Are Deep Sand Beds, DSBs, dangerous to use in a marine aquarium?

[billsreef]

i am not. the amount of waste produced is very close to the amount of material brought in. that is the point i am trying to make. very little of the material an organism takes in is retained in its mass.

Agreed that a fair amount of what an organism eats is passed through as waste, but that waste also turns into food for other organisms and so on and so forth in fairly tight nutrient recycling. Though in our tanks, (and I think we actually agree on this) there is ultimately an undesired build up that does removal in some manner or another.

that graph was only for the P cycle in the marine environment. here is a graphic showing the entire P cycle. note the amount of arrows going into the substrate, and the number of arrows leaving the substrate.

Still a substantial amount of that P recycling

i am all about stirring up the substrate in an aquarium on a regular basis,

Again I think we're mostly in agreement here.

what from of P is falling from the sky? or do you mean plankton?

Fish food that we aquarist throw in, you've seemingly been ignoring that source of P.

Nutrient supply from fishes facilitates macroalgae and suppresses corals in a Caribbean coral reef ecosystem

G~

Yes, an interesting paper. I'm familiar with their work. I've had the pleasure of attending a couple of defenses that contributed material to this paper

All pictures aside, the ultimate primary source of all types of phosphate in reef tanks is food that we feed. Some may go to and then be released from the substrate, and some goes into organisms and is released. And some goes into organisms and substrate and stays there or is exported if we export the organisms. Some gets exported in various other ways, such as GFO, GAC, skimming, polymeric resins, etc.

Pretty simple and I don't really see how anything more complicated really needs to be involved in our husbandry concerns.

x2

For some reason I can never find a reason to argue with Randy

 

[Fredfish]

Well, I'm not sure exactly what you read, but phosphate does not form bonds with silicate or silica in seawater. If you have the specific link I'd be happy to check it out, but I can't read through 16 pages of posts looking for it.

Well, I don't seem to be able to muster the energy to go back through 16 pages to find the link again either, so I will defer to you on the point. In a way it does not matter. The reality is that phosphate seems to bind to stuff rather easily and precipitate out. In the ocean, it is a scarce resource.

 

[Reefin' Dude]

All pictures aside, the ultimate primary source of all types of phosphate in reef tanks is food that we feed. Some may go to and then be released from the substrate, and some goes into organisms and is released. And some goes into organisms and substrate and stays there or is exported if we export the organisms. Some gets exported in various other ways, such as GFO, GAC, skimming, polymeric resins, etc.

Pretty simple and I don't really see how anything more complicated really needs to be involved in our husbandry concerns.

think of our systems as a chemistry equation. balance for P if P is a constantly added reactant. that is all i am trying to point out. the P has to be removed at a rate that matches the desired trophic level of the system, or it is going to become eutrophic. released into the substrate is not balancing out for P. P is still in the system. P going through an organism is also still in the system. the total amount of P is increasing.

all i am suggesting is to create a balanced system around P. P in equals P out. in order to do this we must understand all of the places that P can hide. just because it is in a substrate between the grains as detritus, in a living organism, or bound to the surfaces of calcium carbonate does not mean it is not in the system and representing an increase in total P of the system.

all of those export mechanisms ignore a huge chunk of where P hides. they are all a day late and a dollar short to the P party. they have to first wait for bacteria to make the P available for them. they can not directly access P from the substrate, where most of it is being sunk.

Agreed that a fair amount of what an organism eats is passed through as waste, but that waste also turns into food for other organisms and so on and so forth in fairly tight nutrient recycling. Though in our tanks, (and I think we actually agree on this) there is ultimately an undesired build up that does removal in some manner or another.

as i was saying earlier. just balance the system using P as the commodity.

food for other organisms means an increase in total P. we get back to the hamburgers again. to support any organism, there needs to be enough hamburgers for them to eat available with an equal amount of hamburgers being released. if more P is coming into the system from us as food, and their is an increase in biomass from the population of support organisms, then the system is not maintaining a constant level of P.

Still a substantial amount of that P recycling

recycled, but the total amount of P is not going down. that is the point i am trying to make. it doesn't matter how it is being recycled, if more P is coming in, then there is an increase in total P of the system. the system is becoming more eutrophic. which could be the goal if the more eutrophic corals are wishing to be kept, but for those keeping oligotrophic organism, this can be fatal.

Again I think we're mostly in agreement here.

probably. disturbing the substrate released the trapped organic P which can then be siphoned out, collected into specialized settling areas, or even trapped in a short term use canister filter for exporting. the point is that this once trapped organic P has been exported from the substrate and is not longer in the system. a major export of P has occurred. a total drop in P has occurred. the source of significant amount of P has been removed.

Fish food that we aquarist throw in, you've seemingly been ignoring that source of P.

