Natural Filtration

[Subsea]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4286716/

 

I have been encouraged to keep some of my comments about biological filtration in one place.  It allows for a much better platform for discussion without infringing on someone else’s post.  

 

While the above link deals with the complex overall picture of one part of what happens on a natural reef.  Through complex food webs involving bacteria and algae, the reef feeds itself through “carbon fixation” in which dissolved carbon dioxide converts to carbonate & bicarbonate that when coupled with photosynthesis produces glucose, which is a carbon source.

 

This link shows how carbon is transferred in a system between the primary and the secondary producers.  I just found this link and will study on it more.  In the “significance for a reef tank” section, at the conclusion, the author states,  “DOM from coral is rich in proteins & lipids and DOM from algae is rich in carbohydrates.  Algae DOM is essentially junk food.”  I found that very interesting.  It agrees with a thread on RC with Steve Tyree and my friend Timfish concerning cryptic sponges.  Previously, my answer to algae DOC is to use GAC and prune macro (seaweed).  Well, four months ago, I turned out the lights on my 25 year old 30G EcoSystem mud/macro refugium and seeded with cryptic sponges.  It was already mature with pods, micro stars, feathers and worms.

 

http://www.advancedaquarist.com/2017/9/aafeature

 

With this article, Danna Riddle shows that the stony coral, Porites lobata increases photosynthesis of carbon with ammonia over nitrate required by other corals..

 

http://www.advancedaquarist.com/2017/2/aafeature

 

The link below  is the starting point of my discussion.  It defines how carbon dioxide is utilized by coral building zooanthelia.  I don’t agree with adding organic carbon to a reef tank and indirectly this article supports my conclusion, that organic carbon dosing in a reef tank fuels bacteria, which consume/transfer 60% of the energy in a reef tank through the “microbial loop”.  After reading these articles, I consider using calcium reactors in all reef and macro tanks that I own and running UV sterilizer 24/7.  I don’t use the sterilizer on my 25 year old tank.  I do use sterilizer on everything else.

 

 

http://www.advancedaquarist.com/2016/9/aafeature

 

[Subsea]

Referring to “growing  coral quicker” article by Dana Riddle, his second paragraph caught my attention.

 

Liebig’s Law states, “not by the concentration of the most abundant element but by the supply of the least abundant”.  Dana focuses on alkalinity as the building block for coral.  Alkalinity derived from inorganic carbon dioxide.  I liked this best, “Photosynthesis is the link between the inorganic and the organic worlds”.  

 

With my use of aroggonite sandbeds, I have supplied soft corals with all the alkalinity required.  When hard corals build their limestone shell, they consume huge amounts of alkalinity.  Because of their increased demands on system, I always stayed away from them.  However, with the use of a calcium reactor using carbon dioxide to dissolve aroggonite is a perfect two punch system.  You are getting the minerals from aroggonite to support alkalinity and you are also supercharging your system carbon source with glucose from photosynthesis.

[RayWhisperer]

All fine and dandy. But do you plan on doing anything about the inherently lowerd ph associated with a calcium reactor? Easily fixed with a simple kalk drip. However, since we're on calcium reactors and doing extras on too of that.... Do you plan on keeping track of said reactor daily? As every one I've run required at least weekly tweaking/cleaning, in order to maintain a consistent effluent rate. As well as daily monitoring of cal and alk to try and avoid any problems.

 

ive always had best results from a reactor. But, I'm getting lazy in my older years. One more thing isn't what I want.

[Subsea]

While pH may be lower with use of calcium reactor, I see no problem with that.  If proper gas exchange is maintained in reef tank flow design, the Dynamic Equilibrium gas partial pressure law will self correct.  It is normal for pH to drop during lights out.  Perhapes reef keeping should take its cue from “Mother Nature” and let pH fluctuate naturally.  It fluctuates naturally on the wild reef as much as .20 pH units.  I say relax about pH.

 

With respect to operation of calcium reactor, I do not monitor both calcium and alkalinity.  Each changes dramatically during the cycle of the day.  I pick one of the two parameters and that is what I test for.  Also, because I never had to deal with the high demand for alkalinity by SPS, the natural reduction of pH during lights out causes aroggonite sandbeds to start dissolving at a pH of 8.05.  That has supplied alkalinity demand for my mixed garden tanks.  In most cases, I don’t use calcium reactors for my tanks with aroggonite  sandbeds.  Aroggonite supplies alkalinity and CO2 supplies carbon.  We get CO2 through good gas exchange in our reef tank flow design.  It is a two way street.  If calcium reactor puts too much co2 into water the gas exchange reduces co2 concentration.  If tank needs co2, then gas exchange adds it according to the partial pressure law.

