A confusing question about biological filtration, need help.

[coldfusion]

Hey
This may sound like a stupid question and I’m sure my style of explaining it combined with my examples confuses people, but I’m interested in how biological filtration works. I know the basics of it, but I’m somewhat confused to if it works on equilibrium or just shear surface area.
IL explain, When in the first stage of biological filtration, the Nitrosomona bacteria consume the ammonia and convert it into nitrites.


1.Does this work by say,(numbers are just for example) ammonia is at 20 units, so the Nitrosomona bacteria grows to 20 units to compensate this, even if the Nitrosomona bacteria have the surface area to grow to say 40units?

2. Or is it based on the concept of the filter has the ability to grow say 50 units so it will grow 50 units regardless if the ammonia is at 2 units or 70 units?



If in the first example is true, how then does adding a fluidized bed filter help on an established system? If the filter that is in use provides that equilibrium then wouldn’t that leave the FBF pointless? Or is the load shared between all the available surface areas?
If the second example is true doesn’t that go against some of the concepts of fishless cycling? E.g. if I have a new 4 foot tank with a filter that is designed for the 4 foot tank with has the ability to say make 50 units worth of Nitrosomona bacteria. I then add after the filter has been operating for a week , one small guppie that produces 1 unit of ammonia, wouldn’t the filter make 50 units of Nitrosomona bacteria even before the guppie is added, seeing though the filter has the capacity of 50 units of Nitrosomona bacteria? Therefore not generating that sort after “ammonia spike” at the start of a new system?


One last question. Also a little bit off topic, with a FBF if you added a air stone to the filter so that the water is even more aerobic, would this be more beneficial or less beneficial to the FBF in terms of biological bacteria?

Sorry for the length and if I’m asking a question that has already been answered.

Cheers clint

[Barrie]

Clint my understanding is that with all living entities, the population numbers are determined by the amount of food that is available, in this case the ammonia produced for the bacteria to live on. So I agree with your example 1. Having said that though the population size of the bacteria colony also requires a certain amount of space to colonise and the ability to be able to increase (or decrease) as the demand requires.
I agree that if a filter is already coping with a certain bio load then adding another is not going to make any difference with regards water quality but it gives you the opportunity to clean the filters at differing times so that you don't wipe out your whole bacteria colony.

[ILLUSN]

1.Does this work by say,(numbers are just for example) ammonia is at 20 units, so the Nitrosomona bacteria grows to 20 units to compensate this, even if the Nitrosomona bacteria have the surface area to grow to say 40units?


this is correct

adding more filtration just means more surfaces for bacteria to grow and more room for expansions in the case of an ammonia spike. also bacteria will "share" its self over all available colinisation surfaces.

if you add established media to a new tank, add fish asap, or as you've said the established media will die from starvation, even if it does i sware it leave spores behind which help recolonise when ammonia is added. again

you could add an airstone to a fbf but it wont doo much, O2 enters the water from the surface, most fbf's are sealed so bubbling in the canister will do nothing, i added an airstone to my open top fbf's and didn't see any real improvement, on my 2m tall unit i actually got better water quality when i removed the airstone and sand and replaced it with matrix as then the filter had a denitrate effect (2m tall 90mm wide with a flow rate of 600l/h) on the tank.

[Barrie]

[Quote........ will die from starvation, even if it does i sware it leave spores behind which help recolonise when ammonia is added. again..... Quote]


Thats correct ILLUSN. As well as the spores some bacteria are capable of entering a state of suspended animation allowing themselves to lie dormant for long periods of time until favourable conditions are once again present. There have been discoveries where bacteria have been found in this state after many thousands of years.
Have a read here Clint. http://www.daviddarling.info/encyclopedia/B/bacteria.html
Barrie

[ILLUSN]

nice link Barrie!!!!

thought so even old old media seems to cycle ALOT faster then new media every time i pull some out of storage.

[Old Dave]

..., on my 2m tall unit i actually got better water quality when i removed the airstone and sand and replaced it with matrix as then the filter had a denitrate effect
(2m tall 90mm wide with a flow rate of 600l/h) on the tank.

:shock: :shock: :shock: !!!

Old Dave
:mrgreen:

[coldfusion]

thanks everyone for the help, i understand now.
so if i was to buy a new huge! filter and put it in a new tank (no fish)and add a large amount of ammonia, and let it cycle through. Then add that filter after 36 days of cycling to a smaller established tank, some of the bacteria will die but remain dormant until there is enough ammonia for the dormint bacteria to "feed" again?

thanks illusn, im thinking of investing in a FBF, do you think i should make one or just buy one? i seem to preety handy with the diy stuff.
oh and 2M TALL AND 90MM WIDE!!!! thats huge!!!!
wouldnt mind seeing pics of that bad boy right there lol.

[ILLUSN]

lol will post pics its just 90mm storm water pipe with a few fittings a reducer and an eheim compact 1000l/h pump. will get photos up for you.

[ILLUSN]

as requested heres a photo of my 2m monster, its 2 m of 90 storm water pipe, a few connecters a 90mm "T" a 90mm-40mm reducer and a few 40mm elbows. To give you an idea of scale thats an eheim 2028 at the bottom filtering the 4x2x2 tank below the 6 footer

Water is pumped via an eheim compact 1000 up about 30cm of 16/22mm hose then into 15mm pvc pipe down to the bottom of the filter, here it rises up through 8L of matrix before cascading back into the tank, the flow rate is low only 650L/h, so it turns the tank over once an hour, this filter has reduced nitrate in my system from ~40ppm to below 20ppm.

the tank gets top ups once a week to replace water from evaporation and a propper clean and 50% change every 6-8 weeks.

an eheim pro 3 2080 is also running on the tank and its densly planted

[ILLUSN]

for anyone who's keen i did a quick DIY on how i build these filters, depending on size you can put a 1m tall one together for under $30 (without media and pump)

http://www.discusforums.com/forum/viewtopic.php?t=19904&highlight=

[coldfusion]

thanks illusn. that thing is massive!!
i would of thought with 8L of matrix, it would of done more of an effect to the nitrates.
8L of matrix must of cost u a fortune.
would you ever consider putting a UV filter onto the end of the FBF? to make it a lil tidier, or do you want even slower flow rate for a UV filter?

[ILLUSN]

LOL sorry mate didn't see your post, a 50% NO3 reduction is massive, as you can see the tank isn't well maintained and with 11 XL angels, 4 Lg clown loaches, 10 L to XXL bristlenoses 50 glowlight tetras, 20 ember tetras its a little over stocked.

will test some water comming out of the FBF tonight and vs water from the tank to see if theres a measurable diffrence before and after the filter.

as for a UV at 650l/h a 36w would do the job nicely, I wouldn't bother with one for and angel/tetra tank if it were a discus tank it would be worth it, as the 16mm pipe comes from the tank to the top of the filter plumbing one in might be tricky but if you were creative enough you could do it.