20L sump compartment sizing

[jimbinsc]

I am starting on my DIY sump and have questions about the compartment sizes.
I plan on using an Eheim Compact + with a footprint of about 5x4 inches. I was thinking about making the return compartment 7 inches so the pump will be in a 7x12 space.
I want to make the overflow compartment 8x12 inches to accommodate a protein skimmer, if I buy one for the sump in the future (I have an HOB now),
So that leaves about 11 inches for the middle refugium section after including an inch spacing between the baffles.
Is that enough for the middle? Or should I make the return section smaller?

 

[jtomasi]

I have a 20l and will post pictures later, but keep in mind that the smaller you make the return area the faster water evap lowers the level. This can be an issue with bubbles going back into the display. another random thought; many people say don’t use HD glass for the baffles as it is too thin, which I agree with, but I couldn’t find thick enough glass and siliconed two $3 pieces together. Its working well so far, even after hitting it with pumps and things multiple times.

The answer to your "big enough" question depends on the size of your system.

 

[jimbinsc]

Thanks for the info. I didn't know that a smaller return side would mean quicker water loss from evaporation. Good to know. The system will be 75gal and a 20L sump.
I guess the question is not "Is it big enough?" but "Does it sound reasonable?" and would doing the size wrong have any serious negative impact?

 

[jtomasi]

Sorry I wasnt really clear - Not quicker water loss, that depends on heat/air contact. What I mean was the level in that specific compartment will lower/reduce quicker - actual evap will be roughly the same whatever the size of each compartment. (The underlying assumption in that statement is you are using a "traditional" sump design. You could probably set it up in a way that the return area isnt the "water evap" area but im not sure how that would work.)

Anyone can chime in, but I think it depends on what you are planning for that 11 inch area. I cant think of any serious negative effects, however, people will argue that too small of a refuge (DSB or macro) doesn't really do anything to help on larger systems (mrsaltwatertank.com, I believe). Im not really sure what I believe, I guess it cant hurt?

 

[Singlefin]

I dont know if i would make the return smaller. You may want a bigger return pump in the future or in an emergency. Also you need space for an ato and maybe reactors. Ill measure my 20l sump when i get home. It also depends on what you want in your fuge. I was planning on doing sand but scrapped the idea and only run chaeto. Last week i added a 5th baffle so the water now pulls from the bottom of the fuge instead of the top. The bottom looked like it was collecting detritus. Skimmer side should be as big as any skimmer you may want in the future. My tank/sump has been running for 6-7 months. Just added this baffle a few days ago. Good luck.