 

 

 

[RayWhisperer]

Well, I can't speak for a low demand situation. I always ran reactors on sps systems. With those, it would stay severly depressed throughout the day, regardless of how much surface agitation was used. 

 

Something else I'd suggest. Throw in about 1/3 the volume of the reactor of dolomite. Aragonite is fine for calcium, but dolomite gets you the magnesium.

[Subsea]

Yes to dolomite/aroggonite and magnesium/calcium.

 

I have not measured alkalinity, calcium or ph is > 30 years.  I can’t address the severely depressed pH comment.  

 

What pH is considered severely depressed?  

 

When I ran a calcium reactor, it was on a 1500G system with several growout troughs that were 4’ by 8’ by 6” deep.  Perhapes the large surface area of the troughs that were outside assisted with gas exchange. Also, if your home has good insulation, it is probable that you already had elevated CO2 in the air that your tank is trying to equalize partial pressure with.  That would mean that your tank would have a higher level of carbon dioxide with a depressed pH.  Just a thought.

 

 

[RayWhisperer]

Lol. Nah. Those days I kept the window open most of the year. 400 watt halides in a small room. 

 

As for severely depressed. It would hover around 7.2 to 7.4. I had the effluent dripping right next to the skimmer outlet, and dripped kalk all day just to keep the ph above 8.

[Tanksy]

Interesting discussion. Thanks for the links Subsea.
May I ask, what would happen if I use aragonite (like Caribsea Bahamas Oolite) as a substrate? Wouldn't it be dissolved when the pH dropped during the night and thus adding calcium to my system? If the answer is yes, then why would I need a calcium reactor?

[Subsea]

3 hours ago, RookieRock said:

Interesting discussion. Thanks for the links Subsea.
May I ask, what would happen if I use aragonite (like Caribsea Bahamas Oolite) as a substrate? Wouldn't it be dissolved when the pH dropped during the night and thus adding calcium to my system? If the answer is yes, then why would I need a calcium reactor?

During lights out, the reduced pH would, in fact, begin to dissolve aroggonite. Notice, “begin to dissolve”.  The degree of buffer added thru sand bed dissolving, slowly over time, depends on the alkalinity uptake of your tank inhabitants..  SPS demand the most of alkalinity because of their limestone reef building property.  

 

So, it’s your tank.  You decide.  Sand bed dissolving naturally requires no controls and it supplies alkalinity and trace minerals.  Calcium reactor supplies alkalinity, trace minerals and carbon dosing.  I used manual controls on the calcium reactor and measured alkalinity once a week at the same time of day. 

[Subsea]

5 hours ago, RayWhisperer said:

Lol. Nah. Those days I kept the window open most of the year. 400 watt halides in a small room. 

 

As for severely depressed. It would hover around 7.2 to 7.4. I had the effluent dripping right next to the skimmer outlet, and dripped kalk all day just to keep the ph above 8.

Mighty low pH.  Day time?

 

You must grow a lot of SPS to push your calcium reactor that hard.

[Tanksy]

40 minutes ago, Subsea said:

During lights out, the reduced pH would, in fact, begin to dissolve aroggonite. Notice, “begin to dissolve”.  The degree of buffer added thru sand bed dissolving, slowly over time, depends on the alkalinity uptake of your tank inhabitants..  SPS demand the most of alkalinity because of their limestone reef building property.  

 

So, it’s your tank.  You decide.  Sand bed dissolving naturally requires no controls and it supplies alkalinity and trace minerals.  Calcium reactor supplies alkalinity, trace minerals and carbon dosing.  I used manual controls on the calcium reactor and measured alkalinity once a week at the same time of day. 

Thanks for replying Subsea.

Since this discussion is about "natural filtration", I was wondering what would you consider to be "natural filtration" in a tank with lps and soft corals, that are not too demanding in general?

[Subsea]

With those corals, I would use a 1” sandbed of aroggonite.  Add dolomite for magnesium.  If you don’t have rabbits and Tangs, use ornamental macros in display tank.  That is it.  Skimmerless and sumpless.  I also use small amounts of GAC 24/7 changed out every 2 weeks.

 

In my 120G new build at 8 weeks old, I have a 40G cryptic sponge refugium.  My 2” sandbed sits on top of a undergravel filter.  I pump into the void of this Plenum to flow up thru the sand bed.  This prevents gravity from pushing detritus deep into sanded as well as preventing anaerobic chemistry.  On this system, I use a 40W UV sterilizer 24/7.

[RayWhisperer]

9 hours ago, Subsea said:

Mighty low pH.  Day time?

 

You must grow a lot of SPS to push your calcium reactor that hard.

Yes, daytime. 

As for growth. When it was going, it grew loads. However, those were also the days of keeping the alk pinned at 12. There were several times I’d come home from work, or wake up in the morning to alkalinity burn. The reactor would stick on and I’d end up with an alk of 15. So, in the end, I don’t think I grew any more coral than any other system I’ve run. It just grew fast in between burns.

