Sand Stirring substrates

[cwrenge]

I have been trying to keep these thoughts private as I would like to gain some empirical evidence to back up my claims. It seems to me as though the substrate should not matter in a properly designed system whether it is a bare-bottom or a deep sand bed system. If the substrate is not allowed to accumulate or "sink" organic material it should work just like a system with no substrate at all. What difference would it make if the substrate was solid? The accumulation is from nutrients creeping into (sinking) the substrate. If this not allowed with proper waterflow it seems to follow logically that the substrate is taken out of the equation entirely.

What I propose and will attempt to verify experimentally is putting the whole sandbed into the equation by having a very subtle flow of water on the magnitude of weeks turnover rate constantly pushing water up through the substrate creating an artificial convection current that will still be lacking oxygen. With an upward flow of water it would resist the gravitational tendency for sand beds to accumulate organic material.

The rest of the system will be the same with high water flow and vigorous protein skimming. I am not so sure of the phosphate removal in this proposal. It might have to follow the frequent water change maintenance schedule, in which case I'm sure Mikey would love to invite me over for a large dinner of small annoying black birds. It seems to me that, like my brain, a deep sand bed is only utilizing a small amount of its true carrying capacity. That and it is not saturated with enough alcohol! I plan to populate the system with schooling fish and then feed them with automatic feeders; to get an idea of the input involved and the resulting processing of the organics. I won't attempt invertrabrates unless I can get the parameters within reason (i.e. <1ppm phosphate, <2ppm nitrate, etc.)

a doo Ron Ron, a doo Ron Ron! Not ready to give up on the concept of DSB's!

All great stuff.... my brain is full of more wonder....as the talk/exchange of sustrates.... what about ..." MUD-FILTERS..." ? if we can actually stir a mud filter....(in operation that is ) would this not be a great benifit to any DSB system....? some how i keep wondering that it would...! and i trust the info thats in this thread.... Gggggggggggge its wonderfull to read what/how you guys go about understanding these things, thanks , cw.

 

[dnjan]

What I propose and will attempt to verify experimentally is putting the whole sandbed into the equation by having a very subtle flow of water on the magnitude of weeks turnover rate constantly pushing water up through the substrate creating an artificial convection current that will still be lacking oxygen. With an upward flow of water it would resist the gravitational tendency for sand beds to accumulate organic material.

How will you be able to accomplish the active water flow through the sand, and still have it lacking oxygen? Do you mean water flow slow enough that the oxygen will be consumed by the time the water gets out of the sand? Doesn't this mean that your sandbed will be "upside-down"? With the oxidizing layer on the bottom, and the reducing layer on top?

 

[aquariumdebacle]

With the flow being so slow very little oxygen will be present but I am thinking of adding coils of tubing before it gets to the bed to make sure the oxygen is depleated before it reaches the bed. I also thought of a nitrogen gas airlift to raise the water from the sump.

 

[RedEyeReef]

Separate question - to what extent would/could true sea grasses (with roots) remove nutrients from a sandbed directly?

My "initially mixed reef" is gradually migrating towards a lagoon biotope, and I was wondering if seagrass in the tank would be able to remove accumulated nutrients in the sandbed before they re-enterred the water column.

What a great thread.

Was this question answered? Would rooted plants pull the nutrients out?

Also what about a DSB with a fish (Sting Ray) that keep the sand stired up enough not to allow detritus to settle in?

 

[dnjan]

What a great thread.

Was this question answered? Would rooted plants pull the nutrients out?

No it hasn't been (at least not yet). I think aquariumdebacle should abondon his current experiment and replace it with a seagrass tank to see if the roots remove nutrients.

 

[hopper]

Thanks Anthony for answering about only stirring the top 1/2" or so. I just put a Tiger pistol shrimp in the tank the other day and he seems to be taking care of this for me.

