substrate decisions - dsb crashes

[rburn99]

I am trying to decide on my substrate (LFS sold me 80 lbs of Florida Crushed Coral with my 90 - but hey they sold me a w/d for a reef setup so..) but for every argument for any given type there is an argument against it as well.

Sand - lower maintenance but messier looking - blows around
Coral - nice looking but have to vacuum - rough on bottom dwellers
dsb - magic nitrate remover but will crash eventually (according to this link)
http://www.marineaquariumadvice.com/for ... .php?t=755

I'm thinking there's no right answer here. I really could do without having to do water changes in the tank just so I can chunk around in the gravel with my siphon tube to clean it... especially if the LR will reduce the need for water changes.. not to mention the sump would be much easier to draw the water from. But the sand systems I've seen do look a lot grungier than the crushed coral ones.

Sorry.. got way off track I was originally just going to ask about DSB's crashing. (as the author of that link states) I'm wondering why I haven't heard more about this.

Robb (currently a noob)

 

[ChrisRD]

There are many examples of DSBs working long term, so I don't buy the idea that they are necessarily doomed to failure.

That said, personally, I don't prefer them (never had nitrate issues with/without one) and I think any of the popular options (barebottom, shallow sandbed, deep sandbed, crushed coral, etc.) can work if properly maintained.

There are just too many successful tanks out there using those methods to deny that they are viable options (IMHO). Just depends on how you want to run your system.

What do you want to keep in your tank?

 

[rburn99]

Well I used to have FAIWLR (fish and inverts hehe) about 9 years ago. Except for the Great Sea Apple Incident of '93 it was a very enjoyable tank. This time I would like to add some coral. Not much... I don't want a coral showcase. Maybe just a few mushrooms or something. (will require more research as to what exactly). I guess if you're even going to have just one coral it's going to severely shorten the list of available fish though. Flame Angel and Coral Beauty were a couple I had before that I would like to have again. I understand Flame Angels can eat corals though. I think a school of something would be awesome. Is that possible in a 90?
I had crushed coral then also. No problems except had to chunch around with the siphon tube during water changes to get rid of the detritus that would work it's way down in.

 

[ChrisRD]

Personally I don't like crushed coral for the reason you mentioned - it needs to be syphoned reguarly. The finer sands don't seem to collect crap nearly as fast.

Keep in mind that good strong circulation helps keep detritus suspended so it can be filtered/skimmed out rather than collecting in your system. IMO periodically "storming" your tank with a powerhead or turkey baster is also helpful in reducing detritus build-up in your sandbed and rockwork.

As for fish, there are a lot of small, colorful, reefsafe fish that could be kept in groups in a tank that size. Do some research on what you might like to have (check the link in my sig for our reading list) and then ask specific questions about species compatibility, or maybe just post a proposed stocking list in the main discussion forum where some of most experience folks can get a look at it for ya.

HTH

 

[Anonymous]

The debate about sand is calming down a bit, but it is still hot.

My take:
DSB's were taken to be some kind of miracle filter by many people. The thought was you could set up a DSB and then your tank would be fine forever with very little maintenance. That seems to be a wrong idea for several reasons, the most obvious being that there is no such thing as 100% recycling. A DSB is a filter like any other and over time the sand will collect and fill with detritus which basically rots. At some point, the sand bed will fill up and start re releasing nasties into the water HOWEVER the rate it fills and the rate it re releases and completely unknown. So, it may take 20 years for the bed to fill, or it may take two years. Sand may blow around in strong current. Some advocate storming, cleaning, vacuuming or replacing a sand bed every few years. Others are saying bare bottom is the way to go because you can have massive flow the keep the detritus in suspension and you don't have any detritus collecting in the sand and rotting. Still others like sand and are going with short sand beds because they are easy to clean. There are even other ideas like casting sand into the bottom of the tank so it looks like sand but doesn't collect detritus or blow away, and more that are growing zoa's or gsp all over the bottom.

If I were setting up a new tank for long term I would do bare bottom, cast sand bottom or short sand bed - I haven't decided and prolly won't for two years or so.

If I knew I was moving in two years (or wanted to keep sand bed needing animals) and would have to break the tank down I wold use a 4-5 inch sand bed because in the short term, they make great filters.

Wow, long paragraph.

 

[ChrisRD]

If I were setting up a new tank for long term I would do bar bottom, cast sand bottom or short sand bed

Ditto.

 

[Anonymous]

I am pulling out my DSB after 3 years. I am haveing for the first time hair algae problems. I think my DSB has befome saturated and is releaseing back into the tank. I am also planning on uping my flow and my DSB already gets a little stired up by my pumps and my clown fish. I will be Bare bottom when I am done and I plan on running that way.

 

[Don424]

Have you thought about this concept.....crushed coral on a UGF with REVERSE flow?

 

[rburn99]

Don,

That's what I had in my F0 tank years ago. There was a steady flow (don't remember how much) through the bed but it didn't stop the detritus from settling down in the coral. I still had to chunk around in it with the vaccuum (and got some nasty stuff every time). I don't know how much you'd have to push through to keep detritus from settling but I imagine it would have to be enough that the crushed coral would be 'dancing' around like popcorn. :lol:

I think I'm going to go with crushed coral but before I put it in I'm going to make up a 1/2" dia. cpvc grid (drilled with 1/32 holes) that covers the bottom and then up and over in the back corner... in the style of CPW (although I'm not going to use it as a CPW). When I do water changes I will just open the valve and siphoning water will rush down through the bed and out (flushing it I hope). If it doesn't work I just won't open that valve any more and go back to doing water changes the way I used to.

