feeding and nutrient removal: BY ME

[reefkprz]

Food availability and Nurient removal in marine tanks, and its lack thereof.
By:Erick Chambers
.........Feeding and removing the byproducts in marine aquaria is one of the biggest challenges aquarists face in maintaining healthy fish and corals. In my opinion, especially corals. As the currents in the ocean tend to bring in plenty of food and carry away all/most of the waste leaving no un-utilizable waste products behind, often suspending the waste long enough to be consumed by another form of life. I believe oxygen availability and retention also plays a key role in this. oxygen in the natural reef systems is often superaturated and freely abundant, nearly impossible to mimick in our aquariums.
....... Often you hear advice like feed your tank every other day, and such. In part it is sound advice for those beggining the hobby but in whole often not even close to what your fishes and especially corals will need in the long run. In the ocean fishes and corals spend all day or night feeding and photosynthesizing as needed. Some species of corals are so dependant of foods that they are nearly impossible for your average aquarist to house for long periods before they die. Non photo synthetic gorgonians being among them. Generally corals like these tend to "do fine" for 6-8 months before wasting away to the owners great dismay. Often the death of such corals are mis-attributed to some minor fluctuation in parameters and the aquarist purchases another similar creature only to expirience the same thing 6-8 months later. By then the aquarist decides against further keeping because of the lack of success or has learned through research the difficulties in keeping such creatures, hopefully the latter. But 1 or 2 corals have died to provide the example. a dismal count in my opinion.
.........In my expirience feeding should be more dictated by individual species needs as well as the ability to export the excess/byproducts. The challenge comes in learning how much nutrient influx our equipment, natural filtration, microfauna, corals fish and waterchanges can cope with. In my expirience there is no such this as over feeding just under exportation of waste, waste falling into the categories of, coral waste, fish waste, uneaten food, by products of waste (ammonia nitrite, nitrate), and so on.

 

[reefkprz]

......... With the right equipment and maintinence as well as supportive flora and fauna it is very possible to "feed" (we shall discuss what I mean by feed a tank in a few minutes) a tank 6 or 7 times a day, and not be "overfeeding". I have been doing just that for a long time and have found that having a high population of corals, detritivors, sand shifters (not sifters) ample mechanical export, as diverse a micro fauna base as can be introduced, as well as high biological capability and the best oxygen exchange that you can arrange, coupled with ample water changes makes a closed system well capable of handeling such a high amount of "foods".
...........Now just as a point of clarification I dont mean feeding one type of flake fish food 6 or 7 times a day... I mean feeding your entire tank not just fish. There are countless corals and other forms of life that rely in part or in whole on nutrition derived from capturing "food" be it phytoplankton, zooplankton, detritus, bacteria, coral fish or oyster eggs, flocculent, nitrogenous compounds or what have you.
.........In general the amount of available food and waste removal in the ocean is gargantuan by comparison to even our largest tanks. By largest I'm not implying 75 or 90 gallon tanks I'm talking commercial aquariums at tens of thousands of gallons even they pale by comparison to the sheer volume of the ocean.
..........There are many types of foods available to us in the hobby some are fairly good and some are just clever marketing and bulk fillers. Proper research into ingredients, preservatives, shelf life, and estimated nutritional value should be under taken with care. Often foodstuff labled as a miracle food in a bottle is in truth pollution waiting to happen. More often than not the consumer winds up paying a signifigant amount of money for water with a little suspended plankton in it that may or may not be in the utilizable size range for the creatures it is intended for. Same things with flake or pellet foods often you end up buying a high percentage of fillers in your food like "cereal" or "wheat flour" you show me where the wheat mill is in the ocean and I'll feed it to my tank. As more and more research shows terrestrial foods should be avoided for aquatic life, especially meats, often terrestrial meats are just too fatty and can severly affect the long term health of your fishes.
..........In the long run I have had the greatest success with foods of my own making not having bulk fillers or preservatives. The "shelf life" of homemade foods is far shorter for not having preservatives but the nutritional impact is far higher for not having wasted "space" therefore allowing you to feed smaller amounts to achieve the same level of nutriton. I have also found making your own foods is also far cheaper in the long run. The ability to tailor the ingredients to the exact needs of your own aquarium can eliminate the need for storage of 8 different types of foods to feed various fishes and corals.

