First, for anyone who may be new here, or may just beginning to follow these threads, I bought a new 70 liters aquarium on June 10th. It was intended for Tilapia fingerlings which were due to arrive the following day. A bit of a surprise there, upon receiving them. (More to that story by following the link.)
Then, we got a surprise on July 22nd, when over 100 (we didn't know how many at the time) Tilapia fry had hatched in the Radial Flow Filter of the aquaponics system.
Those little guys continued to grow by leaps and bounds. So, we built them a new place to live on August 31st. They moved in the following day. (On or about October 1st, most of the fingerlings will be transferred to IBC fish tank in the aquaponics system. The balance of the brood will remain in the drum tank.)
Now, the filter / sump, when I first built the drum tank, was a 19 liters (20 gallon) bucket. This was definitely too small for a 132 liter (35 gallon) drum tank. I knew I would have to build a larger filter / sump to hold the overflow from the new tank. I only used that for the time being, until I could sort out what I would do for a larger filter / sump.
Some time back, I had begun watching fish keeping videos and saw how they were filtering large tanks these days. (I had large aquariums as a boy, but have not been an aquarist for many years - decades.) It was time to update the database in the old noggin. I learned that, nowadays, it seems most people use sump / filter combinations, more than just canister, or other filters.
So, with what I had learned, off to the chalk board I went.
I just took the former home of the Tilapia, the 70 liters aquarium and had the local fish shop guy cut me several panels of glass to fit inside. I needed to create separate compartments for filtration. This is what I came up with - which works great by the way. Between the new sump (former aquarium), the over flow (the 1/2" PVC you see piped together), and the SLO (the 1" PVC piped through the wall of the drum tank) in the tank, the water is as clean as can be. Even solids don't hang around long anywhere in the drum tank.
Aeration enters the system in the sump. This also keeps the bacteria bed growing well, due to the first oxygen going directly to it. (The plastic scrubby filters between the matt filtering and the pump.) Photos to follow:
Off to the left you will see the pump (2,300 LPH, yeah, way overkill), plastic scrubby filters (providing bacterial filtration), matt and screen mechanical filtration with the large air stone on top, and off the right, the initial mechanical filter capturing the initial solids from the tank.
By putting the air stone in the sump, you remove a lot of surface disturbance in the fish tank. Now, the surface of the water is much smoother, so I can sit and watch the fish easier.
The overflow (off to the right), along with the SLO (Solids Lifting Overflow) piped through the wall of the tank, provide both surface skimming and solids removal from the bottom of the tank, respectively. I have never had a cleaner fish tank in my life.
The purpose of this aquarium is two fold. First, it is to filter the water from the barrel tank.Secondly, it is to provide a reserve to hold any water that drains from the tank during cycling AND during a power outage. (The water level will fill in the sump, but will not overflow it, in the event of a power cut.)
Afterthought: Ya know, if I were to add a bit of coiled copper tube and a fire along side, people would think I was runnin' a moonshine still.