This is a photo of a HOB overflow with siphon break pump.
This is a photo of a HOB overflow without siphon break pump.
I tried both the CPR and Eshopps overflow boxes and could not keep them running quiet. If you're still in the planning stages and have the ability to drill the tank for a bulkhead it will save you a lot of headaches in the long run. With that I run a BeAnAnimal 3-pipe overflow with 1" PVC and have run 800 gph with my Africans and now down to 300 gph with my South Americans with a minor adjustment to the gate valve. I could probably run about 1200 gph max. The system is so flexible and SILENT!
Am I correct that a sump could cost less than even a budget canister?
Lets say a canister for a 75G tank costs $100.
Sump would be a 20g high tank (dpg sale). $20
Three or four pieces of glass (home depot, cut to size from larger piece..) $20 (?)
Diamond hole bit for drilling $15
Bulk Head $10
Hoses $ 5
DIY overflow box $5
Besides media, what am I missing?
For fresh water I think you might be greatly overthinking how to setup your sump. My 75g tank is running a 20g as a sump. ALL of my filtration is handled by 3 sheets of Porret Foam. The foam sheets are 2" thick and 12" x 12" square so they fit inside a 20g tank. They are 10 pore-per-inch coarse, 20 ppi medium, 30 ppi fine in that order. I take out 1 sheet every 6 mo and rinse it out, that is it for my maintenance. I still keep 2/3 of my biological filtration going.
The reason for baffles in a saltwater tank is to force out the micro-bubbles, but in a freshwater tank its not as much of an issue. I don't run any other media like carbon, purigen, etc. I've had this tank running like this for 3 years with healthy and stable African Cichlids, I just recently switched to South Americans.
One of the best ideas you can add to your tank if its possible is an automatic water change system. My sump has a bulkhead drilled in it with a 3/4" hose running into the wall and down to my basement slop sink. I have a 1/4" tap on the fresh water supply to the house (like you'd hook up a fridge/ice maker) with a valve set for a slow drip. My running volume is about 90g total (tank & sump) and the system changes out about 5 gallons per day. I vac the tank & sump once a month, about 5 gallons total...makes life so much easier!