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Reefkeeping made easy- what was not explained.

899515 Views 1783 Replies 195 Participants Last post by  hackshobby
here are a few threads that were started in another forum about what is going on in our system. hopefully some of you all will read the information here and start to get a handle on what makes our systems work or not work. I know this may require some reading and those on the internet are allergic to reading threads that are not theirs, but give this thread a go. I am hoping that it will answer most of the questions you may have about reefkeeping. these first three posts may be a bit disjointed. as they came from the other thread. I will try and edit them so that they flow a bit better and lead into each other better.

the biggest things we will be discussing in this thread are the biological process that are going on in our systems. these biological process are what most of the false information that is out there is about. this includes reef forums and LFS. The two main elemental processes we will be discussing are the Nitrogen and Phosphate cycles that are occurring in our systems. these two elements lead to the greatest confusion about what is going on in our little slices of ocean.

There will be a lot of information in this thread. I will be linking to other threads with even more reading and papers on the subject at hand for even further reading. This hobby is easy if you understand what is going on, if you do not care to understand what is going on and listen to a lot of false information out there, then this hobby can be very frustrating and lots of wasted money.
I would anybody to ask questions if they need clarifications. I will try and keep things as short as possible to keep the reading down to a minimum, but some of this stuff is fairly long winded in general.



A sort of Table of Contents for the thread. please feel free to PM any subjects or pages i should add to the contents.

Introduction: Page 1
Nitrogen cycle: Pages 1-2, 22
Phosphates: Page 3, 31
Sources of Phosphates: Page 3
Phosphate Cycle Graphics: Page 35
Early Tank Processes: Page 30
Problems with Sand: Page 4, 19
Sandbed Cleaning:page 7
DSB's: Page 9
BB Alternatives: Page 25
About LR: Page 8
LR Purging: Page 19, 26
Cured LR: Page 23
Tank Flow: Page 7
Light: Pages 13-15
Kalkwasser: Page 12, 17
Feeding: Pages 17-19
Zoax: Pages 15-17
Carbon Dosing: Pages 24-25
Tank Self Feeding: Page 27
Conservation of Matter: Page 28
Beer!: Pages 6-7
Bad Experts: Page 19
Definitions according to Spanky: Page 21
My Reference Links: Page 37
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Lets start with the nitrogen cycle. we all know that it starts with ammonia, then nitrite, then nitrate, then it is off gassed as N. If all is going fine then there should not be any nitrate in the system. the problem is that nobody goes through what is necessary to remove each of these phases and where the bacteria need to live in order for them to perform their jobs. The process of ammonia to nitrite and nitrite to nitrate take place in oxygenated areas. Any area that has oxygen is going to be able to process up to nitrate. this includes wet/dry filters, sand filters, canister filters, filter socks and sponges, overflows the sides of the tank, anything inside the tank really. the problem comes when we want to convert nitrates to N gas. this require an anoxic (low oxygen) area. the best place for this is the LR. Sand can accomplish this, but the sand bed does not have as much surface are as the LR does for handling the entire nitrogen cycle. the sand bed is more of a 2 dimensional surface while the LR can process over its entire surface. if you are showing nitrates in your system then you have an imbalance between the oxygen areas and the anoxic areas. Once the nitrates are free within the water column they are difficult to remove. this is why people rely on nitrate reducers and algae. All of the bacteria that handle the entire process reside very close to each other. with one layer feeding the other. this is why when the nitrates are free they can not get to the anoxic layers because they are already feeding on the nitrates that the layer right next to them are supplying them. Hard surfaces do not have the depth necessary to create the anoxic layers. This is why those open cell sponges and socks, and wet/dry media are nitrate factories. They just can not provide the anoxic environment to process the nitrates to N gas. OK, now comes the part about the public aquariums. sand filters are extremely efficient at removing ammonia and nitrite because they are high flow oxygen rich areas. we have found out that while ammonia and nitrite are fairly toxic to most marine life, nitrates are not. Nitrates are actually fairly benign. They were given the bad rap because people could test for nitrates, but not test for phosphates easily. They tend to go hand in hand. so people saw their nitrates going up and their tanks crashing and though the nitrates for killing their systems. Not the case, though some inverts are more sensitive to nitrates than vertebrates, once again it was the phosphates. Those extremely large systems are fish only for a reason. they can employ those large sand filters and remove the toxic ammonia and nitrite leaving the nitrates, which can be removed by water changes. though i am not sure how often that occurs on those Uber systems.

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Alright here is some reading material to browse through. These are my reference threads for 95% of all of the information i have talked about. Within several of these threads are links to scientific articles for those that are interested delving deeper into the subject. Feel free to book mark these for future reference. I should probably create a thread and sticky it.

