Types of biological flitration.

[Oughtsix]

After reading through (most of) SantaMonica's "Mega Powerful Nitrate and Phosphate Remover - DIY" thread I find it VERY interesting.

Am I correct in my understanding that biological filtration can be broken down into 3 basic classes:
1) Bacterial - Either aqueous or semi aqueous.
2) Algae - As described in http://www.monsterfishkeepers.com/forums/showthread.php?t=180385
3) Plant - Either aqueous or terrestrial.

When I think of #1 I think of biomedia in a canister filter, bateria that grows within the tank itself or a wet dry trickle filter with bio balls, scrubbies, etc.

When I think of #2 the above mentioned post is my first exposure but algae simply growing in the tank would be another form of this filter.

When I think of #3 I think of a planted tank or terrestrial plant filter... hydroponic type setup.

So what are the pros and cons of each of these methods of biological filtration? Do some excel in one area removing a particular contaminant and others in other areas?

I am just setting up a 110 gal Cichlid tank and I was really enthusiastic about a terrestrial plant filter with Pothos and Lucky bamboo. My main motivation for a terrestrial planted filter is appearance. And maybe trying to grow strawberries.

Would a terrestrial plant filter remove the same contaminants as a Mega Algea filter? It sounds like the algae filter has a major benefit as far as space efficiency but does it have any advantages as far as quality of the filtered water? With an Algae or terrestrial plant filter is there no further need to make specific provisions for bacterial filtration (bio media or trickle filter)?

I am thinking along the lines of fresh water. Would things be different for salt water? Obviously terrestrial plant choice would have to be different... i.e. mangroves but wouldn't this carry over to the species of bacteria and algae that would flourish?

It would seem to me that all three of these filters would compete for similar resources????? Hence the effectiveness of the Mega Algae filter at keeping nuisance algae out of the tank. Would a Terestrial plant filter also be effective to some degree at reducing nuisance algae? And wouldn't a Mega Algae filter stunt the growth of aqueous plants in the tank?

 

[jcardona1]

Plants and algae will consume all of those nutrients. The problem is, it would take a very large plant/algae filtration system to keep up with the bioloads of the large fish people on this site keep. It simply isn't feasible or practical, hence #1 is always the most efficient form of filtration.

 

[Noto]

Plants and algae consume any type of nitrogenous waste, and in most cases preferentially consume ammonia. Therefore they reduce the need for water changes, because they do not leave nitrates behind. As Jcardona1 mentioned, they tend to take up more space, but some really powerful algae scrubber-style setups are quite compact. Plants and algae also require lights.

Plants and algae cause a net increase in dissolved oxygen when photosynthesizing, which is beneficial to fish. Bacterial filters consume oxygen. However, plant filters are also net consumers of oxygen when lights are out.

 

[Oughtsix]

So after much reading my understanding is that aerobic bacteria (with O2) will process Ammonia into Nitrites and then into Nitrates.

Nitrification is the conversion of ammonia to nitrate through biological oxidation. Nitrosomonas aerobic bacteria convert ammonia (NH3) to nitrite (NO2-) and Nitrobacter aerobic bacteria convert nitrite (NO2-) to nitrate (NO3)

So nitrates which are less toxic to fish will build up in our tanks and should be removed by:
1) Water changes
2) Nitrogen uptake by plants
3) Nitrogen uptake by algae
4) Denitrification by bacteria (Sulfur or Alcohol fed nitrate reactor)
5) Nitrate absorbing resins

Denitrification is the process through which anaerobic microorganisms convert nitrate back to nitrite, and then to nitrous oxide, nitric oxide and dinitrogen. Dinitrogen escapes to the atmosphere to rejoin its friends and family, and to await fixation. Some nitric oxide and nitrous oxide may remain, but dinitrogen is the main product of denitrification.

reference: http://www.freshwatermadness.com/Ammonia-and-Nitrites-and-Nitrates-Oh-My-Part-1-h52.htm

From what I have read some people have designed self contained crucibles for denitrification based around an oxygen free chamber for the anaerobic bacteria to flourish while being fed by sulfur or alcohol. These are referred to as "Nitrate Reactors". From what I have read these Nitrate reactors are pretty temperamental to operate and take a lot of attention to maintain the proper conditions for anaerobic denitrifitation. They also produce acidic PH reducing water which then has to be processed before being released back into the tank. This doesn't have much appeal to me.


For my 110 gallon cichlid tank I am still favoring removing nitrates with a terrestrial plant refuge. My thinking:
a) I will do water changes and I am really considering a continuous drip water change system but I would like to deploy a more self sustaining system.
b) The Mega phosphate and Nitrate removing Algae filter seems very efficient, can be made relatively compact but weekly removing the plate and scraping Algae off of the plate to be discarded doesn't have a lot of appeal to me. I suppose I could look into using the algae as mulch in my garden but the whole maintenance cycle seems like a lot of trouble.
c) Nitrate adsorbing resins seem to be more of a temporary solution good for addressing an immediate critical situation. They would be expensive for long term use. Constant testing would be needed to know when the resins are exhausted and when to change the media. I believe I read that upon saturation the resins can actually release Nitrates back into the water causing a spike?
d) I like plants!
e) Aquatic plants can be a challenge with cichlids.

