Let's Talk About ~Algae Control~

[DonW]

Man thats cool!, Ive got to see this tank that has no detritus "ever". If your snails are happy and healthy in a nitrate free enviroment they will breed very frequently. You will see many on your glass especially in the morning. These young snails do not live to be adults, if they did we would all have millions of adult snails. The planted adults live to become large bulldozers that eventually have to be removed.

Don

 

[wave98]

Man thats cool!, Ive got to see this tank that has no detritus "ever". If your snails are happy and healthy in a nitrate free enviroment they will breed very frequently.
Don

You know full well Don, that I currently have a nitrate level of 15 ppm. That may be why I have only seen a few juveniles so far.

You will see many on your glass especially in the morning. These young snails do not live to be adults
Don

Really Don, and why is that "pray tell"?

The planted adults live to become large bulldozers that eventually have to be removed.
Don

Boy Don, that is really a good one, I suppose that applies to Nassarius snails as well? Probably blue legged hermits too, right?

You really crack me up!

Happy reef keeping anyway Don! Wave98

 

[DonW]

Wave98,
I couldnt tell you why the babies die. I dont know how big a blue leg hermit or nassarius get. I only have a few astrea and turbos, 250 give or take. I purchase dime sized and send them to my suffer in my kids softy tank when they reach an inch or two. My tank is BB sps, with ok flow and detritus just like everyone elses with animals. Nassarius like sand and crabs bother sps. One thing that I've learned in my short 11 years in the SW hobby is that if its alive it contributes to the bioload. If you dont do something to counteract even the snails your going to have problems such as nitrates and algae.

Don

 

[mojoreef]

Well, here's a novel idea. Keep a good population of snails and crabs in the tank, to keep your visible algae under control.

Well finding something to eat a problem that is consistant isnt really a fix, just kind of a bandaid. Another novel idea would be to reduce or eliminate the food source for the algae?? (N,P) that way if cant grow if it cant eat??

Well, firstly, they poop out 15% less than they take in, and that is a net benefit

Well I guess that is a gain but still doesnt fix the problem? Its a house of cards kind of thing when you dont just fix the issue of hand but then choose to add one thing to fix anothers short comings.

Really folks we are just talking about waste/detritus removal here. If you compile all the different methods you come out with two basic models. Those that remove it prior to breakdown/rotting and those that lock it up in cycles and organics (kinda like composting).
Two things always worry me about the second method. One is that I have no control over it, biology/mother nature controls it. The second is that when you build up a house of cards> dsb, which relies on bacteria which rely on critter for transport, which are always in a state of flux, which relies on more tempermental enviroments, then you add calurpas or simular, which relies on light, and constant supply of nutrients and is prone to sexual and so on, one event such as a power outage or heater break down or mass spawning and so on and the house of cards comes down.

On a side note here I have a whole bunch of flow and still have spots with detritus, I think it would be pretty hard to be detrius free.


mike

 

[Scooterman]

Mike, In smaller tanks would it be reasonable to say even with great flow designs you would probably need to remove waste at a higher rate than say a tank twice as large? I would assume in each case the tanks were loaded the same amount of stock just maybe the bigger tank had more LR more water? I'm starting to think one algae problem common is the fact that we really don’t realize that the average tank will require more husbandry than a large 4/5 hundred & larger tanks? Is there a proportion difference because of the massive amounts of water as compared to LR & fish & corals in these tanks? If this is true then maybe one of the problems I see with so many people having algae problems is the fact that they think their husbandry is up to par and there has to be something else to blame, I think I'm the first to say I was guilty of not cleaning my tank as often as it took to be algae free, if indeed I would of done twice the husbandry it would of never had algae problems. I noticed that if I blew off the rocks daily, vacuumed weekly along with a few other minor chorus it was pristine, If I dropped the ball just even a week It showed. So to sum it all up are we underestimating our tank husbandry requirements according to all of our knowledge maybe trying to compare what we have to some of the rather large super system we read about & see here, something we don't grasp all of the details involved in these systems that reduce your husbandry requirements?

 

[Scooterman]

WHEW, that was the most I typed in a while please excuse me LOL!

 

[DonW]

Scooterman,
I couldnt agree more. Modeling husbandry by comparing my tank/system to Mojo's just would'nt work.