I had forgotten about this thread. fantastic read. please, please just read the first page on this one.

about nitrification.

discussion about LR.

OK. those are the most relevant for the current talk about nitrification. I have a whole lot more that i will post when we get more involved in talking about phosphates and what they really do in out systems.

Is everyone following OK? Do I need to expand on anything? Any info from the fuge people that anybody wants to add?

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We will get to phosphates shortly. It is good to get the nitrate cycle out in the open and understood instead of just knowing that when your test kit says 0 it is go nuts time. :-(

We see plenty of threads out there about people trying to get rid of nitrates, yet nobody seems to have any real answers. Knowing the environment for the different bacteria goes a long way in figuring out exactly how much filtration you have in the system and if it is balance. You will find that you really do not need as much LR as you think. LR is extremely efficient of cycling N through all of its different compounds.

here is a pdf of the basic info on the big display at the Georgia Aquarium. seems awfully simple huh? ;-) of course i think this is overly simplified. skimmers are not replicating anything in nature. i am sure there is other equipment though finding a better description online is proving annoying.

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Do we have any questions on the nitrate cycle? Does everyone promise not to post questions on why they have nitrates, and how they got there?

but wait nitrates cant go away due to N gas being too much oxygen in our tanks. but wait theres more. nitrates feed algae like phosphates
could you elaborate more please on the N gas?

nitrates and phosphates are both great fertilizers for plant (oh sorry algae) growth, an abundance of either will lead to algae problems

but wait theres more theres two types of phos in our tank one is soluble which is testable the other non-soluble which is not tested for and that one is the downfall of most tanks as it cant bond with the mag and alk
we will get into more of this. i have a lot of reading i need to do. its been three years since i had to access this stuff. :D

the N2 gas that has been released will just go off into the water column then out into the atmosphere to reach standard atmospheric concentrations. the agitation of the water is not as much of a problem as it is with O2 in the water column. N2 is just there. it just happens to be what most of the atmosphere is, but it is not a limiting factor for the holding back the amount of O2 and CO2 in the system. the skimmer is a fantastic air water interface. it allows the the water and the atmosphere to reach equilibrium. the only time there could be a problem with gas exchange would be, like you have suggested, there is a barrier on the waters surface like a film. this can cause an imbalance of dissolved gasses. though when this occurs you will see an decrease in pH from the increase in CO2 in the system. at which point the release of the N2 into the atmosphere is the least of your worries and correcting the CO2 problem with correct the N2 as well.

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i am not sure that is the case. i do not think that the depth of the anoxic layer changes within the sand bed or the LR. i do not think that the percentage of O2 in the system can change by enough to cause much fluctuation in the anoxic depth. i will see if i can find any info on that though, it is a good point. as long as there is very little flow in an area it does not take much to make it go anoxic. hence the problem if the power ever goes out in our systems. :( so those little nooks and crannies in the LR can easily create anoxic layers below the areas processing the ammonia and nitrite.

you can even see the N2 bubbles forming on the the LR and releasing into the water column.

not exactly what i was looking for, but could be interesting.

i have a feeling to really find the answer about the anoxic depth changing per O2 concentrations of the solution it would require better access to journals then i have, though i have yet to really pull strings here at Duke in the Biology department.

it could, i am not saying it does not. i just was not able to find any papers to help in determining this fact for sure. either way the difference is going to be very small unless you are getting serious movement in the sand creating dunes in the system. this would absolutely make a difference in the anoxic layer by several inches. though with little substrate movement i would think the anoxic layer would not change by much more than a few mm.

Vince is right on. the LR itself is a much more efficient means of processing the nitrates instead of a sand bed.

Ntvper could have a point in trying to find the most efficient depth for a sand bed in the system.

Scott- you are correct. the deeper the sand bed does not allow more nitrates to be processed. that is what people think, but in reality the nitrates can not get down to those layers because the nitrates just can not get there. the nitrates that are processed are coming from the layers above and any additional nitrates that could get through are already being processed. if more were to get there, that would mean that O2 rich water was getting to that area, which would hinder the conversion of the nitrates to N2

Nitrogen Gas=N2

a decent little blurb i came across.

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ok, onto everyones favorite topic, even though 90% of aquarists do not realize it: phosphates.

what are they and why do we care about them? why does nobody seem to know about them. what is it with LFS/web boards and the complete lack of knowledge about this one element which causes so much grief to all aquarists?

things may get confusing in here. please use quotes when necessary to keep everyone on track of where you are coming from. feel free to bounce back to the nitrogen cycle when necessary if more clarification is needed.

there were some monster names in the hobby that called this place home. i would hang on for dear life in The Think Tank forum. i would have the time to go into the General forum and explain the topics so that everyone else could understand. i would do searches on my own to help me keep up and i would keep the links to those that i could understand and i would think others would also.

work got a hold of me today. i have not had the chance to study up on all of my reference threads to really get into the Phosphates yet, i will do more reading when i get home to make sure i keep it all straight once you all start really asking the questions. TRT will be posting a new sticky at the top of the forum which will contain our favorite reference links. where i have gotten 99% of my information. i am not really that smart. i had just been in reefing so long that none of it was making any sense till around 2003 when the whole sand thing started blowing up.

