Nitrate reduction from a cannister filter

I found this on another forum from several years ago. It had no responses, but it seems pretty logical to me. I was thinking about trying on one of my Eheim 2262. It would be filled with Poret foam. Does anyone have an opinion on it?

I may have just figured out a way of lowering nitrates in my tank. Having viewed some commercial biological nitrate filters it is clear that to remove nitrates you need anaerobic bacteria. With a normal external canister filter that circulates water from the main tank at a relatively high rate you have too much oxygen for the anaerobic bacteria to thrive.

In order to breed the anaerobic bacteria you need a flow rate low enough to guarantee that your canister filter contains oxygen depleted water. The commercial systems use a drippier to feed the filter with drops of water, where the flow rate is 1 - 4 l/hr ( 0,25 - 1 gph) for a small tank (5 L canister) and 12 - 30 Liter/hr ( 3 - 8 gph) for a large tank (30 L canister).

Building a drippier system is complex but putting a timed relay on a normal canister filter isn't. I set a relay timer circuit to 90 seconds off, 2 seconds on. I measured the flow for one pulse to be 100mL, which averages out at roughly 4 liters per hour. I used a spare AVEX 600 external canister filter with a volume of 2.3 Liters. I replaced some of the filter medium with porous clay pebbles to increase the surface are and encourage bacteria growth inside the pebbles where the oxygen will be at its lowest. I used a Velleman adjustable interval timer placed inside a plastic box with a 12V wall mounted power supply. http://www.vellemanprojects.com/be/e...iew/?id=366732

I took some water out of my tank with quite high nitrates and put it in a test tank. I then left in with my anaerobic filter for about 1 month. When i measured the Nitrates they had fallen to zero. I have since connected the filter to my main tank and I'm eagerly awaiting the results.

Has anyone tried this before? Will it work on my main tank? What removed the nitrates from my test tank?

Thanks

Read more: http://www.tropicalfishkeeping.com/diy-aquarium/home-made-nitrate-filter-5657/#ixzz3RvH1mX5e

The link to the controller id no good, but I think it would be pretty simple to find something else.

I didn't do this. I copied it from another forum.

mark, I guess my nitrates would be higher then the 40-80PPM with 4-10 50% water changes weekly I have now if Matrix truly controls nitrates.

I'm glad it works in your case, mark. Yes fairly high bioload. I already have 20 liter of Matrix along with my massive water changes and the Matrix makes no difference after more than a year.

So I decided to take the plunge and try this. I will be using an Eheim 2262 which holds about 20 liters of media. I am going to put mostly Poret foam in it with a layer of Matrix on the bottom and top. I don't know why I am adding the Matrix, but I am . I ordered an adjustable timer for Hydroponics to control the flow. http://www.vminnovations.com/Product_15631/TMP-DNE-C-A-P-Day-Night-Temperature-Controller-.html
I am thinking to start I will have it run about 4 seconds per minute. I need to test actual flow to be sure. I plan on carbon dosing with sugar water instead of the normal alcohol due to cost. I really have not come up with a good way to do it other than sticking my arm in and putting it into the intake with a turkey baster. If someone has an idea I would like to hear it. I will update and take pictures when the timer gets her in a few days.
Please leave me any ideas to improve it.