Don

 

[Boomer]

I just saw this

does the oxygen level have anything to do with this pH condition in the sand bed?

Yes and no. O2 has no direct effect on pH but it is the lack of O2 that allows things like facultative dentrification to take place, where the pH can get low. However, you do not have to have a low oxygen level to have a low pH in the SB. Orangics break down by various reactions and bacteria which produce CO2, which lowers pH. O2 can still be at normal levels, ie., undergravel filters in fish tanks

 

[wave98]

Yes and no. O2 has no direct effect on pH but it is the lack of O2 that allows things like facultative dentrification to take place, where the pH can get low. However, you do not have to have a low oxygen level to have a low pH in the SB. Orangics break down by various reactions and bacteria which produce CO2, which lowers pH. O2 can still be at normal levels, ie., undergravel filters in fish tanks

Thanks Boomer, I almost got that whole thought. Curiosity here though, in a case where the O2 is still at a normal level, wouldn't that be because of water flow keeping the O2 "up", and then wouldn't that same flow be removing a considerable amount of CO2 build-up?

In any case, we need the low oxygen condition to allow denitrificaton, which means the organics breaking down, and bacteria producing CO2, reducing pH, and then heaven forbid now, this is going to cause our araganite in particular, to begin releasing it's chemical compounds.

So we start getting calcium and carbonate alkalinity buffering and then also the dreaded leaching ( or release ) of phosphate as well. Does this mean that we cannot gain the "positive" buffering capabilities from the substrate without simeltaneously suffering from the additional phosphate as well?

If so, then just how bad is this phosphate problem? Is it so bad that we just can't handle it in a substrate system of any kind, or is there some better method for keeping a substrate in a reef system?

You may have answered this question many times before, but this is what I am here to learn. Your response is highly appreciated!

Wave98

 

[Boomer]

in a case where the O2 is still at a normal level, wouldn't that be because of water flow keeping the O2 "up", and then wouldn't that same flow be removing a considerable amount of CO2 build-up?

Yes and No

CO2 is heavier than either water or O2. Your O2 is coming from mostly ambient air and most of the CO2 is being created right there. O2 does not change the pH but CO2 has a direct impact on pH lowering it.


which means the organics breaking down, and bacteria producing CO2, reducing pH, and then heaven forbid now, this is going to cause our araganite in particular, to begin releasing it's chemical compounds


Yes and No

This will only take place in a new system with fresh substrate for the most part. As soon has a fresh carbonate substrate gets hit with seawater a carbonate called High Magnesium Calcite begins to grow on the surface of the fresh carbonate/Aragonite, which also pull down P. If now the pH drops just a tad the Ca, Alk, pH and P rise but actually came from the original water, so there is not net gain.

If the pH continued to drop there is usually a partial dissolution and a re-precip taking place at the same time. This can/could turn the SB into a solid or clumpy mass. Once a system has been established for a couple of months the SB dos about nothing for Alk, pH, Ca, Mg or P as it gets coated with organic slims and bacteria which are impervious to acids, so there is no dissolution, unless the pH gets down even farther, often followed by clumpiness.

In short SB do about nothing for P, pH, alk or Mg and Ca. P is controlled mostly by YOU . foods, additives, organics , animals, plants, etc.. The only time P really becomes an issue, with the dissolution of carbonates, is for those that run Ca reactors.

or is there some better method for keeping a substrate in a reef system?

If you are worried about a substrate SB then do not use aragonite but rounded quartz sand grains. The real purpose for a aragonite SB is not for buffering, pH or any control of chemical reactions. Its purpose is to supply a more natural SB that better suits the micro-meiofauna and has a better porosity of bacteria.

 

[wave98]

Its purpose is to supply a more natural SB that better suits the micro-meiofauna and has a better porosity of bacteria.

So, Araganite might promote nitrification and denitrification with better porosity, but this is a trade off relative to clumping and or something else that is better handled by the rounded quartz sand? :eek2:

Wave98

 

[Boomer]

Yes and then one will pose the question what about the quartz raising the silica and causing diatoms...pretty much another myth. Clumping is usually not an issue and most clumping is not due to this at all but bacteria producing glues cementing the grians together. I would stick with Aragonite, as well rounded quartz grains are not common as one would think. Smooth grains are important, as they due not tear the mico-meiofauna animals

and it is Aragonite not Araganite

 

[wave98]

OK Boomer, so the quartz isn't going to dissolve, so it it isn't going to "leach" silica or anything else either, right? If so, then does relative lack of porosity necessarily cause it to "fall down" significantly in regard to supporting our beloved bacteria?

