Thoughts on a 55g rain barrel filter/sump

[drukus]

I am working on some new filtration for my 180g and I am planning on using a 55 gallon food grade barrel I have.

The plan is to use layers of mechanical to bio filtration vertically.

At this point, I have seen some designs that plumb the inflow to the bottom and some that inflow to the top and pump it back to the tank via my pump.

I am leaning towards the gravity assisted inflow to the mechanical filtration at the top and having it pumped to the tank from the bottom but I wanted to see if anyone had any thoughts on why the opposite might be better.

Thanks

[Mike L]

I'm a little confused. Going vertically in a square sump like tanks allow media to be positioned to prevent bypass. How would this easily happen in a round container bio not so much but mech for sure if you mean filter pads. Also sounds like a cleaning nightmare regardless. Maybe a backflush system for sure. Still think a 55 or 75 gallon tank would be better and easier to maintain.
Mike

[drukus]

Mike,

You are probably right that it might be better and/or easier, but unfortunately I don't have a big enough spare on hand right now.

As far as how the mechanical filtration, it would work essentially like a large canister filter with an overflow plumbed in the top and a valve for draining the detritus at the bottom.

Perhaps I am just out to lunch though.

[tanksalot360]

I see this as an accessibility problem. If you'd like mechanical filtration to go course -> fine -> biological, then the top-side input would allow you to layer your media most accessible - with the course foam/etc accessible at the top and biological at the bottom. Bottom input (or top input with pvc leading to the barrel bottom) means the initial contact media (usually course foam) would be at the bottom and the bottom layers when clogged would not be as accessible.
My vote is to think of it as a large trickle filter stack with pump and plumbing contained. Be sure to have an emergency overflow on the barrel itself.
Would be interested in a drawing?

[drukus]

Here is what I was thinking.

The biological layer might be a moving bed with K1 media (using air pumps), static porous media or both.

To Mike's question, how do we force flow through the media and not around the media? As in a horizontal sump, the media will fit tightly against all sides and the separators between levels will be perforated to distribute the flow.