algae is not able to uptake organic P, organic P must first be converted to SRP by bacteria.
Explain what you mean by SRP.
Algae can access organic phosphate.
It can also convert inorganic phosphate to it.
SRP soluble reactive phosphorous. inorganic p. what good is algae to us then if it is able to uptake organic P? nobody is denying that algae is able to convert SRP to organic. once it is converted to organic again, then what happens to the P? if it keeps going around and more food is going into the system, then there must be an increase in total P.
algae and bacteria are going to grow where the resources are. they are not able to call a place home, then go out foraging for resources. the resource need to be where they are.
Huh? The algae live in water column and take nutrients from it along with any they get from substrate. They are invasive and spread out .Bacteria show up all over .What are you talking about?
we were not talking about the water borne algae and bacteria, we were talking about the algae/cyano growing on the substrate.
Why do you think they are competing? They occupy completely different niches; the benthic organisms serve as an important cog to recycle nutrients so that higher life can use it. This isn't a competition, it's a food web with multiple complementary parts. The main thing that competes with corals, e.g., are other corals, not benthic organisms.
because they are. space and oxygen are not niche resources. they are in the same box, they have to be competing for resources. again, recycling is not exporting. what organism in our systems eat the worms in the substrate that is in the water column? how does the nutrients contained in benthic organism get out of the substrate, whether it is dead or alive? simple question.
The input rate is also way higher in nature, and the net sedimentation rate is vastly higher than in our systems, by virtue of terrigenic input; compared to a coral reef in nature, our organic matter input/sedimentation rate/etc is at least a couple orders of magnitude lower, which is then reflected e.g. in sediment build up rates. Theoretically, if you wanted to replicate natural input rates, then I suppose yes, the sediment would fill up faster. But you'd probably run out of money buying all that food, first.
1) In nature, removal via advection (ie. the sediments being washed away) is a tiny component of the net picture in terms of nutrient removal. The vast, vast, vast majority is recycled in the system, and what does get washed away is replaced by new input. And the benthos itself is not washed away (unless you want to start considering life history and larval migration etc). The types of disturbance that actually do impact the levels of benthic organisms are relatively rare (pretty much just a tropical storm). Much more important is the semi-regular small disturbances such as benthic grazing, larger animals burrowing, etc.
no, the wash away rate is much higher in nature. we ignore the importance of substrate movement in our systems. it is washed out to sea. put a stick in the sand at any beach and see how much of the sand moves in an hour. it is far more than some silly 4 inches that is said to be the optimal depth for a DSB. nature is moving literally tons more sand around than we are. all of this disturbances on a "tiny" tidal scale fail to compare with the massive amounts of movement done when tropical storms come through. how can we ignore this in our systems?
there are several tropical storms a year. in some years over 15. all i am saying is disturb the substrate on a regular basis. it could be weekly or it could be every year. it should match the amount of SRP one wants to provide to the must have organisms.
2) The assumption that the benthos gets overcrowded is false. Even if it reached a space-based carrying capacity (which I highly, highly doubt because our abundances are several orders of magnitude lower than on the reef), it would stay at an equilibrium. And we've been over this oP export mechanism over and over...it is remineralized into soluble forms that diffuse out into the water column where it can be either scavenged by other organisms or removed via artificial filtration methods.
It is all eventually broken down into SRP. And then it's removed. Or perhaps the tank has sand bed grazers, which form another removal mechanism. Once at steady state, the net movement is P out of the sediment due to remineraliztion. The fact that you need a benthic population doesn't change this.
waste organic P, whether it is poo or dead organisms, does not just magically become SRP. bacteria decompose it. so, what happens to the bacteria? how does that bacteria become SRP? all the while more waste organic material coming into the system/substrate. in order for any of that 38% organic poo phosphate to become more SRP, there needs to be bacteria.
I agree, which is why I have been explaining over and over how a functioning benthic sand bed actually works, because it seems benthic ecology is a topic not often discussed in the hobby. What I take issue with are things like the insinuation that because you have more biomass this is necessarily a bad thing, or the incorrect assumption that organic matter or phosphorus will always build up ad infinitum in a sand bed despite well-known export mechanisms.
more biomass=less resources for the organisms we want to keep, or in the case of all of the decomposers the production of CO2. the more waste organic material, the more decomposers, the lower the pH. it is not a coincident that good algae growth and the need for it on an off light cycle go hand in hand. what happens if all of that algae growing in the live sump or the ATS were to be removed. what would happen to the pH? the same bacteria that are feeding the ATS/Chaeto/SRP to be removed later are pouring CO2 into the system.