:lol: no i am not. the aquarist represents the terrestrial runoff arrow. we are terrestrial, are we not. we are the original source of P for the system. the same as in all of the diagrams. we also need to be realize we are the arrow labeled terrestrial upheaval.

G~

P.S.- another point that i think needs to be made is that waste organic material makes fantastic fertilizer. we use it all of the time in gardening. it is no different than in the marine environment. if fish poo was as big as cow manure, we would be more inclined to see the problem.

 

[Randy Holmes-Farley]

OK so you are worrying a lot about phosphate in the sand and organic phosphate, and have lots of diagrams that you believe support your concerns.

But what exactly is that all telling you to do that folks are not already doing who do not worry about phosphate down in the substrate, or who do not worry abut organic phosphate?

At the end of he day, that is presumably the important take away from this discussion.

 

[Reefin' Dude]

clean up after our pets.

nutrient recycling is not exportation.

clean a substrate on regular basis. how often depends on the trophic state one is trying to emulate.

G~

 

[billsreef]

nutrient recycling is not exportation.

It is when you employ algae filtration and remove the overgrowth of algae as exportation Also protein skimming and GFO can export a quantity of P before it ever becomes sunk in the substrate. With the amount of P (and other nutrients) we keep throwing into our systems, we really do need multiple export mechanisms to prevent eutrophication.

 

[Fredfish]

clean up after our pets.

That's what I have sand bed pets for.

 

[Fredfish]

... With the amount of P (and other nutrients) we keep throwing into our systems, we really do need multiple export mechanisms to prevent eutrophication.

Yup. I don't think anyone is going to argue that. A healthy sand bed is just going to sink some of those nutrients in live organisms and recycle some of the nutrients into very good, live, non leaching, food packets for your corals.

And if you get it right, there will be no need to stir up and syphon your sand. There have been a number of people who have posted here with long term success with a sand bed.

Sand beds are not a miracle product for recycling nutrients, nor are they a must have. Just another thing you can do if you want.

 

[Reefin' Dude]

the P export diagram again

the methods you mention are not going after the majority of the P. they are only able to utilize P that has already been released by bacterial decomposition. in other words, the only way those methods you have mentioned would export P is if there is already a P problem.

some export methods are more effective than others. we must understand what devices take out what. the water column itself is not the source for nutrients. it is just the carrier.

the skimmer is the only piece of equipment we have that actually exports material from the system when it is running, but even that is only able to get a small amount of the P in a system.

that is the point i am trying to make. those methods are not going after the source. they are a step or two down the line. trying to make the bathroom smell better by turning on the fan instead of just flushing the toilet. these methods are just masking the affects of eutrophication. they are not actually getting to the source of it.

removing algae, or any organism is only removing the material that is within the organism at that time. a very little let loss in total nutrients. all of the nutrients needed for that organisms to grow are still in the system. you have not removed any of the nutrients needed for that organisms to grow. the resources are still there in the same quantity as before the algae was exported. even if you remove a huge chunk of algae all of the nutrients that were there to support that chunk of algae are still there. the algae will just grow back, which of course it does since nothing has changed as far as the algae is concerned. the population will bounce back, again showing that the trophic state of the system has not gone down.

That's what I have sand bed pets for.

and this is why our hobby is still in the dark ages.

did you miss the hamburger example a few pages back?

G~

 

[Fredfish]

...
and this is why our hobby is still in the dark ages.

I don't think so. I will take the experiments of Borneman and Toonan over your postulations.

My personal experience with sand beds and nutrient exports suggests that there is nothing wrong with the methods I and others here have suggested.

Just because you fear P does not make it the devil, nor does it put this hobby in the dark ages.

 

[billsreef]

All these methods we mention are essentially the sewer processing plant...the one that gets, and deals with the effluent from that toilet that got flushed

 

[howaboutme]

That's what I have sand bed pets for.

Do your sand bed pets create waste?

 

[Fredfish]

All these methods we mention are essentially the sewer processing plant...the one that gets, and deals with the effluent from that toilet that got flushed

I think that is anthropomorphizing the subject at hand. Fish swim in their own pee in the ocean and have for millions of years. The waste of one organism is the food of another.

N and P in solution are essential nutrients. In sufficiently high concentrations the become a nuisance issue in our tank in that organisms we don't want (algae) start to grow in places we don't want.

As long as you are able to maintain nutrients below levels where they become harmful to the critters you want to keep, they really are not an issue at all. Well, IMO...

 

[Reefin' Dude]

All these methods we mention are essentially the sewer processing plant...the one that gets, and deals with the effluent from that toilet that got flushed

i am not sure we all know how a sewage treatment plant works.

after the solid wastes has been burned and digested the remaining solids are taken away. taken away as fertilizer. imagine that.

a sewage treatment plant does not make nutrients disappear. it just highly concentrates it. it still has to be exported from the system (the sewage treatment plant).