 

[reefkprz]

....... Having proper equipment can compensate to a point when it comes to export. having a protien skimmer that far exceeds the actual size of the tank is a good start but you also have to compensate for the increased calcium consumption for the larger skimmer as skimmers are exceedingly efficient at removing calcium amongst other trace elements. obviously I cannot list all the ways to possibly remove waste from a tank in an article this short it could take up an entire extremely large book listing all the possible equipment and filters and techniques we have at our disposal as well as trying to list their proper useage and benifits and draw backs. since I touched on protien skimmers briefly let me digress into some of the pros and cons of this particular type of equipment.
.........Foam fractionation devices or protien skimmers as they have been dubbed, are capable of many things. Their primary intention is to remove protiens from our water by creating micro bubbles that protiens adhere to and ride to the top of the water column generally to be collected in a cup or other receptical. Unfortunatly that is not all a skimmer removes, a lot of the planktons that our corals feed on are small enough to become trapped in the same manner, as well as several of our desired elements such as calcium the list of elements a protien skimmer is capable of removing in minute and signifigant amounts is quite long. Fortunatly the high air to water contact time can increase oxygen levels signifigantly in smaller aquaria and help out in larger. As you can see there are pros and cons to every form of nutrient removal.
..........This is where ample water changes can also assist, not only do water changes remove waste they also replace trace elements that are consumed in various ways that reef life utilizes them, a lot of these elements are consumed without our knowledge as we have a very limited range of tests and if we actually took the time to test for every single element with our standard test kits (if there were such testsreadily available) we would be spending thousands of dollars to aquire the test kits then thousands of hours testing..... While none of our artificial salt mixes are perfect there are a fair few that have shown more than satisfactory results in mimicking NSW levels. we are not going to draw out and bandy on about what salt mix is the best here, we shall suffice to say that the choice is yours.

 

[reefkprz]

Other equipment such as calcium reactors and drip systems can help maintain trace elements between water changes, as needed of course. No one wants to sink thousands of dollars into periphial equipment to run a 10gallon nano tank. It would be a pointless and hectic excercise sure to drive people away from the hobby.
..........Macro algaes and detritivors are a great form of utilizing natural means of waste removal, fishes only utilize about 30% of the nutrition available in a food before passing it out as waste. This waste can be used by corals, microfauna, micro and macro algaes, bacteria and such. So having creatures in as many ranges of the food chain as possible in a balance can bring a thriving mini ecosystem into play in a tank as well as creating less overall waste by maximizing consumption of all that is available.
........The overall concept of building a complete food chain gets rather dizzying on the grand scale. But to avoid the dizzying heights of the grandiose we shall limit this to the boundaries or our modest tanks, basicly the key to this in my opinion is biodiversity. That of course begins with establishing populations, getting live rock from more than one source is a good way to provide biodiversity. Preventing predation in the early stages of tank set up is a decent way to allow populations to build. Such as not introducing carnivorous or omnivorous fish untill the tank has been set up for several months can ensure the populations of microfauna get a good head start and build up to self sustainable levels. I even reccomend against running protien skimmers in the early stages of tank set up as it may diminish populations of microfauna.
.........Now, you cannot sustain a thriving population of a great variety of life by feeding one type of flake food every couple of days, the source of nutrition is too limited, too scarce, and not nessecarily utilizable by even a signifigant fraction of what your trying to sustain (wheather you know its there or not), thus it becomes a self limiting factor, less available foods limits the populations of bacteria, microfauna, etcetera, dwindeling the biodiversity to a minimal level in turn making it easier to exceed the upper tolerances for input by reducing the ability to readily consume all available influxes. Rather a slow build up of constant feeding in small amounts increases the tanks available microfauna populations, bacterial colony count, and such by providing ample food to sustain these larger populations. That, coupled with the export of waste and byproducts through filtration, water changes, etcetera.
........Thus, in turn, the natural occuring populations of microfauna and micro or macro algae actually return available nutrition by providing prey for carnivorous fish and natural algal growths for herbivorous fish as well as being physically removed by some of our forms of filtration and acting as a nutrient export or nutrient recycle. The growing of macro algae in situations such as refugiums act as a physical removal of waste by harvesting, thus physically removing the nutrients the plant life has absorbed to grow. Also providing a shelter of sorts for the reproduction of many types of micro fauna.
.........Sand shifting (not sifting) creatures also play a role in export. Some may consume waste but the larger role is to keep the sand bed aerobic. Turning the upper layers feeds the bacterial colonies in the sand oxygen and flow of nitrogenous compounds allowing it to do its "job" in the nitogen cycle.
..........In shallow sand beds this is fairly easy to accomplish, even stirring the top layer of sand with your finger can help maintain the aerobic activity, as well as kicking up detritus and bacteria for corals and other filter feeders to consume. In deep sand beds it is even more important to maintain the upper layers aerobic activity, as in deeper sand beds you want to create anoxic (oxygen poor) sublevels but you do not want to create purely anaerobic activity as (I'll quote Anthony Calfo on his description of anaerobic activity in our tanks here) "All hell breaking loose in a closed system." with purely anaerobic activity the chances of oxygen debt become very real indeed and this should be avoided.