Not true. Although phosphate tends to be the preferred form for uptake, they can utilize both.
it is the uptake of the inorganic P (SRP) that is most important to us.
I think you mean in order for P to buildup. It does not matter what form it is, because it can be rapidly converted between them. There does not need to be an export of organic P for organic P to not buildup; there just needs to be an export of P after it has been converted, and this is precisely what happens (though as a side note: organic P also diffuses out of the sediment after being excreted)
there has to be an export of organic P. the decomposing organism, the poo, the dead organisms. they just do not spontaneously become SRP. all of these organisms and material needs to be taken into account when discussing P.
No, that is not what happens. Bioturbation and irrigation result in a net removal of phosphorus from the substrate. I think I've said this over and over...
if you mean stirring up the substrate and vacuuming out the detritus, then yes it will result in the removal of P from the substrate. if not, then no. the only person i know of that uses irrigation in the substrate is Paul B. and i think that makes great sense. it goes with what has been said all along.
Once again, ORGANIC MATTER IS NOT BEING HIDDEN IN A SUBSTRATE. Period. To say so, especially if being presented as a supposed "con" of the method, is just flat out wrong. It is being decomposed and exported in a variety of different forms. In a mature tank with a healthy sand bed, presumably at steady state, there is no buildup of reactive organic matter in the sediment.
you have got to be kidding us.
we can see it when we stir up the substrate. what is all of that stuff in the substrate if it is not hidden waste organic material. are you suggesting that all of us are blind? there is nobody reading this that believes that waste organic material is not building up in the substrate. if it wasn't, then none of these magical benthic organism would have anything to eat. this material has to be getting into the substrate somehow.
If by a buildup, you mean the growth of the organisms in the tank, then yes, there is a buildup by definition. But aside from that, there is no "obvious" build up of material in a healthy tank. And if we do count the growth of the system, so what? You have not made a compelling case for the necessity of limiting biomass aside from the point that there is more stuff to die when you have more stuff.
because every organism uses resources and creates waste. whether that is space, the production of CO2, the uptake of O2, or even the use of carbonate. these are all resources that could be put to use by our must have organisms.
This goes back to an old point: we don't know that this detritus is detrimental. We don't know what it is, if it's reactive, etc etc; based on my experience and what I know of the natural ecology of the systems, I honestly think it's non-reactive (possibly refractory, possibly not even organic). I don't remove any and my system is running just fine.
even if it is non-reactive, what good is it doing in the system? it is taking up space. if it is so non-reactive, then why is it so important not to disrupt the substrate if it has not been touched in a while? the longer a substrate has been untouched the greater the risk of a system crash from disturbing the substrate. if it was unreactive, then the longer the substrate has been in place the less of the risk. there would be even less SRP in the substrate than when it was young.
why do you think i haven't? if advective flow or bioturbation did the job that you are saying, then there will not be an increase in waste organic material in a substrates. how would it get in there? what i am suggesting is that bioturbation is actually pushing the waste organic P further down into the substrate. causing a slow migration of P downward into the substrate. allowing more nutrients to be sunk into the substrate.
Because you said so.
nope, because i can see it. it was not there when i put the substrate in the tank. it is there now. where did it come from?
.
i am not seeing any leaving the substrate? this is a pretty easy observation here.
Sunk and slow in a fed reef tank are good things ,IMO.
now it is sunk? i though it was migrating upwards.
Nutrient movement into and out of the substrate and conversions to organic and inorganic phosphate are two way streets not dead ends. I know you are probably going to say you've been saying that right along and shift position,mistate mine or construct a pliable strawman to debate;so, let's skip all that and look at what you have actually been saying all along:
there is not a mechanism either in nature or in our tanks for migrating N and P upwards through our substrates post 156
Not so;diffusion ,bioturbation, advective flow and planktonic biological activity move some up and out to the water
the in fauna help in the slow migration of N and P deeper into the substrate, they DO NOT migrate N and P upwards through the substrate.
post 173.
see above
there is an entire ecosystem all into itself in a substrate. post 183
back to the point i was making much earlier into this post. waste organic material does not magically become SRP. bacterial decomposition is necessary. there is going to be an increase in waste organic material if more waste organic material is coming in from above. the rate of breakdown is not able to keep up. that darn 38% over time problem.