 

[Anthony Calfo]

Keep in mind that rooted plants will not 'remove' nutrients with their growth, but rather 'bank' them.

in the case of seagrasses or mangroves that are rather stable, albeit slow, growers... its a fine thing.

but in general... given to choose between banking, recycling or exporting nutrients from your aquarium... go for the latter.

For the heavy influx/import of nutrients that we have in most aquariums... a complimentary export mechanism is in order IMO.

 

[Maxx]

At the risk of derailing the conversation....

What is your ideal nutrient exportation method?

Nick

 

[Anthony Calfo]

my ideal nutrient export method is skimming... skimming, skimming, skimming!

For most tanks I favor using two skimmers of different styles... cleaned alternate days to optimize skimmate production.

 

[aquariumdebacle]

abandon is the wrong word I will "supplement" my system with sea grasses. I am not sure if there will be enough flow for the SPS coral as well as too many nutriens. The sea grasses are true plants in that they are angiosperm terrestrial plants that have adapted to the high salinity of the oceans. They will "expport" to the extent that their structure needs energy and nutrients but the amount of energy consumed by a plant is minimal at best and cannot be relied upon to make up for the massive inputs from even a small bio-load from fishes respiring. An upside to grass systems is that the red end of the spectrum is utilized and therfore can be provided with cheap mecury vapor lighting systems.

 

[dnjan]

Restatement of seagrass question

I suppose I should clarify my seagrass question:

Could seagrasses be effective in transporting nutrients out of the sandbed so that they could be removed by periodic pruning of the seagrass? (or more bluntly - Would the roots do anything other than provide anchorage?)

We recognize that many land-based plants remove nutrients from soils. (some do so in such an effective manner that they can no longer grow well)

So - could seagrasses provide sandbed cleaning?

 

[Anthony Calfo]

the minimal pruning of seagrass leaves is nothing compared to the harvest of mass (and nutrients absorbed) via Chaetomorpha, Gracilaria, etc.

They really cannot even begin to compare in a refugium. Very poor nutrient export vehicles (Thalassia) in aquariums.

As for the roots... nope - no magic mojo released that I am aware of. Yep... they can starve themselves in a nutritive bed that becomes depleted (in fact... the lack of adequate nutrition in new sand beds is often why they do not establish). The roots are simply/at best banking nutrients. No export here... just moving the piles around

 

[Forestal]

great info in this thread...thanks Anthony...

I did Dr. Rons sand bed course last year and had a fantastic thriving DSB in my refugium at first, now with my 4th tank setup i think i just got lucky...i was starting to think it futile in seeding...even in a tank i put sand seeded from several sources and live rock for 6 months, no fish...i didnt see the bed thrive (lots o pods tho )

water flow i keep trying to tweak, but am still trying to work out, manifold style still get too much in certain spots, and dead spots in others...ah well, guess i will have to start another tank (just don't tell my wife )

 

[ldrhawke]

You're on the money Anthony......I agree with everything you have said.

I did try a remote bed in my fuge for awhile, but that is even gone now after it caused or contributed to an out break of RTN when I disturbed it pulling out excess rooted macro algae.

Bare bottom is easier to control and it reduces the possible buildup of wastes.

My comment to anyone asking me about why go barebottom is , " What makes more sense in your home? Flushing the toilet or building a compost pile in your bathroom? You could make the compost pile work, but you home would stink like h#ll!:lol:

SKIM SKIM SKIM.......

 

[hawnsky]

