anyway!
12. Don't run your lights during the cycle!
Hope this helps! Good luck!