that entire ecosystem that is feeding on all of that material that is migrating upwards from somewhere deep inside the acrylic or glass pane at the bottom of the tank? where is the food for this ecosystem coming from, if not from above? and if it is coming from above and is migrating upwards by all of the process you speak of, then how did it get in there in the first place?
thought we went through how DSB's work. it is the slow migration of nutrients downward through a substrate leaving the upper levels able to bring in more nutrients from the water column. this is how DSB's work, and this is why they "seem" to work so well. Post 228
there is more to it ,see above
what exports P from a substrate? there is not a biological export mechanism for P from a substrate. post 333
see above
then how does it get there in the first place? why would it reach equilibrium? because you say so? i say it reaches an equilibrium when the slow migration of P is stopped because of a lack of resources from the accumulation of waste organic material. leaving all of the waste organic material above to decompose on top of the substrate. just a theory. 
vacuuming of the substrate is the only way to remove P
Agh, While I personally, think siphoning some detritus is useful as a means of export . It is not the only way.
never said it was the only way. in fact i posted a graphic much earlier in this thread showing what types of P the various methods of P removal we use remove.
but none of this would occur if P migrated upwards instead of downwards. 
Post 353
It's a two way street ;not a dead end.
the problem is that there is more going into than out of the substrate. it is a sink. it is not balanced. there have been several graphics showing that it is not a one way street. it doesn't matter if it is just a tiny bit or a whole lot being sunk, the point is that P is being sunk. more is coming in, than going out. something that is easy to observe.
mineralized phosphates is where the problem is. we are ignoring the phosphate solubilizing bacteria again. post 358
If you really think so, why all the blather about one way sinking of organics?If there is psb activity in a reef tank at all ,it would be insignificant IMO.There is nothing offered r to support your position on this point.
because these PSB's are more organically bound P that has to be accounted for. another increase in biomass. IMO these PSB's are why DSB work for their limited time.
i would say most of the P in a newly setup tank comes from the calcium carbonate structures. 355
I say most of it comes from food, waste from organisms and decaying organic matter .
i said from newly setup systems. setup a tank. put some dry base rock in it. let it go with some light and some flow. in a few weeks, there will be algae. where did the P come from to support the algae? do you remember the Southdown days? if the bags were stored outside in the sun and got wet, they would have algae growing in them.
some data on mined sources of LR.
skimming are all going after the inorganic P in the water column. post 411
No, mostly amphipathic organic matter.
the question is how the bacteria and algae that are removed from skimming get their P. they uptake inorganic P from the water column. they are not accessing the inorganic, or organic P from the substrate, only the water column. post 416
No,see above ;they take up organic compounds some of which can be produced in the substrate.
i thought the point of carbon dosing was to lower the SRP levels?
I do have, hopefully, a relevant question to ask, particularly to the DSB proponents as I have not been in this hobby long enough to know. PaulB mentioned Schimek and everyone who's done any research knows he's a big name in this hobby. What happened to him? Why hasn't he been more vocal in the hobby in recent times? Of course I am disregarding his website and the fact that he charges, what, $1 to answer questions. Where is Borneman? Did he ever get his PhD? There are a few other fathers of DSB, for lack of a better phrase, that have fallen off the face of the hobby as well. Why aren't they here to defend in threads like this? Or is the technique now to stay above the fray and let the proxies battle it out?
The reason I think this is a relevant question is because if the original theories of DSB still holds true, why aren't they here to respond?
I will also say that although there is science behind the arguments, no one tank is the same and any specific research can be debunked by just 1 tank, whether it's PaulB's tank or a tank that has a had a DSB running for 10 years. It is a hobby after all, we are here to find out the best way to take care of our tanks, not yours.
lets just say 2007-2008 were interesting years for the reef hobby industry. this is a very touchy subject here on RC. in other places the reasons why Shimek and Borneman are missing can be more openly discussed.
the science is the same for all systems. it shouldn't matter if the system is BB, DSB, SSB, RUGF, it should all be easily explained using the same science. if not, then why not? all anybody can do is give someone all of the information that has gotten them to their decision. give someone the key words necessary to do their own research, at their own pace to see what makes the most sense to them. nobody should be offended for asking dumb questions or for asking for more clarification. we can all agree that if you have a question, that somebody else probably has the same question.
G~