Thanks by the way for the spell check. I'm really a stickler about that myself. I was doing it right until the other day, when several people got me off on the wrong track! ( It's never my fault! )

Wave98

 

[Boomer]

Many people use qaurtz sand with no problems

 

[wave98]

Thanks Boomer; It seems like you were editing your post while I was replying , and it might appear confusing. I think I might be with you here, so let's see how it turns out.

If you are worried about a substrate SB then do not use aragonite but rounded quartz sand grains. The real purpose for a aragonite SB is not for buffering, pH or any control of chemical reactions. Its purpose is to supply a more natural SB that better suits the micro-meiofauna and has a better porosity of bacteria.

I am not yet worried about running a substrate system. I am currently insisting on running one however, and it is everybody else that is having a screaming fit about the tragic downfalls of running any kind of substrate. Many of them, I believe are under informed, or over "mythified". ( try a spell check on that one! )

So back to the matter at hand, are we back to Aragonite? I am interested in trying to resolve some of the pitfalls of running substrate systems, and while it may not be the easiest task, I am willing to experiment with it to see what can be done. What do you see, as the "non-myth" diffuculties with substrate systems, and what if any best solutions there are to maintaining or extending the life of one.

Thanks again! . . . Wave98

 

[wave98]

You are outrunning me at the keyboard Boomer, it is getting hilarious!

Wave98

 

[mojoreef]

Mike, In smaller tanks would it be reasonable to say even with great flow designs you would probably need to remove waste at a higher rate than say a tank twice as large?

Yes and No, lol with a large tank you get more dillution with more water, but then you also have alot more bioload creating detritus, so...yes and No.

So to sum it all up are we underestimating our tank husbandry requirements according to all of our knowledge maybe trying to compare what we have to some of the rather large super system we read about & see here, something we don't grasp all of the details involved in these systems that reduce your husbandry requirements?

I have run many sized systems, Personally I think the whole husbandry issue is relative. It takes me alot longer to clean my glass, I produce more detritus and so on and so on. I think husbandry has to be a common sence approach, if you allow detritus to build up your going to have issues, what the husbandry schedule is depends on the ammount of inputs.Ex: you have a big tank and you feed alot, your going to have more work to do.


MIke

 

[Boomer]

What do you see, as the "non-myth" difficulties with substrate systems, and what if any best solutions there are to maintaining or extending the life of one.

The accumulation of unwanted substances that do no go anywhere, like heavy metals. Solution, replace SB with new SB every couple of years

 

[mojoreef]

some are linkable some arent. I will post the abstract from the unlinkable ones for you.
Aquacultural Engineering
Volume 27, Issue 3 , March 2003, Pages 159-176

Water quality and nutrient budget in closed shrimp (Penaeus monodon)
Dhirendra Prasad Thakurm4.cor*m4.cor*, mailto:[email protected]:dpthakur@hotmail .com, a, b and C. Kwei Lina

Nutrient budget revealed that shrimp could assimilate only 23–31% nitrogen and 10–13% phosphorus of the total inputs. The major source of nutrient input was feed, shrimp feed accounted for 76–92% nitrogen and 70–91% phosphorus of the total inputs. The major sinks of nutrients were in the sediment, which accounted for 14–53% nitrogen and 39–67% phosphorus of the total inputs.

Water Research
Volume 36, Issue 4 , February 2002, Pages 1007-1017

Phosphorus Budget as a water quality management tool for Closed aquatic mesocosms

Awesome Article in how the St. Lawrence Mesocosm at the Montreal Biodome have dealt with nitrates and phosphate reductions. It seems that they have tried for the last ten years to try to remedy the amounts of phosphates and nitrates in their setup. After close controlled experiments and nutrient removal they have developed what they feel as the only reliable reduction process and that’s using Large mechanical filters and cleaning them regularly and sucking out the detritus with an underwater vacuum cleaner.

