DSBs revisited (split The Sump thread)

[Anonymous]

You have to keep in mind that different critters live at different depths, so you don't want to siphon 2" off of the entire bed at once. You may create more problems this way.
The best thing is to remove entire "sections" at a time, say 10"x10" (just throwing an arbitrary number out) and let the tank adjust and stabilize, then repeat the next day, or a few days later - whatever.
The point is, you sand bed is stratified so don't just take off the top layer unless you are going to remove the WHOLE bed at once.

Cheers
Jim

 

[Anonymous]

I've got a DSB that runs about 7" and I have lots of macros, some seagrasses, four HUGE atlantic seacukes and a sandsifting seastar. And the usual hermits and nasarrius snails. But lately I've begun to see more hair algae and even some (shiver) cyano. I figured 1) the filters on my RO unit needed replacing, 2) I should cut back on the iron supplement I add for the macros, and, 3) I needed more circulation, so I added a powerhead and I move it around the tank to blow out areas that don't usually get direct circulation. You guys have me worried. I don't want to crash!!!

I seriously overfeed because of the seahorses and gorgonians, but the inverts and other fish seem to clean everything up, and i change the carbon frequesntly. Am I in trouble?

 

[liquid]

Well Chris, I'm willing to give it a go when I move tanks in a month or two (from my 30 to my 60 gal). The sandbed will come out and I'll either replace it with Starboard or some thin cutting board type material. I see the research and read the all the pages of the above threads and am willing to give it a go. My big thing with letting go of a sandbed is the aesthetics of a tank without a DSB (doesn't look as nice to me). Even the tanks w/ Starboard don't look as nice as a tank with a sandbed. I've got a couple ideas of things I might try to offset the look tho.

I'll probably try the UV as well to give it a go. I can always use the UV unit on my breeding setup if it doesn't pan out.

It's always hard to let go of something that's been in the mainstream for as long as it has. What I find interesting is that I have not seen the biggest proponent of DSB's speak out against what's being discussed. <shrug>

Shane

 

[liquid]

On the flip side tho (playing devils advocate for a minute), Morgan Lidster from Inland Aquatics has had a 20 inch DSB running in a 150 for a loooonnngg time now in his ATS filtered systems and he's having luck with it...choices choices.

Shane

 

[Anonymous]

You can also go with a thin (1") layer of course sand/rubble instead of the dsb. Just siphon it once in a while.

Jim

 

[Anonymous]

This is very interesting. I am going to keep an eye on this topic. I am thinking of tearing down my 90.

The tank had been running fine for well over a year and then I had to move the tank which upset the sand bed. The tank hasn't been the same since.

 

[Anonymous]

Well Chris, I'm willing to give it a go when I move tanks in a month or two (from my 30 to my 60 gal). The sandbed will come out and I'll either replace it with Starboard or some thin cutting board type material.

Where are you getting the Starboard from?

I would like to put a solid piece down. I like to have open area in the tank and think a solid piece would look better.

 

[Anonymous]

Shane,

I look forward to hearing how things go when you move your tank! Please let us know!


What about macroalgae growing out of the sand? What effect, if any, does it have on a DSB? Can it help keep a DSB healthy? Perhaps these are goofy questions, but I am curious.

Chris

 

[Anonymous]

But lately I've begun to see more hair algae and even some (shiver) cyano.

Clare, sounds like the sink is starting to fill up and is beginning to regenerate phosphorous. When phosphates start to become regenerated, algae and cyanobacteria can suck them directly out of the sandbed, so even if you can't measure any phosphate in the actual water, you can still be feeding it to the algae growing on the bed.

This is how algae grows on wild barrier reefs, as well. Phosphate in the water on and being brought to reefs is very oligotrophic, and phosphorous is the most limiting nutrient for algae growth. This means that phosphate regenerated by any organic material trapped in reef structure is what the algae rely on to grow. When not enough of this organic material is flushed away, the reef will start to get into trouble with eutrophication and overgrowth of algae. This is essentially what a deep sandbed does. Instead of flushing this organic material away, it allows it to build up.

I imagine your seagrasses are doing well too, they are a climax community that thrives on sediment porewater geochemistry exactly like what a full sink would be providing. Florida Bay had and incredibly high density of seagrass meadow when the sink was right at full.

I see the research and read the all the pages of the above threads and am willing to give it a go.

Shane, definitely keep us in the loops, but I think as long as you keep your skimming and flow floored, you'll be quite content with what you see.

You can also go with a thin (1") layer of course sand/rubble instead of the dsb. Just siphon it once in a while.

Jim, the idea with these systems is actually to keep the detritus in suspension as much as possible. Any sandbed is going to hinder this and act as a trap. Rubble is a step up, but what pieces of live rock actually allow is for bacteria-generated pressure (turgor) to shed any detritus produced into the water column.

 

[Anonymous]

What I find interesting is that I have not seen the biggest proponent of DSB's speak out against what's being discussed. <shrug>
Shane

He has. It's user error and metals.

Of course that goes against all the "science" he claims to know.

Then there's the distinct possibility, he's afraid to go head to head with Bomber.

 

[Anonymous]

galleon wrote:

...and almost immediate efficient removal by a high power skimmer (which will also offgass orthophosphates) and UV (which will photodegrade organophosphates).

Whoa, back to the future.
UV and barebottom again? That sucks, and is more maintenance than the DSB method. I don't like it, but may be forced to comply. Bare bottom tanks look crappy IMO.

 

[Anonymous]

galleon wrote:

...and almost immediate efficient removal by a high power skimmer (which will also offgass orthophosphates) and UV (which will photodegrade organophosphates).

Whoa, back to the future.
UV and barebottom again? That sucks, and is more maintenance than the DSB method.

Wha? Howso?

 

[Anonymous]

Gotta vaccum it, right?

 

[Anonymous]

Gotta vaccum it, right?

Nah, the idea is to have enough flow in the tank to keep your detritus suspended. You can wet skim it out or collect it with some filter material on the drop to the sump, or whatever. The only time I have ever had to vacuum a barebottom tank is how I knew it didn't have enough flow in the right direction.

 

[Anonymous]

Well, I get some sizeable waste products from my purple tang - when it eats nori the waste is fairly solid. It'd take some serious flow to suspend those lincoln logs. Sorry to depart from scientific talk for a second or two.

 

[Anonymous]

It'd take some serious flow to suspend those lincoln logs.

:lol:

 

[Anonymous]

Now that I've climbed back into my chair, I would think that given a few days, they'd break down enough to easily be picked up by some good strong flow.

Lincoln logs :lol:

 

[Anonymous]

How many gph are we talking about in flow?
Or maybe we should speak about a theoretical tank, say an imaginary 125 gallon tank.
How much flow, do you think, would be required to generate the suspension you're talking about? And how big a skimmer would be required?
Just thinking things out as I plan for my 125 gallon tank.

 

[Anonymous]

Moe, our displays are 135 gallon squares and I run a single Iwaki 70 on each. Its about 1440 gph. The return is at the top of the tank (predrilled, not my choice), so I still get a little bit of detritus settling out (I use 1" flexhose to suck it out every 3 or 4 weeks). If it was near the center of the tank, I'm sure I would get none:

I would think on 125, either an Iwaki 70 or Iwaki 100, with an eductor on either, with the return centered on one side of the tank, would be enough. How long is a 125 again?

 

[Anonymous]

A 125 is 6 feet long, isn't it?
I don't know off hand, as the tank is sitting in a friend's garage.