 

[reefkprz]

Over all I believe that for the most part our corals and fish starve for proper nutrition because of lack of proper waste removal. On the whole, I believe for the most part fish are the easier to compensate for, with the simplest techniques being rapid turnover to keep food suspended coupled with ample mechanical filtration thats easy to clean out. Filter sponges and filtration pads that can be removed and cleaned minutes or within hours after feeding to remove any food that has been trapped, signifigantly reducing the amount left in the system to break down. corals are far harder as their needs are far more exact, and less well known. Too often you hear a coral described as "purely photosythetic, doesnt require food" in fact nothing could be further from the truth every bit of research I have ever read on the needs of corals points to at least the animal requiring nitrogenous compounds for its zooxanthellae to utilize during photosynthesis. In my expirience sponges and similar mechanical filtration should be cleaned daily, weekly at the longest stretch, monthly pretty much negates the benifit of such filtration as the waste just sits there in the filter media breaking down polluting the tank.
.......Obviously this little blurb has barely scratched the tip of the nutrient influx and export iceberg there are many subjects within this subject that have not even been given a glance, and with that I look to the future and to each of us as individuals to pool our rescources and knowledge in minor and major advances in techniques, as well as technology, habits, and mistakes. Mistakes are definatly important, if you dont let some one know of a mistake you made they may be doomed to repeat it.

 

[veni vidi vici]

Sticky^
Thanx for sharing that reefkprZ.

 

[cmaxwell39]

Reefkeeprz-- Very well thought out and written article. Makes you realize how vast the ocean that we are trying to mimic is, and how hard it is to do that job (mimicing the ocean). Thanks.

 

[rebelprettyboy]

Great Great post!

Everyone read it.
And def a sticky! Gooj Job man!

 

[reefkprz]

thanks guys! I wrote this in my off time this winter. I wanted to keep going but I wanted it short enough to hope fully not bore people to death so they quit reading it and didnt catch the scope of what I was trying to say.
Overall the intended effect was to get people to look at foods and nutrient removal from a different angle or angles, rather than to actually drill in hard facts. and try and break the cycle of "food-fish-filter" mentality.

 

[nycbob]

thanx for the info.

 

[salty blues]

Great posts. Paragraphs and spaces would sure help though.

 

[reefkprz]

apparantly when cutting and pasting the SWF page removed all my tabs for paragraphs. I should go back through and manually insert them. it does look like one long droning paragraph like that doesnt it.

 

[reefkprz]

there I did that. apparantly the MSG board squishes empty space (tabs) down to non existence as they are visible in edit mode but vanish once posted.

 

[chankanaab]

Thanks for the post.

Would you mind sharing your home made food recipe?
What creature do you suggest for sand shifting in my 100gal 2inch bed FOWLR?
Thank you.

 

[reefkprz]

Originally Posted by Chankanaab
http:///forum/post/2560249
Thanks for the post.

Would you mind sharing your home made food recipe?
What creature do you suggest for sand shifting in my 100gal 2inch bed FOWLR?
Thank you.
for sand shifters the tag team approach seems to work best. nassarius teamed up with sand cleaning cukes works good for me. in your tank I would go 2-3 cukes and half a ton of nassarius.
my recipie shifts but it may contain
cyclops, mysis shrimp, oyster eggs, oyster, clams (merciana merciana), all breeds of shrimp including krill (except decorative), any marine algae unless my fish reject it, mussels, scallop, whitefish, haddock, hake, cod, cusk, salmon (oily), tuna (oily/fatty), swordfish (oily), tilapia, herring, striped bass (or any sea bass), copepods, amphipods, fresh phytoplankton, crab and the list goes on and on.

 

[reefkprz]

there are a lot of simple ways to increase your export to influx ratios,
like making sure you clean your filter pads as often as possible, while they only trap a set amount the faster you get it out and the less time it has to decompose in your system the less overall nutrients get released to foul water quality.
blowing out the holes your rocks with a turkey baster or powerhead just before doing a water change to get as much detritus suspended as possible in the water column not only feeds a lot of your detritus eating corals and other inverts but allow you to remove an amount of it during your water change. as well as getting it suspended for your filtration to get another shot at. this will also prevent blockage of the pores inside the rocks allowing water to flow through the rock letting it do its job as your biological filtration.
keeping your skimmer emptied and cleaned as often as possible, again allows less in system water contact time for the gunk that builds up on the inside of the collection cups tube to break down further re-releasing nutrients back into the system.
increasing water change volumes by 5% will have a rather serious impact over time.
as well as increasing water change frequency, once a week will maintain almost perfect water quality at a 25% volume of change. most people cant get themselves to do that much and for some its not needed or warranted for their systems. myself doing 25% once a week with a 50% change once a month has boosted my growth rate of a lot of corals signifigantly as well as allowed me to feed a higher volume/frequency of food with no noticable negative impact on water quality. I think the boosted growth rate is due to a mix of maintaining high trace elements (through waterchanges) as well as low pheremone levels from fish and chemical warfare/growth inhibitor chemicals from corals (like terpenoid compounds), as well as helping lower the PPM count of shed nematocysts, all of this bundled together makes for a fairly healthy and rock stable system.
of course there is much more you can do.

 

[spanko]

Thank you Erik. Nicely done. We often see the misinformation that feeding coral is not necessary, but we need to keep educating people that this is not so and that coral are continuously filtering nutrient from the water column. That a the importance of keeping rock work cleaned of detritus for proper water flow through the bio filtration and export of unused nutrient before fouling our systems are the two things that I hope most people take away from this article. Again thank you for the well though out and written article.