Advances in Environmental Research
Volume 6, Issue 2 , March 2002, Pages 135-142
Field measurements of SOD and sedimenthit2hit2 nutrient hit1hit1fluxe****3hit3 in a land-locked embayment in Hong Kong
K. W. Chaum4.cor*m4.cor*, mailto:[email protected]:cekwchau@i net.polyu.edu.hk

Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong

It is logical that sediments in eutrophic water may contain enormous amounts of phosphorus existing in both organic and inorganic forms. Under aerobic conditions, a thin aerobic layer with a thickness of a few millimetres covering the sediments exists, which has been determined to be one of the factors contributing to the assimilation capacity of phosphorus. (Promeroy et al., 1965) When the condition changes to anaerobic, the ferric compounds are reduced and the sorption capacity substantially decreases. A free exchange of dissolved substances between the sediments and the overlying water takes place. Under such conditions, phosphorus will be gradually released into the overlying water.
Compared with phosphorus, the process of nitrogen release from sediments is more complicated since it involves the inter-conversion of a larger number of nitrogen species. It was noticed that ammonia nitrogen was, among others, the key form of nitrogen released from the sediment, which agreed well with results reported by Boynton et al. (1980). The release of a high concentration of ammonia nitrogen from the sediment is the result of the decomposition of organic nitrogen, which previously accumulated continuously in the sediment. The concentration of nitrate-nitrite nitrogen was found to be low since it can be released from or absorbed into the sediment, depending on the concentration gradient across the interface between sediment and water. When the external nutrient loadings or sources were gradually decreased and removed from Tolo Harbour, sediment previously enriched with nitrogen could still release sufficient nitrogen quantities to support the growth of plankton and hence improvement of water quality could not be achieved immediately.
It is also noted that the sediment release rate measurements are of the same order as those computed independently from a diagenesis model (Lee and Feleke, 1999).

Water Science & Technology Vol 42 No 3-4 pp 265–272 © IWA Publishing 2000

Non-steady variations of SOD and phosphate release rate due to changes in the quality of the overlying water
T Inoue*, Y Nakamura** and Y Adachi***
* Department of Maritime Systems Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
** Port and Harbour Research Institute, Ministry of Transport, 3-1-1 Nagase, Yokosuka, 239-0826, Japan
*** Department of Maritime Systems Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
--------------------
ABSTRACT
A dynamic model, which predicts non-steady variations in the sediment oxygen demand (SOD) and phosphate release rate, has been designed. This theoretical model consists of three diffusion equations with biochemical reactions for dissolved oxygen (DO), phosphate and ferrous iron. According to this model, step changes in the DO concentration and flow velocity produce drastic changes in the SOD and phosphate release rate within 10 minutes. The vigorous response of the SOD and phosphate release rate is caused by the difference in the time scale of diffusion in the water boundary layer and that of the biochemical reactions in the sediment. Secondly, a negative phosphate transfer from water to sediment can even occur under aerobic conditions. This is caused by the decrease in phosphate concentration in the aerobic layer due to adsorption.

http://www.terrapub.co.jp/journals/...03/55030463.pdf

http://chemed.chem.purdue.edu/gench...h10/group5.html

http://www.bact.wisc.edu/microtextb...OtherAssim.html

Jaubert J., Marchioretti M., Priouzeau F., 1995. Carbon and calcium budgets in a semi-closed coral mesocosm. In: Proceedings of the 7th International Coral Reef Symposium, 289-293 (Boston, USA: April 1993).

Jaubert J., 1989. An integrated nitrifying-denitrifying biological system capable of purifying seawater in a closed circuit aquarium. Bull. Inst. Océanogr. Monaco. 5: 101-106

Boudreau B.P., Jørgensen, B.B., 2000. The Benthic Boundary Layer: Transport Processes and Biogeochemistry. Oxford University Press © 2000

 

[mojoreef]

Aller, R.C. 2000. The Benthic Boundary Layer: Transport Processes and Biogeochemistry, Ed. Bernard P. Boudreau, Bo Barker Jørgensen, Ch. 11. Transport and Reaction in the Bioirrigated Zone, Oxford University Press © 2000
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Marine Pollution Bulletin
Volume 20, Issue 12 , December 1989, Pages 624-628
Alteration of phosphorus dynamics during experimental eutrophication of enclosed marine ecosystems*1
Kenneth R. Hinga
Marine Ecosystems Research Laboratory, Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
Available online 7 April 2003.
Abstract
A 28 month eutrophication experiment was conducted in marine mesocosms at the Marine Ecosystems Research Laboratory of the University of Rhode Island. Each mesocosm contained 13 m3 of seawater and a layer of benthic sediments transferred from adjacent Narragansett Bay. Nitrogen, phosphorus, and silica were added daily to the mesocosms.