Also, to help keep the detritus suspended I am going to use a Wave2K wavemaker.. supposed to provide incredible amounts of flow.

 

[ChrisRD]

Robb, please let us know how your idea works out with the piping - sounds interesting. I would guess that you might have to stir the bed around a bit with a stick or something while it's draining to get all the crud out.

 

[Don424]

Robb...........thanks for replying. As for keeping the crap in suspension, I'll share with you what I had for awhile that really worked. I had a custom made internal filter(got rid of it ....too much maintenance) that had 2 Rio pumps in it that were pumping over 600 gph each. Both of the pump outflows were attached to a spray bar(1/2 inch pvc with holes drilled every 3/4 inch) which went across the rear top of the tank and the onther on the side/top. It provided tremendous circulation and suspension of the crap. You might give some thought to that type of an arrangement for your tank using a mage or rio hooked up on the wavemaker.

Keep me abreast of how things develop and I will with you.

Best regards,
Don

 

[Deep Blue]

Take this for what its worth, my "gut feeling" is that if you keep your tank nutrient low and expect to change 1/2 of the sand bed every 5 years or so that they are a superior setup.

Perhaps lower maintenance on a "week to week" basis and higher maintence on a intermitten long term interval basis.

 

[Anonymous]

I kept a Simple UGF system for years with very little maintenance.

Have you looked into a fluidized bed filter? The idea is to kinda have the benefits of a UGF with water flowing through a calcium carbonate source, but external to the tank so the media can be replaced if necessary.

In my current 55g I use silica play sand 1" deap, an in tank refugium, and an external sump/refug/with a filter box. When I use crushed oyster shells for the filter media, calcium rose to and has stayed at 400 ppm. I am now thinking of doing a DIY fluidized bed filter with the oyster shells. That would eliminate any of the problems of the sump/refug. Like floods and the pain of cleaning the media every week or two.

Just a thought.

Bob

 

[ChrisRD]

Have you looked into a fluidized bed filter?

I've run a fluidized bed on fish-only marine tank. It's really not a good application for this type of filter - they are at their best on live-planted freshwater tanks. They suffer from the same limitations as many aerobic filters - they nitrify well but do not provide for any denitrification which can eventually lead to a nitrate problem. As with anything, there are ways to make it work, but IMO it's a poor choice for a reef tank.

 

[Anonymous]

I kept a Simple UGF system for years with very little maintenance.

Have you looked into a fluidized bed filter? The idea is to kinda have the benefits of a UGF with water flowing through a calcium carbonate source, but external to the tank so the media can be replaced if necessary.

No reason I can think of to have a UGF or a fluidized filter on a reef tank.

In my current 55g I use silica play sand 1" deap, an in tank refugium, and an external sump/refug/with a filter box. When I use crushed oyster shells for the filter media, calcium rose to and has stayed at 400 ppm. I am now thinking of doing a DIY fluidized bed filter with the oyster shells. That would eliminate any of the problems of the sump/refug. Like floods and the pain of cleaning the media every week or two.

I think you should just remove the media.

 

[LCGoldman]

.... I really could do without having to do water changes in the tank ...
Robb (currently a noob)

Got to do water changes... "Dilution is the Solution to Pollution"

 

[rburn99]

ICG,

You took a piece of my sentence and made it out of context. I didn't say I could do without having to do water changes... I said I could do without having to do them just to be able to chunk around in the substrate with a siphoning vaccuum. In other words, I would prefer not having to do a water change when it wasn't necessary just because I needed to do something else (ie: vaccuum the substrate).

 

[LCGoldman]

Sorry Robb... please forgive me.

 

[rburn99]

Is not a problem Lonnie
It's an easy thing to do when reading/writing words without inflections.

 

[Unarce]

Hey Robb, here's my sand bed template:

If you were to set up a reef tank with high current, than there would be a lot of bare areas if you had a SB less than an inch high. 2-3 inches is the absolute best way to go. It would be incorrect to claim that a sand bed provides 'more capacity to nitrify and denitrify' simply because it's deeper.

"As much as 70 to 90 percent of the overall denitrification was located in the uppermost centimeter. The remainder was found at 1-3 cm depth"

-T.K. Anderson 1984 "Diurnal Variations of Nitrogen Cycling in Coastal, Marine Sediments."

"anaerobic habitat can be as small as 1mm, that aerobic and anaerobic bacteria essentially coexist, and that as little as 0.08mm distance is sufficient for nitrification and denitrification to take place simultaneously."

-Ecology and Evolution in Anoxic Worlds. Oxford University Press, Fenchel, T. and B.J. Finlay. 1995.

The misunderstanding is that areas with low levels of oxygen are a must for denitrification. Since we now know that aerobic and anaerobic bacteria exist together in the upper portion of the SB, than the heavy oxygen levels of our tanks would not be a factor. It's unlikely that denitrification will occur in the deep areas of a DSB, especially if nitrates never reach it in the first place.

I'd also like to point out that a deeper sand bed doesn't necesarily equate to more biodiversity of life. A shallow sand bed of numerous grain-size will create a number of different environments housing more life than a DSB.

I keep grain sizes that range from sugar-grain to large crushed coral. The larger grains help keep finer sand from blowing around. :wink: