sump construction questions

shamrock · Nov 21, 2021

good evening,

(sorry, thinking in metric, but will try to do feet/inches)

this will be for a freshwater setup (sorry, marine is probably too challenging at this stage, i need to gain some experience first)

i've been considering making my own sump using a used 3x2x2 glass tank (90x60x60cm). the display tank will be either 3x2x2 (85 gallon) or a 4x2x2 tank (115 gallon). i'll be using a eshopps eclipse medium overflow box with 25mm / 1" pvc.

mechanical filtration will be with matten filters of varying PPI (10, 25, 30 and 45). i might use filter socks +/- some form of foam in the first chamber to catch some of the detritus.

1) how thick do the glass baffles need to be?
2) to allow good flow, how much space should i leave underneath baffles?
3) how much space is ideal for the ? inflow chamber (ie drainage from the display tank)
4) how much space should i leave for the return chamber (pumped from sump to display tank)
5) should the biomedia chamber have fast or slow flow? does it matter? biomedia will be placed in media bags
6) i take it refugium should have slower flow (just my guess, i really don't know) - thefore baffles should be all the way down, rather than 1 up, 1 down (?)

please see diagram below - hope it makes a bit more sense there...

and as always, thank you for your time and input

sk

KrisReef · Nov 21, 2021

1. The thickness of the glass baffles could be any size since they won't be under pressure holding water like the main box. They do need to be thick enough so that they don't break if you bump them or put pressure on them when cleaning, I'd guess 3/16th of an inch would be the minimum I would use. (Sorry, I don't feel like converting to metric

)
Green questions, left to right:
For the intake box size, it needs to be long enough to hold your filter socks, or your sponge block, or a rollermat filter.

The space at the bottom? a few considerations: large enough to allow access for cleaning, an inch would allow adequatte flow.

Having the baffle making the flow go under and over forces water to travel though the filter media.

I don't think fresh water tanks use refugia as often as marine tanks, they just do water changes to remove excess nutrients.

The last box needs to be large enough to house the return pump, or have a hole drilled in the side to allow an external pump to return the water. For an external pump, fit the box to allow installation of a bulkhead fitting in one wall.

Also, for sump sizing, it needs to hold all the water that will drain from the tank during a power failure. The baffles should not go all the way to the top edge of the sump. They should be installed below the top to allow water to overflow inside the box if the filter media between two boxes gets plugged.

If you are going to go salt later, think about having an area for a skimmer as well as the refuge.

That's all for now.

Red_Beard · Nov 21, 2021

I ran a sump on a planted 90 for a few years. I just had a 20 long, but it worked great. Mine was set up with a bigger inlet chamber i filled with bio-balls and ceramic media. No bag, just let it all float (or sink). Then water went under a baffle with about 2 inch gap that had a coarse sponge in it for mechanical filtration sandwiched with another baffle to hold it in place. It was a big piece of sponge and it lasted 5 years just rinsing it out once a month or so. My sump didnt have anything else other than heaters in the remaining space with the return pump. IMO freshwater sumps can be super simple, no worries. Baffles 6 mil thickness is just right. I liked having enough space between baffles I could fit my hand or other instrument between them to clean once in a while.