okay i just read this thread and its all very good information...i'd like to comment on the remote DSB...about 15 years ago i built what is now called a salt water pond...it was built on my patio/deck at my house in hawaii...the "pond" is 3000 gal has about 3" sand bed(more for asthetic reasons)... it has 2 55gal plastic drums for filters and 2 1hp external waterpumps.... one drum was basically a trickle filter and the other had what i would call a remote DSB... at the time i knew that sand and rock(i used lava rock as it is the base of most of the reefs over there) were helpful to my filtration...the DSB drum was layed on its side in a stand with about a good 12" of sand(got it from the ocean while diving so i guess it would have been called live sand).... the inlet pipe into the drum was placed about 3-4 inches above the DSB and the outlet was placed about 6-7 inches above the bed...the water would be pumped through the drum and back into the pond...it worked/works great til this day...not sure if some would call this a fuge but other than natural sunlight through the somewhat translucient drum there was no other light source...even the pond/tank used natural sunlight...never had/have to dose the tank with anything(i dont remember if much of anything was available) and never had any problems with water quality...i did do water changes but it was ocean water again collected off shore while out for dives(would collect my own fish for the tanks i had at home) but again even with high bioload on the tank no problems...
the tank at the fullest had...
6-7 yellow tangs of varied sizes up to 8"
15 moorish idols schooling nicely (had these for 6-7 years... some died off from other aggression) still have one from about 10 years
3 potters angelfish
several lemon butterflys
three jack trevally( these were actually caught to eat..just had them there to grow a little bigger...they were good)
a few different damsels
and some crabs...cowries and other various inverts
anyways just thought id share...maybe someone could come up with something that would work off of this

 

[aquariumdebacle]

did the same thing...except with a 29 gallon tank. I was going to school in Hilo (not sure how ASH would have dealt with a 3000 g tank! woulda tried if I coulda!) I would SCUBA dive for the rock and sand and use water from the collection buckets (for fish) to add to the system. I also had a "kiddie pool" in the livining room (12"x96") for fish. I kept all sorts of zoo's (until I realized my 8" Spanish Dancer was eating them! Coweries were in on that too I think!) but it is much easier to collect and experiment when you don't have to pay for them (right Krish!) I had two eels in a 15g tank and my Hawaiian friend commented that "everything was living in harmony" until i explained to him how the eels had learn to quickly snatch hermit crabs out of their shells. One man's harmony is another person's brutal life playing itself out.

 

[wave98]

Good to hear from you again Dan. Say, did you ever do anything with your reverse "low flow" UGF. I think that idea is very interesting, and I would love to hear more about it when you get it up and running.

Keep us posted. Now that I think of it, did you have a thread for that, or did it just come up occasionaly in conversation?

Thanks, > barryhc

 

[aquariumdebacle]

Yes, to both questions, got a living situation right now to deal with but I will keep everyone posted. I am working with Jonas for advice and supplies so for now it is "in progress" and I hope to get some pictures posted in the near future (did youhear me Santa? I need a 10 megapixel professional camera!)

 

[Surf]

Reason: all substrates (grain/depth) have the potential to become nutrient sinks in time.

I know we've all been taking that for granted, but are we certain that occurs in aquaria?. Anyone of Shimek's students tried to quantify Sandbed nutrient accumulation in Aquaria?

Lets narrow it to Phosphate for simplicity's sake.

Can anyone think of a way we could measure PO4 this without having the results skewed by infaunal populations? My first thought was to take a sandbed sample, acidify it, dilute it, then measure PO4, but that will also count PO4 bound up in my infaunal populations.

 

[Forestal]

Surf... i took the class a couple years ago, and (going from memory), we looked at various factors at different levels, nitrite, nitrate, sulfur, dissolved O2, phosphate.... sand beds were varying ages and depths, mine was 1 year old in the fuge (low flow) of 6 inches, some had up to 12 cm whatever that is in inches

even in the older and deeper sand beds dissolved o2 was still present and very little sulfur or nitrate was found

i am generalizing, dont want to get specific date wrong (i am looking for the specific data ron emailed us)
but the tanks with higher number and diversity of fauna had less nitrate/phosphates

my problem with the sand beds is keeping the population diverse, seeding it periodically helps, but the fish and hermits are predators, and i seem to always end up witha ton of tube and bristle worms, and not a lot else, altho microscopically would have a lot more...

if i had the time/space, i would setup a tank with rock on a shelf and a dsb super seeded and just let it cook under low light and watch the diversity/growth...

i know ron posted the results in reef keeping will find the link if i can as well as any rough data i had..