[Subsea]

10 hours ago, RookieRock said:

Thanks for replying Subsea.

Since this discussion is about "natural filtration", I was wondering what would you consider to be "natural filtration" in a tank with lps and soft corals, that are not too demanding in general?

https://www.advancedaquarist.com/2011/3/aafeature

 

Let’s explore how reef tanks process nutrients.  Ken Feldermen has written several peer reviewed scientific papers on carbon dosing in reef tanks.  

 

Using DOC (dissolved organic carbon) as the marker, results showed:

protein skimming removed 35% of DOC

GAC removed 60% of DOC

In a mature reef tank, the biofilter removed 75% of DOC.

[Tanksy]

18 hours ago, Subsea said:

With those corals, I would use a 1” sandbed of aroggonite.  Add dolomite for magnesium.  If you don’t have rabbits and Tangs, use ornamental macros in display tank.  That is it.  Skimmerless and sumpless.  I also use small amounts of GAC 24/7 changed out every 2 weeks.

 

In my 120G new build at 8 weeks old, I have a 40G cryptic sponge refugium.  My 2” sandbed sits on top of a undergravel filter.  I pump into the void of this Plenum to flow up thru the sand bed.  This prevents gravity from pushing detritus deep into sanded as well as preventing anaerobic chemistry.  On this system, I use a 40W UV sterilizer 24/7.

Wow! That's a beautiful DT.

 

Aragonite for calcium and dolomite for magnesium, got it

I understand the concept of an undergravel filter. I think that a shallow sandbed would stay clean enough just by adding a fair amount of sand shifting creatures, right?

 

[Subsea]

37 minutes ago, RookieRock said:

 

39 minutes ago, RookieRock said:

Wow! That's a beautiful DT.

 

Aragonite for calcium and dolomite for magnesium, got it

I understand the concept of an undergravel filter. I think that a shallow sandbed would stay clean enough just by adding a fair amount of sand shifting creatures, right?

 

 

In most of my lagoon growout tanks, I use < 2” of Special Reef Grade aroggonite on bottom.  Gravel vac and janitors works fine.

[Subsea]

On 2/19/2018 at 3:19 PM, RayWhisperer said:

All fine and dandy. But do you plan on doing anything about the inherently lowerd ph associated with a calcium reactor? Easily fixed with a simple kalk drip. However, since we're on calcium reactors and doing extras on too of that.... Do you plan on keeping track of said reactor daily? As every one I've run required at least weekly tweaking/cleaning, in order to maintain a consistent effluent rate. As well as daily monitoring of cal and alk to try and avoid any problems.

 

ive always had best results from a reactor. But, I'm getting lazy in my older years. One more thing isn't what I want.

I continue to think on this low pH comment.  At the time that I used a calcium reactor, the system size was 1500G,  The needle valve for metering CO2 was a weak link.  I kept my gas bubble rate higher to allow valve to work steady state without plugging up.  I had built my own reactor where gas and raw water entered at the bottom and effluent left at the top.   While I would have to tweek effluent flow monthly, it was not a problem for me.  During those days, my pH would fluctuate from 8.15 - 7.85.  With soft corals, LPS & macro algae  I was not concerned about pushing alkalinity.  

 

 

[Subsea]

Why do I use macro algae?

 

I like the way it looks in my garden.  I use texture & color provided by macro.  Easy to prune and remove for nutrient export.  

 

Fish naturally graze on biofilms on macro surface.  These biofilms are complex, interactive “quorum sensing signaling” and very nutritious.

 

https://www.intechopen.com/books/algae-organisms-for-imminent-biotechnology/biofilms-an-extra-coat-on-macroalgae

 

55G macro growout tank.

[Subsea]

The two most important  reasons for me using “natural systems”,

 

It is easy and it is nutritious to produce live food in the tank. With “nutrient recycling” using complex “nutrient pathways” differrent live food webs are established.  This establishes food size.  Differrent corals have differrent mouth sizes as other “filter feeders” do.

 

THIS TANK IS 25 years mature using natural filtration.

 

 

https://www.advancedaquarist.com/2015/2/aafeature

This is the link that I meant to post.  It is a Dana Riddle article on coral nutrition.  It is Part 2.

 

 

 

[Subsea]

Musings from the Lazy Boy

 

One of the beautiful things about natural systems:  stuff grows abundantly.  For many new reef keepers, some of that abundance, like algae, is intimidating.  The part of this hobby I like the most is to find an appropriate consumer of algae.  First and most importantly are the micro inverts like copepods that are both detrivores and herbivores.  Contrary to many reefkeeping “sacred cows”, I feed heavy and watch the micro invert populations grow.  Phytoplanktonic copepods are a primary consumers of carbon to feed the rest of the ocean.  Why not your reef tank?  

