No Live rock, just Seachem Matrix

[Swingline77]

I'm putting together a 90 gal abalone, chaeto, and (maybe) LR tank. Aesthetics are not important. From reading threads on other forums, it seems perfectly reasonable to replace LR with Matrix. I'm asking about it here for a second opinion. I've heard the recommended quantity of rock mass to water volume to be 1 lb/gallon. The Seachem website recommends 500 mL of Matrix per 100 gallons. If I were to be able to use the Matrix instead of rock, it would be such a major relief. I won't have to soak reef rock for weeks to months to remove phosphates, and I won't have to deal with heavy quantities of material. I would seed the Matrix with a piece of live rock, though.

I have several ideas related to this. I have two Fluval U4 in-tank canister filters (http://www.fluvalaquatics.com/us/product/A480-u4-underwater-filter/#.W4rAeuhKhdg). I was thinking of using one intermitantly when cleaning the tank. I'd put a filter in it, and run it as I'm blowing off the interior of the tank with a powerhead. This way, I can get detritis waterborne, then collect it in the filter.

So, I have a use for one of the filters already. As for the other one, I can use this for at least some, if not all of the Matrix, depending how much Matrix I use. I'm sort of reluctant to keep this filter in the aquarium at all times though, since I'm worried about it getting destroyed by calcium deposits in short order.

I can also make a device to house the Matrix either as an adjunct or a replacement for the U4. I can get a length of PVC, cap it at one end, attach an 80 GPH pump that I have, fill the PVC with rock, then have a screen on the other end to allow water to flow out. One disadvantage to this approach is that if I lose power to the pump, I can see the interior of the PVC going anoxic pretty quickly if power is lost. In such a power loss scenario, how long would I have before things go there's a real problem? One solution is to put more holes in the PVC, though this would disperse water flow.

Would all of this work? Can anyone comment? Thanks.

 

[mcarroll]

From reading threads on other forums, it seems perfectly reasonable to replace LR with Matrix.

Can you summarize what you read?

Live rock became "a thing" for lots of really good reasons. And the concerns you mentioned are peculiar ONLY to dead rock....real live rock would never be handled like that.

Also what is the overall goal, BTW? Why not just bite the bullet on around 1 pound per gallon of real live rock? Even less than a pound will work if you have some reason for not wanting so much.

Live rock is acquired for everything that's growing on/in the rock. Not nearly so much for the rock itself...

 

[Swingline77]

Sources:
Forum: https://www.nano-reef.com/forums/topic/359766-can-i-cycle-a-tank-with-just-matrix/
Manufacturer site: https://seachem.com/matrix.php
Forum: http://reefcentral.com/forums/showthread.php?t=2526998
Forum: http://www.reefcentral.com/forums/showthread.php?t=2587717

The salient points are as follows:
-Some of the posts deal with Soporax, and some with Matrix. Most info applicable to one is applicable to the other.
-Matrix is a synthetic rock that has a a greater porosity than real rock, allowing for a reduced volume to be used to support an equal amount of bacteria relative to real rock.
-Though manufacturers recommend 500 g/gallon, users often use at least 1 kg/gallon.
-Matrix will not disintegrate over time.
-Matrix should be used in a vertical canister due to detritus accumulation issues.
-Matrix should be cleaned periodically as a result of detritus accumulation.

The overall goal is to have satisfactory, inexpensive, small quantity medium for bacteria to live in/on in order to remove nitrogen compounds from the water. As for not "biting the bullet" on real rock, if it's the case that the benefits of real rock can't be had with Matrix, or something similar, then I'll certainly use real rock. The primary issue is one of not having to deal with a large mass/volume of rock. I'd rather deal with 2.5 lbs of Matrix than 100 lbs of rock.

 

[mcarroll]

Hm....I'm not positive I understand why dealing with 50-90 pounds of rock is a big deal. (The tank weighed a lot more, for example.)

The "function" of live rock is almost separate from the media it's on....so I don't consider live rock replaceable.

But without knowing more why you want to go in the direction you laid out I'm not sure that's a great answer for you. Handling "a lot" of rock is "normal" for a tank this size....but normal is only a rule of thumb.

Let's keep digging.

On thing is that it seems to take actual live rock quite some time to fully "seed" dead rock.

Even culturing dead rock in the ocean they "let it bake" for a year or more in most cases before considering it seeded)....so I don't think that's a great direction to go in.

From tampabaysaltwater.com's website (for one example):
"Rock from an upland site is deposited on our [ocean site], allowed to grow for a number of years, and is then harvested for use in your reef tank."

Years according to their standard....and they have lots of happy customers.

So...

Is there a specific advantage you're after to running it in a reactor-type vessel, like keeping the tank space more open?

Is this a display tank, or a support tank serving a larger/display system?

What do you plan on keeping as the main bio-load on the system? Just abalone and algae?

 

[ikolbaba06]

I use both dry rock and matrix. The dry rock has since turned into live rock and if you want to use less live rock then matrix is your best bet. It’s cheap and easy to clean and stays put without breaking apart. I went a little crazy with my 120 and added 8L and have since cut it back down close to 4L. It was just sucking all the nitrates out of the tank too fast. I have it sitting in a modified bin in the sump that the overflow water pours into.

I would also recommend if you start with dry you cure the rock before hand and also think about purchasing a few pieces of live rock.

 

[Swingline77]

Good to know that it really does work. Since I posted, I read of someone else just hanging it in a bag. This seems like a simple way to do things. I'll certainly put some live rock in the tank to seed it.