Review: Matrix -- better than Purigen

Discussion in 'Fish Tank Filters' started by aylad, Mar 2, 2015.

  1. ayladWell Known MemberMember

    I've posted before that I don't like the concept of Purigen. I see it as being just another semi-reliable "miracle cure" like Ammo-Carb and whatever.

    If you're looking to reduce nitrate buildup in your tank, I wholeheartedly recommend using Seachem Matrix instead.

    How I know it's effective

    I've had Matrix running in the top basket of my SunSun HW-302 canister for almost a year now. I'd never really been sure whether it was doing anything other than serving as basic biomedia, until today, when I tested nitrate levels in the tank for the first time.

    There's a story there -- the last API kit I got had a defective nitrate test, and I never got around to buying a replacement for it (until recently), I just tried to keep up with my water changes. The last couple of weeks, though, a combination of illness and horrible weather has kept me from doing a decent water change on the 55 (I have to run a fill hose from an outside faucet). I was worried about the nitrate levels, so I pulled out the new test kit that had just arrived via Amazon.

    No nitrates. Zero, zip, zilch, nada.

    "Oh, great," I thought. "Another defective kit." So I tested it against water from a tank I'm using to cycle sponge filters. There's no substrate in the tank, no ammonia-removing agents, no plants, no way for nitrates to be reduced. I "feed" the tank every time I feed my fish, to keep a supply of ammonia in the water.

    The cycling tank immediately showed nitrates. The water from the 55 never did.

    There are live plants in the 55, but there aren't that many. Anacharis is the only plant in the tank that grows fast enough to have a noticeable impact on nitrate levels, but A. there's not that much anacharis in the tank, and B. I admittedly overfeed the tank to make sure my cories get food despite the 3 angelfish trying their best to snatch it all. Also, C. I've got about 2-3 dozen pea-sized mystery snails in a breeder net, and they get fed quite a bit. There's a lot of food coming into the tank, is what I'm saying. I really don't believe the plants could keep nitrates at 0 by themselves.*

    How it works

    Matrix doesn't bypass the bacterial cycle the way Purigen does. In a way, it COMPLETES the cycle. Standard biomedia provides shallow layers of surface area for aerobic nitrifying bacteria. These bacteria suck oxygen and nitrogenous waste out of the water and metabolize it first into nitrite and then into nitrate.

    Ever wonder why ceramic noodles have that hole through the middle? It's so that oxygenated water can permeate through the entire chunk of ceramic -- it allows aerobic bacteria to grow even inside internal cavities in the ceramic.

    There's another type of beneficial bacteria that can show up, though, and that's ANaerobic DEnitrifying bacteria. This bacteria can break down nitrates, which are toxic in large quantities, into... er... other, nontoxic substances. (Sorry... I'm not a scientist.) Don't quote me on this, but I believe the nitrogen specifically converts to nitrogen gas, which is inert (it's mostly what you're breathing right now).

    Matrix allows for the growth of aerobic nitrifying bacteria on its surface, but it is designed to support an anaerobic environment within the chunks. By the time water reaches the interior of the material, it has been depleted of oxygen. This creates an ideal home for denitrifying bacteria and mimics the effects of deep substrate beds in natural aquatic environments.

    How to use it

    For best results, place Matrix in the last tray of a canister. Use standard mechanical and biological filtration media first; as the water passes through the standard biomedia, it will become depleted of oxygen. By the time it gets to the Matrix, then, it will be that much more ready for anaerobic bacteria to do its thing.

    Because Matrix is a biomedia rather than chemical filtration, it doesn't need to be refreshed, rejuvenated, replaced, reset, or whatever other "re's" you have to do to Purigen and other chemical replacements for natural processes.

    Seachem says Matrix can be used in other types of filters as well, but that it will work less efficiently due to higher oxygen levels.

    * Seachem also says that Matrix is highly unlikely to reduce nitrate levels to zero. As I stated above, I do have some live plants in the tank. In my case, Matrix is lowering nitrates to the point that my plants can polish off the rest of them.

    Is this an excuse to skip water changes?

    No. No, it is not. Plants and fish live better when trace minerals, nutrients, etc. are replaced on a regular basis. There is no substitute for clean water. I do see it as a way to reduce the urgency of water changes, though -- when life happens and you can't keep up with your tank maintenance, this is a safety net. It's not a free pass to be lazy.


    Seachem website  ,  
  2. FranMValued MemberMember

    I used Matrix and it made not one bit of difference, however, the product claims to work best in canister filters. I have power filters. (I reduced the water flow as much as I could in the power filter as recommended). What I found that actually does work is NitraZorb. Myself, that is the product I would endorse.

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