 

Recent observations in 10G species tank:  baby bristle worms eating new growth on Ulva.  This tank lost its Peppermint Shrimp as its apex predator.  That role is now filled by bristle worm and carnivore snail.  For herbivores, this tank has Cerith Snaile as well as amphipods & copepods.

[ajmckay]

Nice post subsea - definitely an area where I can stand to learn more.  To that end I appreciate the links - will take me some time to go through them.

 

 

[Subsea]

4 hours ago, ajmckay said:

Nice post subsea - definitely an area where I can stand to learn more.  To that end I appreciate the links - will take me some time to go through them.

 

 

Thank you for the kind words.  This stuff fascinates me.  Nature is complex and efficient.  I find beauty in how things work in harmony.   The more I learn, the more beautiful it gets. 

[Tamberav]

I love micro inverts, I find all those little guys fascinating and sort of adds a realism to the reef instead of a sterile looking environment. 

 

While my 22g is run off skimmers/gfo, ect. I do plan on setting up my 25g to be a heavy fed system, I had a macro/softy/lps tank previously I fed the hell out of and really enjoyed that approach and would like to do it again. All the corals we have to choose from and I find I like macroalgae more. 

 

[Subsea]

“I like macro more”.

 

As I have raised Red Ogo, Gracilaria Parvispora, and eaten it as a salad or as a garnish in my cheviche recipe, I must say I like macro a lot. Grape Caulerpa is pretty good with lime juice and soy sauce as well.

 

I enjoy my high nutrient macro lagoons.  I just did add fish to my 120G new build after 90 days of set up.  Amphipods, copepods, micro starfish & bristle worms came in on GOM live rock.  I also seeded three differrent cultivars of copepods from AlgaeBarn.  Pods & reproducing Cerith snails are everywhere.  I hope green mandarin enjoys his new home.

[Subsea]

On 4/2/2018 at 11:58 AM, Subsea said:

Musings from the Lazy Boy

 

One of the beautiful things about natural systems:  stuff grows abundantly.  For many new reef keepers, some of that abundance, like algae, is intimidating.  The part of this hobby I like the most is to find an appropriate consumer of algae.  First and most importantly are the micro inverts like copepods that are both detrivores and herbivores.  Contrary to many reefkeeping “sacred cows”, I feed heavy and watch the micro invert populations grow.  Phytoplanktonic copepods are a primary consumers of carbon to feed the rest of the ocean.  Why not your reef tank?  

 

Recent observations in 10G species tank:  baby bristle worms eating new growth on Ulva.  This tank lost its Peppermint Shrimp as its apex predator.  That role is now filled by bristle worm and carnivore snail.  For herbivores, this tank has Cerith Snaile as well as amphipods & copepods.

Predator/prey relationship in marine aquarium have always fascinated me.  In my 25  year old 75G Jaubert Plenum, a Melanarious Wrasse wrecked my sandbed Janitor crew.  It took 18 moths for me to realize  the source of my problem.  I added wrasse to control Red Planaria and he did his job at the expense of my sandbed Janitor diversity.  During the last six months, I have vacuumed sandbed down from 6” to <  2”.  I also turned out the lights on 30G EcoSystem mud/macro refugium.  Cryptic refugium was seeded with cryptic sponges.  Large pods and micro stars are everywhere as or numerous tube worms and feathers.

This morning while drinking my first coffee, as I feed my 10G tank some flake food, I saw the normal quick response to food in tank with carnivore snails and bristle worms popping out of sandbed along with large amphipods.  I am not sure who the apex predator is anymore.  I noted a very large amphipods eating his flake with bristle worms attempting to encroach on his food.  I did not exactly see what the amphipod did, but the reaction of the bristle worm was instantaneous.  It withdrew.  I could not understand this behavior.  Less than a week earlier, I witnessed bristle worms feeding on large Peppermint Shrimp before they were completely dead.  Yet, this morning, I witnessed an amphipod, supposedly a herbivore,  “back down” a predator carnivore.  It tells me that many of the creatures in our marine tanks are opportunistic.  

 

Nature is very efficient.  Most always there is a secondary nutrient pathway.  Take corals for instance.  As a rule, corals feed in two ways.  One pathway comes from symbiotic relationship of coral zooanthellia (algae) to coral polyps in which inert nutrients like nitrogen and phosphorus combine with alkalinity coupled with photosynthesis produces glucose, which is a carbon organic biomass.  This process is the primary “carbon pump” to planet earth.   Zooplankton capture is the second way in which corals feed.  It is to this purpose that heavy feeding and diversity at all levels of the food chain provides nutrient pathways for complex food webs to feed nutrious live food produced in tank.