Nitrate removing filter media.

[drdrewr]

Seachem matrix/pond matrix does work to help lower nitrates.
All my tanks are low nitrate tanks filled with large fish.
All my tanks have a sumps as primary filtration.
All the sumps now have a min 10 gallons of matrix as it's only bio media.
The key I found to make this work, was to lower the flow rate from the pump to maximize contact time between the water and the media so as to allow denitrifying bacteria to colonize the low oxygen internal pore structure of the matrix media.

I found at 5x turnover I was getting very little if any nitrate reduction. It wasn't until around 2-3x turnover per hour that I noticed that one particular tank always had low nitrates compared the others. I slowed the flow down on the others, and within about 6-8 weeks the other tanks registered the same low nitrate conditions as the other tank. I know that slowing the flow down even more would be beneficial and you could probably get away with using less media, but I had to balance the mechanical filtration side out as well.

100% agree with the effect of Matrix. I didn't have to slow my filter flow, but, I use 40 liters worth of Matrix in all my filters. I switched to Matrix last April and it took about 5 months before I got the full benefits of nitrate reduction, but, I'm good ever since. I still do weekly water changes, but if I wanted to, I could probably do these monthly. I clean my filters, regularly, every 2 - 4 months. This is just as important and the media itself. In "my" case, if I don't clean the filters, the accumulation of bio-particulates defeats all of the nitrate-reduction controls that I employ (even the water changes)!!!