Cichlids by Sanderling

Turning Sump Design on It’s Head

// October 10th, 2009 // Filtration, Fish Room Projects

I’ve always been a cannister and HOB filtration kind of guy. I also like sponge filters but in spite of more than twenty active years in the hobby I’ve never had a sump. I guess I’d rather use any container big enough to be a sump to keep fish!

All good ideas have their moment however and it was simply a matter of time until I needed the bio-filtration power that only a sump with wet/dry flow capability can offer.

I recently put together a fry growing module for three species of Aulonocara in my fish room. The setup was simple enough; three 110 gallon stock tanks arranged in series filtered by a Fluval FX-5. Rated at 600 plus, gallons per hour, I figured the filter could handle the bio load no problem. As the population of juveniles and sub adult Peacocks approached 500 or so, I realized that with the amount of food I was using, I needed more filtration power than my original setup could provide.

I found a powerful submersible pump rated at 3000 gph. By running the tanks in parallel rather than in series, and collecting the discharge in a sump through separate drains, I could have ten turns per hour in each tank-plenty of filtration!

My fish room is located in the unfinished corner of the basement of our house, usually known as the furnace room. This is only the real estate that my wife has allowed me, unencumbered, to indulge in my hobby. It has become very crowded and finding room for a traditional sump design big enough for a 330 gallon system would be difficult. In fact I only had an area 2 ft square to work with,  squeezed in between my water heater and my new system.

I decided the only logical approach would be to build a stacked system; a bio-tower above a sump, with a return manifold fed from the 3000 gph submersible pump, located in the sump.

I settled upon a 50 gallon sewage basin as my sump. If your considering using one keep in mind they are pricey but there is lttle chance you’ll be tempted to use it as a fish tank and scrap your sump project. They also have the added advantage of having a 4” hub for a drain and a 3″ threaded opening that can bushed to any size you want. There is also a 2″ schedule 40 pipe clearance hole for the discharge line, a removable bolt down access cover, and a bung hole for heater and pump power cords. All in all it is a very neat package, ideal for the application. I got mine at Home Depot for $145 but you may be able to do better at a plumbing supply house.

For those who like to skip to the end to see how the project turned out, I’ve attached a picture of the (nearly) finished product. 

 

 

Here is a close up of the sewage basin showing the 4″ inlet hub that i bushed down to three inches with an MJ band. The return from all three tanks is collected and delivered to the sump via the 3′ drain line.

The 3/4″ valve is for an automatic water change system to be installed in the near future. the 1 1/2″ PVC braided hose is the return to the tank water supply manifold. The two 1″ hoses are for my FX-5filter, which I use to recirculate an additional 900 plus gph through the biotower. From the tank supply header, I divert aproximately 1200 gph through the biotower, which drains directly to the sump through the 1 1/2″ pipe shown above. This standpipe is not glued into the reducing bushing on the sump, making the biotower removable for cleaning as required.

 

The Biotower is smaller than the sump, at 30 gallons capacity. It utilizes a floor catch basin that is intended to be used as a sump pit for a house basement. Made from structural plastic foam, it is strong and light weight, measuring 22” tall and 18″ wide. 

Water enters the assembly from the supply manifold through a 3/4″ bulkhead installed in the lid of the biotower.

Water is sprayed over the filter media using FX-5 discharge difusers. The top two thirds of the Biotower is the ‘dry’ portion. Water percolates through the media to the bottom ‘wet’ third that contains submerged media. The submerged section also acts as a head pond (resevoir) for the FX-5 filter which runs in a parallel 600 gph circuit through the Biotower. This enables the 30 gallon biotower to process up to 3600 gallons per hour!

Below is a picture that shows the difuser arrangement. The FX-5 outflow is on the left.

The filter is divided into the wet and dry section by using drains. The high level drain returns water to the sump and the low level drain placed at the bottom of the basin, returns water to the FX-5. Below are images taken during a test to verify that there is enough volume in the wet section for the FX-5 to run without sucking the basin dry.

 The strainers are very effective at keeping the filtration media from plugging the drains. Their volume is sized so  that enough water can channel around the media to  ensure a high flow rate without  overflowing the basin. With maximum flow and no media, enough head is produced in the basin to reach the top face of the upper drain strainer-plenty of additional drainage capacity if requred.ion

al void you may find in a pile of pot scrubbies. I was easily able to fitme greasy chemical that you more than likely would prefer to keep out of your system. I ended up doing two loads..

It was now time to prepare and pack the media. No wet/dry filter is complete without a durable high surface area to volume ratio media for the bacteria to grow on.

I like to use  scrubbie pads for several reasons; they cost very little, trap small particles, allow air and water to flow together, and have huge surface area for bacteria growth. I also like to add in bioballs as well. They nicely fill into the ocaisional void you may have in a pile of pot scrubbies. I was easily able to fit 300 plastic pot scrubbies and as many bioballs into the biotower.

I recommend that you machine wash and quadruple rinse scrubbies before you use them with an ‘organic laundry soap’ prior to stuffing the biotower. They tend to be coated with some greasy chemical that you more than likely would prefer to keep out of your system. I ended up doing two loads…

After stuffing the wet (submerged) section with media another test verified that there is enough volume for the FX-5 to run without sucking the basin dry.

Final testing involved balancing the flow rate from the sump to the biotower. The higher the percentage of water going to the tanks, the lower the water level in the sump. It’s important to remember to fill your system completely with the pump turned off in order to ensure you won’t have a flood in the vent of a power failure.

Water returning to the sump falls in excess of 30″ which adds considerable aeration to an already turbulent sump. As the water drains the filter section it pulls air down through media from the top. This renews the oxygen supply for the bacteria with enough excess oxygen to saturate the return water in the sump before it goes back to the tanks.

 

 

The cam-lock fitting in the foreground is for separating the submersible pump from the plumbing system for maintenance. I like submersible pumps because they’re quieter and any heat they produce goes directly into the system, keeping the pump cool and warming the water in turn.

Within days of start up, the vertical sump proved that it obliterates ammonia and nitrite. The FX-5 was already cycled so the media in the bio-tower was quickly colonized. The design is fully expandible  with room for another bio-tower between the existing one, and the sump. With a little plumbing magic, a total of four bio-towers could be utilized, facilitating a filter that can easily handle a system up to 1500 gallons in capacity.