G~

 

[Randy Holmes-Farley]

that is the point i am trying to make. those methods are not going after the source. they are a step or two down the line. trying to make the bathroom smell better by turning on the fan instead of just flushing the toilet. these methods are just masking the affects of eutrophication. they are not actually getting to the source of it.

IMO, you are mistaken about the source. Bare bottom tanks don't magically have no nutrients to export.

But even assuming you are correct, it is certainly incorrect to say that removing phosphate from the water column can only take place once a problem exists.

It is a simple fact that many people can and do maintain appropriate N and P levels in their systems through the means we have discussed and who do not vacuum their sand beds.

So vacuuming may be a fine plan for you, but it is obviously not necessary for all.

If you want to continue to obsess on substrate as the root of phosphate problems, that's fine, and we'll just have to disagree.

 

[Reefin' Dude]

that is the point i am trying to make. those methods are not going after the source. they are a step or two down the line. trying to make the bathroom smell better by turning on the fan instead of just flushing the toilet. these methods are just masking the affects of eutrophication. they are not actually getting to the source of it.

IMO, you are mistaken about the source. Bare bottom tanks don't magically have no nutrients to export.

absolutely, BB tanks have nutrients to export. they are not different than those systems with substrates. the only difference is that the solid waste organic material is visible and not hidden in the substrate. sorry, i thought i made that clear in earlier posts. i am not trying to battle what methodology is better. they each have a trophic level that works best for that methodology, but each can be adapted for the other with the understanding of what the compromises are.

But even assuming you are correct, it is certainly incorrect to say that removing phosphate from the water column can only take place once a problem exists.

you are correct, it will not only take place if a problem exists. if eutrophication does exist, then the water column will not be most efficient place to try and extract P from the system.

It is a simple fact that many people can and do maintain appropriate N and P levels in their systems through the means we have discussed and who do not vacuum their sand beds.

So vacuuming may be a fine plan for you, but it is obviously not necessary for all.

this goes back to what methodology is better suited for emulating which trophic level and why. we do not setup our systems for nutrient export as its primary function. we tend to setup our systems for nutrient collection as its primary function and wonder why we have nutrient problems.

there is not going to be a one setup for all types of systems. we seem to be told this, but this is not true. we need to setup the systems based on what the must have critter needs.

If you want to continue to obsess on substrate as the root of phosphate problems, that's fine, and we'll just have to disagree.

sorry, it is not the substrate i have a problem with. the hobby has a problem with understanding the basics of nutrient flow and what actually happens to solid wastes. sewage treatment plants do not magically make wastes go away, like we want to believe. sewage treatment plants need to export their final dry product. that could be as fertilizer or to a land fill. the material is still exported, it does not vanish. our systems are not any different.

G~

 

[elegance coral]

what makes a substrate work is the slow migration of P downward

Why not upward and out to the water column?

Isn't the goal to maintain low levels of inorganic phosphate in the water? Why then employ a method that adds inorganic phosphate to our water??? Seems kinda counter productive.

If phosphate is basically harmless while it is bound in organic form, wouldn't it be wise to employ methods that remove organic phosphate, and limits its accumulation? Once it's broken down into inorganic phosphate, and escapes into our water, it's kinda to late, isn't it?

 

[GroktheCube]

Just to clarify a couple things, when people talk about "organic phosphate" in this thread, are they speaking about organic molecules containing phosphate, or about living things in general? I've seen a few statements that lead me to believe that some folks are talking about the later, in which case I fail to see why it would be a bad thing, unless of course those living things are pests/parasites.

 

[hedgedrew]

Neen diving snorkeling and walking around reef flats in tahiti. Way more sea cucumbers per square foot than I expected. Tons and tons every few feet. Not sure as aquariats we have enough of them in our tanks.

 

[Randy Holmes-Farley]

If phosphate is basically harmless while it is bound in organic form, wouldn't it be wise to employ methods that remove organic phosphate, and limits its accumulation? Once it's broken down into inorganic phosphate, and escapes into our water, it's kinda to late, isn't it?

It is obviously not "too late" since many fine tanks do not vacuum, but it is wise to export organics, IMO. Methods like skimming, GAC, water changes, and polymer resins all do that. You can add substrate vacuuming to that if you like that method.

Since these often do not keep inorganic phosphate low enough in many tanks, then you will typically need other methods, like growing macroalgae, GFO and other binders, carbon dosing, etc.

How important you think vacuuming is depends on whether you think it contributes only a small fraction of the total inorganic P in the water (say, 5% or less) which I think is likely in my system, or if you think it contributes most of it (which some in this thread seem to believe).