Substrate Depth in Planted Refugium/Mangrove Tank

[d2mini]

I'm planning on adding a 20x20 cube to my system to house 1-3 mangroves and a couple Benggai Cardinals. What i'm trying to figure out is what to use for the substrate and how deep to go. This will in turn help me determine the height of the tank.

So considering I need to plant the mangroves, what should I use for the substrate? I could use mud (Walt Smith's Fiji Mud), sand, a combo...
And how deep?
There will be a strong light hanging over this for the mangroves.

I'm concerned with things getting toxic down the road and these deep sand bed threads confuse me. I need some solid advice on the best way to set this up in a way that doesn't set me up for problems down the road. I'm starting from scratch on this so now is the time to do it right. Money no object. I'm just stuck to the 20x20 dimensions.

All help appreciated!

 

[billsreef]

I'd go with about 6 inches or so of mud or fine sand for the roots. Either will work. Not sure one is really better than the other, having grown them in both with equal results. As for the confusion of the DSB threads, all I can say is pay the naysayers no mind

 

[d2mini]

LOL, ok.

But if I do 6" of substrate, being that it's a lighted tank, do i need sand stirrers or anything? Any kind of CUC? I know that if it was an rdsb in a closed bucket I wouldn't need anything. But in this case???

 

[billsreef]

You'll likely get a variety of worms and amphipods settling in the substrate without the need to specifically add anything. They'll be sufficient for stirring

 

[Subsea]

+10 what Bill said on the naysayers. One advantage to the miracle mud sold is the high iron content of this media. I do not replace the mud in my mud filter at 12 years old. It was less than 1" deep when I purchased it used 12 years ago. It has gotten slightly deeper in 12 years and it is spongy to the touch. It is crawling with worms and such. I prefer Ulva as the macro in this section of the mud filter. When I grew Caulerpa is this section, if the holdfast entered the mud a faint odor of hydrogen sulphide was noted. I consider this beneficial as macroalgae biomass includes a high sulfur content. This section is a detritus sink with unfiltered tank water spraying down on a trickle filter that is composed of Bioballs in a wet dry configuration. I suspect your mangroves would want more substrate than 1" deep. In my 135G lagoon, I used a fresh water substrate from Seachem that is high in iron. My intention was to grow true marine plants in a 12" deep sandbed.
Happy reefing,
Patrick

 

[d2mini]

Ok, so what do you think would be the optimum depth of the substrate? 6"?

My only concern is that I have a display refugium that looked great for a while but now it is nothing but hair algae. It took over everything.
The substrate in this tank is about 2" of the Fiji Mud and nothing else.
The mud is dark in color but i can see patches of black against the glass.
Could the mud be the cause? Is it too shallow? Did I do something wrong that I can avoid doing with this tank?

 

[d2mini]

Bump!

 

[slief]

In my main refugium, I run my DSB at 4" and my mangroves do great. My DSB consists of a 2 or so inch layer of mud at the bottom and a mixture of live sand and live rock rubble above that. I've been running it that way for 4 years now and I don't have any sand sifters in there and never disturb the sand bed. This fuge is down stream from my filter socks and skimmer and remains more or less detritus free. I do have relatively high flow through that fuge as my return pump draws from that tank but the tank is setup such that the flow is spread evenly up and down and side to side across the 30" wide x 30" long tank which keeps it calm. That said, I move my mangroves to my display fuge when they get too tall and in the display fuge I only have a 1"-2" deep sand bed. They do fine there too. I will be increasing the size on my display fuge and will likely go to a 3-4" deep bed when I do.

That said, mangroves can do just fine suspended above the bottom of a tank even without sand but they obviously need to be clipped to something or wedged between rocks. What looks really cool is suspending the mangroves well above the sand so that the roots grow down forming little root caves. Eventually the roots will find the substrate and dig themselves in at which point the clips can be removed. My new display fuge will be a 24"x24"x24 60 gallon cube and I plan on suspending some mangroves in there so I can create the little root caves. It's replacing my 24"x24"x12" display fuge..

 

[d2mini]

In my main refugium, I run my DSB at 4" and my mangroves do great. My DSB consists of a 2 or so inch layer of mud at the bottom and a mixture of live sand and live rock rubble above that. I've been running it that way for 4 years now and I don't have any sand sifters in there and never disturb the sand bed. This fuge is down stream from my filter socks and skimmer and remains more or less detritus free. I do have relatively high flow through that fuge as my return pump draws from that tank but the tank is setup such that the flow is spread evenly up and down and side to side across the 30" wide x 30" long tank which keeps it calm. That said, I move my mangroves to my display fuge when they get too tall and in the display fuge I only have a 1"-2" deep sand bed. They do fine there too. I will be increasing the size on my display fuge and will likely go to a 3-4" deep bed when I do.

That said, mangroves can do just fine suspended above the bottom of a tank even without sand but they obviously need to be clipped to something or wedged between rocks. What looks really cool is suspending the mangroves well above the sand so that the roots grow down forming little root caves. Eventually the roots will find the substrate and dig themselves in at which point the clips can be removed. My new display fuge will be a 24"x24"x24 60 gallon cube and I plan on suspending some mangroves in there so I can create the little root caves. It's replacing my 24"x24"x12" display fuge..

Thanks!
Which mud are you using?

 

[slief]

Thanks!
Which mud are you using?

Nothing special.. I got the mud that came out of the bottom of a Fiji live rock holding bins from a local wholesaler. It was probably years worth of accumulation at the bottom of their bins and I used a couple hundred pounds or so worth. I'd liken it to live rock sludge. It was heavy and thick and truly living mud. I had the guy from Miracle Mud trying to get me to use his stuff but I wanted live stuff and I didn't want to have to switch mud out every year or so which is what Miracle suggested.

This was my first deep sand bed and while I can't credit my tanks health on that alone, it is one of the key parts of my system that has helped me to maintain undetectable nitrates in spite of my heavy load and excessive feedings. It is fairly large though at 30"x30" with hundreds of pounds of mud, sand and live rock rubble. All of my water passes through this particular refugium before going to my return pump. It's been 4 years since the DSB went in and I haven't touched the sand/mud bed.

I will look for the LA Fish Guys episode that covered the DSB and refugium setup and post it here shortly.

 

[slief]

Here are a couple parts of my sump/refugium retrofit. This was done while the tank was up and running as I swapped out my previous sumps that day..

Part 5 covers the sump and refugium install including the addition of the mud, sand and rubble going into the new fuge.. If you watch the video and wonder why I put bio balls into the socks.. That was temporary to insure there wasn't any kind of a cycle in the absence of the previous wet dry that had some bio balls and a bunch of live rock. I kept most of the live rock which went into the primary sump and remove the bio balls from the socks over the course of a couple weeks.
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Part 6 covers the mangroves and chaeto.
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