Observation
 

I've noticed that since removing all that rock and the sand underneath it, My skimmer isn't pulling any gunk from the tank. I'm guessing this implies the rock and sand were contributing a lot in the way of dissolved organics.

Any opinions? :question:

Re: Observation
 

I am leaning to wards the sand contributing to the problem more than the rock. My reason for saying this is that when I moved from my old house to the new one I was emptying my skimmer overflow every day, after removing 85% of the sand and adding a bit of rock I am now emptying it every week or so.

I think because of the sand catching the crud under the rocks as we cannot get enuf flow under the rocks because of the sand to remove the crap. this is allowing it to rot instead of being removed by the skimmer which increases the dissolved organics and phosphate in the tank water.

Steve

Re: Observation
 

Brad,

My three tanks are all sandbed- and skimmer-free. The day before I do water changes, I clean the glass, then turkey baste the rock. There are so many crevices in the rock that crud just flies up into the water column. Some of the crud just falls back into the rock, I'm sure. Some of it falls to the bottom of the tank where I siphon it out during the water change. And some of the crud is pulled into the filter media in the Quickfilter attachments to my powerheads. Cleaning the media in outgoing changewater is an eye-opener, as the water is filthy. It takes several batches of changewater to thoroughly clean the crud from the media.

Based on these experiences, I'd have to say both sandbed and rock harbour lots of crud.

While I have to agree with Bev there Brad, you also must have had to add more top off or new sw to bring level's back up after the removal of all that volume. Maybe this larger than normal water change or top off flushed out the reef pretty good-JMHO though :biggrin:

Re: Observation
 

Hi Brad,

That's about it.
With a lot of life existing in the sand and the rocks, both on and under the surface, you now have a reduced bioload, basically. Detritus is formed by bacteria attaching to the DOC in a high enough quantity to a point that it's heavy enough to fall to the bottom and visible to our eye .
Steve makes a good point, plus the extra room in your tank helps keep the DOC suspended and gets it cleared out more effeciently, too.
IMO.


Mitch

A bunch of reefer's on ReefCental are setting up bare bottom tanks. Although this seems like another reef-keeping-fad the results seem to be quite impressive.

I recently setup an 80g in-wall SPS dominant tank, which some of you on this board have seen. It's bare bottom with lots of flow and my skimmer too hardly pulls out anything, only tea coloured skimmate.

I don't have much to add to this post but I can tell you I will update you in 6 months or so and give you my short experienced opinion on the bare bottom technique.

Jack, bare bottom was actually the way things were run 10 years ago. Then Dr. Jaubert came up with the plenum system in the mid 90's, which evolved into DSB setups. The bare bottom though, had great success. My first reef setup was a 90g BB back in 1994, and it worked well. Reminds me, rock cost about $18/pound then!!

Hey Brad, 10 years ago IS the mid 90's. :question: :question: :question: So bare bottom and DSB were equally used in the '90s I take it to mean??

Maybe this is the bandwagon to jump on? I better remove an inch or so of my sand then. I'm at about 2" and the sand is very dirty.

bare bottom was the standard along with crushed coral. in the mid 90's the plenum showed up and about the same time DSB. plenum and DSB are still two different creatures, one relying on manual removal of waist water the other relying on the sand bed to reduce its own waist. both also included Skimmers as a necessary component.

now that the fads are over people are returning to what was working be for ie. bare bottom tanks.

I think the reason for this is simple, the DSB will not function correctly in a captive system, according to the good Dr, we have only 1/100th of the variety of "bugs" to make a DSB work, and it also tends to trap a lot of crap on its surface in lower flow areas like under rocks (you should have seen mine when I removed it yesterday, top 1/8th inch UUUUGLY the rest was still new). the BB allows for complete siphoning of waist from the bottom of the tank, it allows for higher flow rates along the bottom of the tank and in between rocks keeping junk suspended so the skimmer can remover it.

Steve

how do you get past the unfinished look tho? For me that is a large part of my sand bed (2"-3"). I just cant see me liking the way an acrylic bottom looks. I guess i would have to see a BB up close.

I am getting ready to move my tank so we need to deside this issue now! :)

You have any pics of your BB Jack?

After this thread i did deside to stick with less rock tho. About 135 lbs in a 140. lots of shelves and caves is the plan with an ass load of water flow.

maybe i will cut it down to 1" sand bed too