Any thoughts on Bare Bottom (Berlin) tanks?

[meandean45]

Hello Everyone!
Back again with some thoughts/ questions .
I've been away from the Boards for a couple of years now, and have noticed since I got back that a lot of people seem to be doing the Bare Bottom (BB) thing again. Back in the days when I first entered the Reef keeping hobby (freshwater before that, Man! I'm getting OLD !) BB, or the "Berlin System" was considered the only way to go. My LFS at the time convinced me to "Put some crushed coral in, to keep the calcium and pH up"!!! Needless to say, I had a really good detritus trap, and very soon I had an AMAZING crop of hair algae (and NO, it didn't help with the pH or calcium) In all fairness, he didn't know any more about Reefs than I did, his SW experience was fish only.
So, along comes the craze for DSB's. Yup, I dove in head first. What a PITA it was to remove everything from the tank to get the CC out. I remember it like it was yesterday. However, once I got the sand bed seeded with live sand (Thanks Teri), and everything back into my tank, my algae problem promptly disappeared. I was as happy as a clam at high tide!
Now I'm hearing some dreadful things about DSB's, like that they are detritus traps or may be the cause of OTS, so now I'm beginning to wonder if maybe a BB isn't the way to go.
Questions: Is it harder to keep your' water chemistry balanced in a BB tank?
Will I have nitrogen cycle problems if I do away with all that live sand?
Doesn't the detritus build up in/under the live rock anyways?
Will my Nitrate level build up faster? It did slow down considerably after the DSB matured.
I guess that the $64000 question would be: If my reef's doing well with the DSB, is there any real reason (besides that detritus is more easily removed) that I should remove my DSB?
Thanks to any and all for any advice or input you can give me.
Dean

[Woodstock]

I think the first thing to decide is - do you want a low nutrient water column or a high nutrient water column? Those growing SPS usually opt for the former and go BB with a super high flow rate and super clean water. Others, like myself, who have LPS/softies prefer the DSB or SSB. I've went from DSB, to BB, to SSB (3" fine SB). I am very pleased with my SSB! It is asthetically pleasing, has great NNR properties, and also gives my gobies something to terrorize

[billyr98]

I run BB on my 210g reef... I have no problems with keeping all kinds of corals... My water chemistry always seems to be fine...

[meandean45]

Thanks for the input folks ! I have VHO lighting, so am limited to LPS and soft corals. I guess that BB isn't necessary for me. Woodstock, does a SSB help with denitrification like a DSB does? BTW, the hair Algae problem isn't a problem anymore. My thanks to all for the good advice.
Dean

[Woodstock]

Great to hear your hair algae is gone!

SSB can be NNR but it depends on how fne the sand is. The finer the sand, the thinner the bed needs to be to create an oxyen free place for the bacteria to flourish. I get very good NNR with my 3" sugar fine sand bed

[meandean45]

Thanks Woodstock I always thought that 3" was a DSB! Mine's about 4and1/2" deep Southdown Playsand from Home Depot. I would say that it's "Sugar fine", but that's JMO. Have you given any thought to the Phosreactor ? It's sure doing a fine job for me. Total cost, Reactor, tubing, Ballvalve, and ROWAphos was under $100 from That Fish Place. I'd happily recommend it to anyone, one of the few things I've bought for my tank that works as advertised, and was worth the expense.
Thanks for the reply!
Dean

[cheeks69]

I personally don't like the look of a BB tank but I understand that PO4 will bind to the sandbed in time and eventually be a problem especially with stony corals. I like a sandbed and if eventually if I have to replace I will, it's not a bid deal for me but I only have a 93 gal tank and I love the nitrate reducing ability of a DSB. If I had a much larger tank then I would consider a BB or SSB.

[meandean45]

I agree that I don't like the looks of a BB tank, But was wondering if I'd missed some stunning new reason why people are going back to it. Apparently it may be better for SPS corals, but since I have none, I probably will continue along with my DSB. Myself, I wonder if it's really necessary to replace a DSB if you maintain it. Any thoughts on the need to replace would be appreciated. Thanks.
Dean

[cheeks69]

Any thoughts on the need to replace would be appreciated

Randy Holmes-Farley:

There are, however, other possible sinks for phosphate. One is precipitation onto the surface of calcium carbonate, such as the sand beds that many people use. The absorption of phosphate from seawater onto aragonite is somewhat pH dependent, with the maximum binding taking place around pH 8.4 (see Millero’s link below), with less binding at lower and higher pH values. If the calcium carbonate crystal is not growing, then this process is reversible and the aragonite (or calcite) can act as a reservoir for phosphate. This reservoir may make it difficult to completely remove excess phosphate from a tank that has experienced very high phosphate levels, and may permit algae to continue to thrive despite cutting off all external phosphate sources. If you are experiencing an algae problem, it might even be a reason to want to keep the pH at the high end of normal (say, 8.3 to 8.5) and not at the lower end (7.8 to 8.1). The relationship of CaCO3 to the phosphate cycle is being studied by Frank Millero and his group in relation to the Florida Bay ecosystem (Millero's studies). If the CaCO3 crystals are growing, as they often are in some parts of our systems, then I’d expect some of this phosphate to get buried and locked into the CaCO3 crystals.


A side effect of the adsorption of phosphate onto aragonite may well be the reported impact of phosphate on calcification of corals. The presence of phosphate may inhibit the formation of calcium carbonate crystals via surface adsorption, and this effect may very well be the factor that inhibits calcification of corals at high phosphate levels. If true, then I would speculate that anything that you do to lower the free PO4-- concentration may limit this impact. Such factors would include normal or lower pH (shifting the PO4-- toward HPO4--) and normal or higher calcium and magnesium (because they complex free PO4-- ).

http://www.aquariumfish.com/aquarium....aspx?aid=2276

[meandean45]

Thanks Cheeks!
Interesting quote. I've heard others say phosphate precipitation is harmless if you vacumn off the surface layer occasionally. Thoughts?
Thanks,
Dean

[boozeman]

Aesthetically speaking..theres something about looking at a sandy bottom that just makes the picture complete

[cheeks69]

I've heard others say phosphate precipitation is harmless if you vacumn off the surface layer occasionally

I don't do it and don't recommend it since most of the infauna is in the top layer of the sandbed and according to Dr. Ron these little guys are invaluable to the success of the DSB.

[Yarr]

I have a BB setup in my 100 gal atm and considering what to opt for in my new 180 gal..

BB is great however, the detritus DOES build up under the rockwork but if u get some waterflow under it, it all blows away and gets collected up. that being said.. u only do that to the stuff u cannot suck up with a hose when doing water changes directly from the tank.

IMO with sandbeds it is worthwhile i fu have a decent cleanup crew and good sand sifting critters. If you were concerned about it i doubt there'd be a great problem in stirring up the sand once i a while, portion at a time of course

[corallimorph]

I cut perfect reef-top blocks,unsilicone the top frames lower my "reef-top" in with two high E-strings from an electric guitar(1970 Gibson SG) and resilicone the top frame...all nitrifying and denitrifing bacteria find their niche within the porosity of the natural coral skeleton.

Most corals don't grow attached to sand or glass in the wild.......they grow on a reef structure.-Dave

[corallimorph]