I believe I can drop NO3 to zero by just using car sponges. In the photo you can see I've made rows of sponges in a sump. A few days ago, I only had 2 rows of sponges. One in this sump and another row in my other sump. The NO3 going in was 40ppm and 10ppm on the other side of the sponges. The dark orange sponge row has been there for a year,
The water is flowing through at 20ml per second. The important thing is to make sure that there are no gaps in each sponge row as water will take the path of least resistance and flow through the gap instead of the sponges. Part of the sponge must have become anoxic as anaerobic bacteria is carrying out denitrification. Nitrite and ammonia is zero.
I added another row 3 days ago (the middle orange row) and another yellow one today (so 4 rows at the moment). I'll add another one to the other sump later, but that might be overkill. In the next few weeks, I should have zero nitrates. The main tank is bare bottom. This is a freshwater tank, but there is no reason why this would not work in a reef tank as well, so I thought I'd share.
The water has to go through a filter to remove solids before it goes through the sponges. If you look at the hose going in, I've attached the head of a cheap aquarium vacuum cleaner and filled it with 6 cotton wool buds. This is changed daily and takes seconds. That way, the sponges will never get clogged with detritus and they only have to process dissolved organics.
My sumps are slightly above my aquarium and gravity fed back, but the same can be done in a regular sump. Are the car sponges toxic? I'm in the UK and used Aldi car sponges (2 for £1) and had no problems. The cotton wool buds are unscented.
I'll let you know my NO3 readings in the next few weeks if anyone is interested. No coil de-nitrators, DSBs, fluidised reactors, carbon dosing or plants. Just plain, cheap car sponges. One good thing about this is if you need to move the tank, you don't have to disturb a DSB and release toxic, egg smelling, anoxic sludge. You can vacuum your sand without worrying about killing anaerobic areas. I'll probably change a row every month with fresh sponges so they don't get blocked with bacterial mulm.
The water is flowing through at 20ml per second. The important thing is to make sure that there are no gaps in each sponge row as water will take the path of least resistance and flow through the gap instead of the sponges. Part of the sponge must have become anoxic as anaerobic bacteria is carrying out denitrification. Nitrite and ammonia is zero.
I added another row 3 days ago (the middle orange row) and another yellow one today (so 4 rows at the moment). I'll add another one to the other sump later, but that might be overkill. In the next few weeks, I should have zero nitrates. The main tank is bare bottom. This is a freshwater tank, but there is no reason why this would not work in a reef tank as well, so I thought I'd share.
The water has to go through a filter to remove solids before it goes through the sponges. If you look at the hose going in, I've attached the head of a cheap aquarium vacuum cleaner and filled it with 6 cotton wool buds. This is changed daily and takes seconds. That way, the sponges will never get clogged with detritus and they only have to process dissolved organics.
My sumps are slightly above my aquarium and gravity fed back, but the same can be done in a regular sump. Are the car sponges toxic? I'm in the UK and used Aldi car sponges (2 for £1) and had no problems. The cotton wool buds are unscented.
I'll let you know my NO3 readings in the next few weeks if anyone is interested. No coil de-nitrators, DSBs, fluidised reactors, carbon dosing or plants. Just plain, cheap car sponges. One good thing about this is if you need to move the tank, you don't have to disturb a DSB and release toxic, egg smelling, anoxic sludge. You can vacuum your sand without worrying about killing anaerobic areas. I'll probably change a row every month with fresh sponges so they don't get blocked with bacterial mulm.
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