Sand bed

[albert_dao]

You're still not addressing the accumulation of detritus. Nitrate is one of the lesser evils caused by detritus buildup. Other organics/toxins (phosphates, gases) can build up in the presence of large detritus deposits, plenum or DSB notwithstanding.

[Doug]

I would not use the powerhead method myself. Nothing wrong with the riser for allowing the removal of plenum water, {very slowly}, at times. But thats an alternative way and not from the original way Dr. Jaubert published.

Plus I did the course/fine sandbed. If I did one again I would use 4in. of a course media between 3mm to 5mm. This would allow for better water movement through the gravel & plenum. Needs to be deep enough though, with the larger sized grains, so to much oxygen does not penetrate.

Plus I would limit the amount of rock to minimum and elevate what there was. This, of course, is my opinion on running one, as opposed to the plenum systems ran in the 90,s. I have not tested this yet, but others agree with this senario.

The biggest problem is the loss of 6in. of tank space. Of course the sandbed authors figure a plenum is a waste. compared with their dsb ideas. And the bare bottomed aquarists figure both are a waste. I have seen great tanks with all three. Guess it depends on what one wishes to apply to their situation, and the livestock one wishes to keep.

[DJKoop]

Originally Posted by Doug

I would not use the powerhead method myself. Nothing wrong with the riser for allowing the removal of plenum water, {very slowly}, at times. But thats an alternative way and not from the original way Dr. Jaubert published.

The power head was just to get the bed activated. After awhile you remove the power head and the riser.

[Doug]

Originally Posted by albert_dao

You're still not addressing the accumulation of detritus. Nitrate is one of the lesser evils caused by detritus buildup. Other organics/toxins (phosphates, gases) can build up in the presence of large detritus deposits, plenum or DSB notwithstanding.

With the open surface area & the larger particles, one can siphon clean the top portion of gravel easily. I have no idea how one siphon cleans a fine sandbed, unless removing & replacing sections, which many seem to do now.

FWIW, I have run bare in my last few tanks and my new 90 is also. I like the control of detritus removal also. I have rubble in mine and already its trapping detritus.

I have to admit was extremely close to setting up a plenum as I described. I really wanted to see the long term possibilities when done as above. But I cant make myself lose all that space. Not to mention the cost of a decent gravel. If I could find some of the old crushed coral, around the 5mm size, that we used on our undergravel systems, cheap, I may try still.

[albert_dao]

Originally Posted by Doug

With the open surface area & the larger particles, one can siphon clean the top portion of gravel easily. I have no idea how one siphon cleans a fine sandbed, unless removing & replacing sections, which many seem to do now.

Except any portions where you have live rock...

[Doug]

Thats why I mentioned above to limit the rock and any thats used should be elevated. We once talked about doing an sps tank with only a couple of pieces of rock, elevated above the plenum on piles {pipe}, and having most of the sps pieces attached to the glass and overflow. Nothing wrong with then having some extra rock in the sump, as long as it can be kept clean.

The limited use of rock in the tank, will also help relieve caclium demand with the coralline. The 4-5in. of gravel will provide more than enough biological filtration.

Of course this limits types of fish, that require lots of hiding places & rock, like many of the smaller fish & dwarf angels, etc. Once the sps grows, more hidey spots are there. I know if I was a fish, this would not be my favorite habitat, at least not at the start.

[albert_dao]

Originally Posted by Doug

Thats why I mentioned above to limit the rock and any thats used should be elevated. We once talked about doing an sps tank with only a couple of pieces of rock, elevated above the plenum on piles {pipe}, and having most of the sps pieces attached to the glass and overflow. Nothing wrong with then having some extra rock in the sump, as long as it can be kept clean.

The limited use of rock in the tank, will also help relieve caclium demand with the coralline. The 4-5in. of gravel will provide more than enough biological filtration.

Of course this limits types of fish, that require lots of hiding places & rock, like many of the smaller fish & dwarf angels, etc. Once the sps grows, more hidey spots are there. I know if I was a fish, this would not be my favorite habitat, at least not at the start.

:P

... I just don't like substrate.

There, I said it. LOL!

[DJKoop]

When I was planning on using the plenum way I was going to have a 3" bed using Caribsea Seafloor Special Grade Sand. 1-1.7 mm diameter grain. According to them

"This grade of aragonite is specifically engineered for plenum type nitrate reducing beds.

The pore water space created by precision grading also allows maximum pH support and dissolution of calcium carbonate."

[albert_dao]

Originally Posted by DJKoop

When I was planning on using the plenum way I was going to have a 3" bed using Caribsea Seafloor Special Grade Sand. 1-1.7 mm diameter grain. According to them

"This grade of aragonite is specifically engineered for plenum type nitrate reducing beds.

The pore water space created by precision grading also allows maximum pH support and dissolution of calcium carbonate."

Before you make any sort of commitment, I'd ask around on RC and check how many people have long-term success with plenums in a reef tank.

On the other hand, if you're set on plenums, then you're set.

[Doug]

First my comments on plenums are in regards to running them correctly, as Jaubert intended and not the other dozen different ways aquarists have tried, some with success but most failing.

Second if dsb does not work, have a look at the coral growth in Nigel,s FTOTM and Quinn,s tank in the journal forum. Both of these aquarists have run dsb,s for some time. I cant speak for them but both have told me its part of their success.

Point being, they all work if done correct and properly maintained for that particular type of system.