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i saw that one, but was kinda hoping for a little easier one to start with. i am brushing up on my phosphate chemistry again. i am not good at this part of the process. i want to lump the phosphates together, but i am afraid it will confuse everyone, but then trying to keep the two separate is going to be tough for me. i may just start going and hopefully the more chemistry minded will quickly correct me when i get the two mixed up. it should not happen that often, but phosphates are confusing enough as it is.

anywho. phosphates are needed for all life. they come in two forms orthophosphates and inorganic phosphates. one of the reasons why it has taken so long for us to put the blame on phosphates for tank crashes and other problems is that phosphates are hard to test for. for a very long time phosphate tests were very expensive because nobody know to even test for them. then there was the problem that the test kits at the time would only test for orthophosphates. the problem here is that the cyano/algae/bacteria all want this and will uptake it immediately. it is hard to get any reading when testing for orthophosphates in a working system. you could have a decent sized algae farm in your reef and yet your phosphate test kit would read 0. when you are actually getting a reading means that all of the bacteria in your system has bound all of the orthophosphates it can and now there is some free in the water column.

orthophosphates (i will use phosphates for this) are what algae and the bacteria are looking for for energy to live. it is limiting in the system. if you have very little, you will have very little available for the algae/cyano. the higher critters will be getting the phosphates they need through the food you give them. we get our phosphates through our mouths. algae and the bacteria get it through their surfaces. if you can virtually eliminate it from the water column then you virtually eliminate the algae/cyano.

make sense so far?

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ok, just one more, though more audience participation time.

we know that all food contains phosphates. they can actually contain both types of phosphates. not overly important, though i thought it should be mentioned. what other sources can you think of for phosphates?

hint: start naming everything you have ever thought of to put in your tank.

ok. lets speed this up a bit. sorry, i have been a bit out of practice on this after 2 years off.

ok, so we know phosphates are important for life. it would make sense that we would know the best places to find it for our needs. does anybody want to guess where we get phosphates from in bulk?

use this to get you started.

yep those are all sources of phosphates.

sorry for all of the Wikipedia cuts, but i am at work and do not have huge amounts of time to find better articles. :-(

lets start with Live Rock. ok from the link i posted we know that phosphates are mined from limestone, or any large deposits of calcium carbonate. calcium carbonate is a great phosphate binder:

"Calcium carbonate is widely used medicinally as an inexpensive dietary calcium supplement or gastric antacid.[7] It may be used as a phosphate binder for the treatment of hyperphosphatemia (primarily in patients with chronic renal failure). It is also used in the pharmaceutical industry as an inert filler for tablets and other pharmaceuticals."

LR, aragonite sand, and coral skeletons are all composed of calcium carbonate. being that all of these started out as corals at some point.

"Coral calcium is composed primarily of calcium carbonate (CaCO3), with small amounts of magnesium and other trace minerals. Calcium carbonate from coral is similar to calcium carbonate from other sources, with varying amounts of trace minerals."

so it does not take a large leap of logic to come to the conclusion that all of these must have various levels of phosphates within them. whether it is an actively growing coral or some sand laying at the bottom of the tank or the crushed coral media in a calcium reactor. there is going to be phosphates.

ok? any questions.

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Scott in that section Randy was talking about what happens when kalk is used in the system and how it interacts with the phosphates. i am a firm believer in using kalk (limewater) for all of your top off water if you are running a reef tank. not necessarily for what Randy was talking about. what Randy was saying is that the phosphates can bind with the kalk and either precipitate out and bind with the calcium carbonate structures and become a sink for the phosphates or become locked up in the water column where they can be skimmed out by the skimmer. the way most people have their top offs setup up, i believe the second scenario is more common.

there were a few bits i need to point out in that article in that GFO thread.

i would have liked for him to expand more on the absorption of phosphates by calcium carbonate since this is what all of our sand in LR is made of. though if he had it would have raised red flags with the sand lovers on RC. which is not a good thing.

anyway, there it is we know calcium carbonate is a good phosphate binder. it is not in its optimum pH of 8.4 but it is pretty close at 8.1 which very common in our systems.

we good? phosphates are necessary. they are limiting for the growth of algae/cyano. they are found in calcium carbonate, which is what our sand, LR, and calcium reactor media are made of.

how do we get rid of it?

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so, how am i doing? do i get an A!

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