This brings me to the the terrestrial plant refugium. Have I missed something with my logic? I am running a Eheim 2276, Fluval 404, Magnum 350 and put an old Emperor 400 biowheel on the back of the tank. The Eheim and Fluval should provide plenty of biological filtration and should make good Nitrate factories. What I am unsure of is the need for these Nitrate factories. A well functioning terrestrial plant refugium should be able to asorbe and process the raw ammonia and bypass the whole Nitrification bacteria cycle... shouldn't it?

 

[619aquaponics]

People generally use algae filters or algae scrubbers for 2 reasons
1 they take up less space
2 they can be used on salt water systems
Terrestrial plant filters work just as well but take up more room. If you want to grow strawberries that would be called aquaponics. I have an aquaponic grow bed on my heavily stocked 30 gallon and have 0 ammonia nitrates and nitrites. As a bonus I get fresh kale and lettuce

 

[Oughtsix]

Hello 619aquaponics,

From surfing terrestrial plant filters I just found my way into aquaponics. Very interesting reading! I am pretty certain this is the way I want to go... for fun more than for production. I current have many pothos cuttings wedged between my spray bar and the side of the tank. A couple are rooting already... after being there for about 3 days. I have no clue what to do with them long term as I already have more potted pothos than I know what to do with. My sister will be bringing spider plant starts to add to the mix the next time she visits to add to the mix. Both my kids (6 and 7) have embraced my interest in aquariums and my love of plants which would make the project that much more fun.

Would you mind sharing the configuration of your system? Do you use a medium for your plants? How is it laid out? What is the population of your 30gal tank? What is the size of your plant bed? What other filtration is on your tank? Do you have any pictures you could share? How do you start the seeds for the lettuce?

I have been considering a planting tray suspended directly over my tank. A small power head to supply water and then let it simply drain back into the tank. Moving the tray for tank maintenance is my biggest concern. I have been envisioning a few pulleys and some line to simply raise the tray out of the way when I want to get at the tank. I was thinking of mounting some high power LEDs on the bottom of the tray for lighting the tank (fish only). I will have to come up with something visually appealing and a relatively high WAF (wife acceptance factor)!

 

[jcardona1]

Just a question, are you looking for something to consume all your nitrates and eliminate the need for water changes? Because that's not a really good idea in the long run. Reason being, not adding fresh tap water to the tank will cause your buffering capacity (kh) to get absorbed. Once that gets used up, the tank is left susceptible to wild ph swings.

Constant water changes are essential for maintaining alkalinity. A small drip system along with some plant filtration would be ideal. This would most likely give you 0 nitrates while still maintaining your buffering capacity along with other essential minerals found in tap water.

 

[Oughtsix]

Just a question, are you looking for something to consume all your nitrates and eliminate the need for water changes? Because that's not a really good idea in the long run. Reason being, not adding fresh tap water to the tank will cause your buffering capacity (kh) to get absorbed. Once that gets used up, the tank is left susceptible to wild ph swings.

Constant water changes are essential for maintaining alkalinity. A small drip system along with some plant filtration would be ideal. This would most likely give you 0 nitrates while still maintaining your buffering capacity along with other essential minerals found in tap water.

I have a 3/4" bulk head and a diamond saw on its way to drill the tank for an overflow... this is the only way I feel comfortable doing a continuous drip system. I didn't know exactly why I would still need to do water changes, but I have always planned to do the drip system... now I know. Thx!

I have an empty 35 gal hex I am going to practice on for the drip system. My 110 gal is in a temporary location... waiting for me to finish laying a tile floor in the kitchen. I will drill the 110 when it is broken down to move it. I will also be building a new stand to replace the sorry particle board stand the 110 is on now at the same time the tank is moved. This leaves me a lot of flexibility to design the stand to suit the aquaponics system.

 

[jcardona1]

Here's the drip system I made for my old tank. Real easy to set up!

http://www.monsterfishkeepers.com/forums/showthread.php?t=303090

 

[Oughtsix]

Here's the drip system I made for my old tank. Real easy to set up!

http://www.monsterfishkeepers.com/forums/showthread.php?t=303090

Thank you for the link... only I have already through your thread and it is one of the threads that convinced me that a continuous drip system is the way to go!

I am not sure about a sump though. There is a store bought sump on my local CL currently for $30... that I have sent an e-mail on already. It is from a saltwater tank that was taken changed into a lizard cage and is setup as a trickle filter with a bunch of bio balls. The price is cheap enough. I guess the bio-filtering capacity couldn't hurt?

P.S. I have very clean well water which should make a drip system even easier.