The paper examines net exchanges of phosphorus between benthic sediments and water column during the experiment. At low loading rates the regular annual pattern of phosphate concentrations is still evident but the amplitude of the pattern is magnified. At higher loading rates the annual pattern is lost and the effectiveness of the sediments to act as a `buffer' to water column concentrations is reduced. In some cases the nutrient loading caused a release of phosphorus from the sediments.
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Author/Editor/Inventor
Hopkinson Charles S, Jr [a]; Giblin Anney E; Tucker Jane; Garritt Robert H.
Institution
[a] Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA, 02543 USA.
Title (English)
Benthic metabolism and nutrient cycling along an estuarine salinity gradient.
Source
Estuaries. 22(4). Dec., 1999. 863-881.
Abstract
Benthic metabolism and nutrient exchange across the sediment-water interface were examined over an annual cycle at four sites along a freshwater to marine transect in the Parker River-Plum Island Sound estuary in northeastern Massachusetts, U.S. Sediment organic carbon content was highest at the freshwater site (10.3%) and decreased along the salinity gradient to 0.2% in the sandy sediments at the marine end of the estuary. C:N ratios were highest in the mid estuary (23:1) and lowest near the sea (11:1). Chlorophyll a in the surface sediments was high along the entire length of the estuary (39-57 mg chlorophyll a m-2) but especially so in the sandy marine sediments (172 mg chlorophyll a m-2). Chlorophyll a to phaeophytin ratios suggested most chlorophyll is detrital, except at the sandy marine site. Porewater sulfide values varied seasonally and between sites, reflecting both changes in sulfate availability as overlying water salinity changed and sediment metabolism. Patterns of sediment redox potential followed those of sulfide. Porewater profiles of inorganic N and P reflected strong seasonal patterns in remineralization, accumulation, and release. Highest porewater NH4+ values were found in upper and mid estuarine sediments, occasionally exceeding 1 mM N. Porewater nitrate was frequently absent, except in the sandy marine sediments where concentrations of 8 muM were often observed. Annual average respiration was lowest at the marine site (13 mmol O2 m-2 d-1 and 21 mmol TCO2 m-2 d-1) and highest in the mid estuary (130 mmol O2 m-2 d-1 and 170 mmol TCO2 m-2 d-1) where clam densities were also high. N2O and CH4 fluxes were low at all stations throughout the year. Over the course of a year, sediments varied from being sources to sinks of dissolved organic C and N, with the overall spatial pattern related closely to sediment organic content. There was little correlation between PO43- flux and metabolism, which we attribute to geochemical processes. At the two sites having the lowest salinities, PO43- flux was directed into the sediments. On average, between 22% and 32% of total system metabolism was attributable to the benthos. The mid estuary site was an exception as benthic metabolism accounted for 95% of the total, which is attributable to high densities of filter-feeding clams. Benthic remineralization supplied from less than 1% to over 190% of the N requirements and 0% to 21% of the P requirements of primary producers in this system. Estimates of denitrification calculated from stoichiometry of C and N fluxes ranged from 0% for the upper and mid estuary site to 35% for the freshwater site to 100% of sediment organic N remineralization at the marine site. We hypothesize that low values in the upper and mid estuary are attributable to enhanced NH4+ fluxes during summer due to desorption of exchangeable ammonium from rising porewater salinity. NH4+ desorption during summer may be a mechanism that maintains high rates of pelagic primary production at a time of low inorganic N inputs from the watershed.
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http://www.ukmarinesac.org.uk/commu...-mud/ism5_5.htm

http://www.aoml.noaa.gov/ocd/sferpm...mant_Final.html
http://www.aoml.noaa.gov/ocd/sferpm...on/carlson.html

http://www.botany.hawaii.edu/Bot482...0Mar Biol.pdf

http://www.mpi-bremen.de/flux/


mike