Poser on Biological Filtration

[Bruce]

Assuming that a low-bio-load-and-high-water-change fanatic keeps 1 adult discus to each 20 gallons of water, changes 90% of it every 8 hours, and feeds very moderately and siphons up all uneaten food & feces 5 minutes after every single feeding;

Can a biological filtration culture ever really develop? What would be the point in having any kind of biological filtration device in this scenario?

I don't know anyone like this but would like to learn the theory behind the need to culture beneficial bacteria.

thnx

[ronrca]

Theoretically, probably not! There would be no ammonia/nitrite for the bacteria to feed off of.

In the real world, it may be a different story. First, if you have chloramines and treat it, ammonia is left behind. The bio takes care of that. There's also the possiblilty of not getting all the waste (some getting suck in prefilters and filter media).

So, basiclly, why take the chance! ;)

[Carol_Roberts]

. . . and in a perfect world you could run a constant stream of fresh water through the tank all day, vacume up waste and you wouldn't need a filter either. Unfortunately I don't live in a perfect world so I rely on filters as a back up to water changes and tank cleaning.

[Dave C]

Of course there would be nitrifying bacteria. The fish would be creating urine & fecal matter 24/7. The food would be breaking down the second it hit the tank. There wouldn't be much ammonia in the water but it would be there and there would be bacteria to eat it. The amount of bacteria is dependent on the food available. But once the colony is established it can grow very fast to accommodate an increased amount of food. Therefore it makes sense to me to have a biological filter in all of your tanks. You never know when you'll need it.

[ronrca]

Well, yes! In the real world you will have bacteria growth and I agree, why not have it just in case!

In the first post though, you probably will not as 90% of the water will be changed every 8 hours. Bacteria will not have much of a chance to colonize and reproduce within that time. Even if there were to be bacteria present, it would make no impact on the tank. But, this is only a theoretical situation in a perfect world.

Forgot to answer Bruces question! :)
In order for bacteria to culture, 02 and food is neseccary. Once the bacteria senses food, it 'finds' a place to culture. Then, the process begins! Interestingly enough, bacteria does not culture immediatly in the presence of food. There is a certain time span that food must be sensed before culturing. If food is only present in short intervals, then multiplicaion is slowed therefore a constant food supply is necessary. Bacteria start dividing at around 8 hours.

[Dave C]

Well I would disagree with some of the points you made. I received 4 4" Alenquers from Mike Wells a couple of years ago. I had just overcome Columnaris so I wasn't going to use any of my sponges so I just put them in the tank with a brand new filter. I changed 75% of the water 3x a day. In a week I had ammonia sufficient to make the water go cloudy and I had to risk adding one of the sponges from my other tank. So 8 hours was plenty of time for ammonia to become a risk to the fish.

The point I was making was that the bacteria would form. Whether it has an impact on the tank is irrelevant. It would have an impact on the tank if you stopped changing the water, that's what makes it worth having a biological filter in the tank. Bacteria doesn't culture immediately in the presence of food, it must be seeded to form in a reasonable amount of time. Therefore by having a sponge filter in the tank regardless of how much water you're changing is, in effect, seeding the filter. In time it will have a bacteria colony and if you ever need it you will be further ahead then if you added a new sponge to the tank when it was needed. Under optimal conditions Nitrosomonas double in pop'n every 7 hours and Nitrobacter every 13 hours.

[dred]

Bruce,

Just to let you know, this isn't a hypothetical. Where water is abundant and cheap folks do not use deliberately placed filters. I say deliberately placed because the bacteria will colonize something, but without a deliberate flow across a bacteria colony the colony isn't effective.

Many of us have discus who were spawned or hatched in filterless environments with Constant water flow. Ponds, tanks on dripper/overflow, etc. If you want to read about it, look at the Asian hatcheries - you won't need to look long. Where water is free and clean the filterless system "can" more accurately approach the native environment. All one needs to do is meter the water flow to keep the toxins in check - getting toxic, increase flow.

hth,
milton

[ronrca]

Well, at least we agree on having a filter in the tank! ;D

Very interesting case dave! Tell me why the ammonia build up if your wc 75% 3x a day? What size tank, what feeding maintance routine?

[Dave C]

I don't know why the ammonia built up. It just did, the fish wouldn't tell me why. It was a 28g tank, normal feeding, about 4x a day, nothing excessive.

I would think that at some point you would stop doing such massive water changes with adults....especially if you're trying different things(to get them to spawn) like not changing the water for a couple days, followed by a massive water change...In that case, it would probably be a good idea to have some sortof biological filtration...I have most of my tanks on a drip, but if I turned up the flow of water enough to ALWAYS keep my water clear/clean when I've got a tank full of fry, then the heater would never catch up enough to keep the water warm...so I do supplementary water changes, and I use sponge filters...

[ronrca]

Well, it dawned on me this morning! :o

Dave is right! Eventually you will get bacteria growth! Why? I was thinking about Dave's experience and why the ammonia would build up. When not replacing all the water, 100%, some ammonia will be left over.

Example:
In Bruce's scenerio, changing 90% every 8 hours amounts to 3x a day. Lets say during the 8 hours, the ammonia were to ammount to 1ppm (example). Wc time and you replace 90% of the water leaving 10% remaining. This 10% then is diluted with the new water and the ammonia is still present, lets say the level goes down to .01ppm. Over the next 8 hours, the ammonia produced will be around the same as the previous 8 hours therefore just before the next wc, the ammonia level will be around 1.01ppm. Then the water change, ammonia dilutes to .02ppm, after 8 hours-1.02ppm, wc-.03ppm and so on.

So, over time, the ammonia levels will increase therefore bacteria will grow to consume it. This is why we cycle our tanks even if we are doing massive water changes. (now why didnt I think of that sooner). ;)

[gretag]

hi all, i just got my first discus last sunday. its a 50 gal tank with 5 2.5 inches discus and i've been doing 30% waterchange daily while doing the siphon. before i put in the fish i've done fishless cycling with 5mg/l ammonia per day, will i lost a great amount of beneficial bacteria? what if i do once/ 2 days 50% waterchange? is that ok? i have another hobbyist here told me that if we spoilt our discus they will get weak, is that true?

i feed them 4 times / day, 8 in the morning 12 , 5 and 9 at night, with beef heart, frozen bloodworm and tetrabit, and they only finished the bloodworm, they eat the beefheart very slowww, the dont really like tetrabit, which kind of food is actually the best for them? is it ok to just feed them FBW?

thanks, sorry if i ask alot

[ronrca]

Hi gretag, Welcome to simplydiscus!

You are doing good! Keep it up!

will i lost a great amount of beneficial bacteria?
the bacteria will grow as big as needed (ammonia/nitrites). Depending on the size of the biofilter that you build up when doing your fishless cycle, it will either grow or become smaller depending on how many fish you put in the tank. The main concern though is you do not want any ammonia or nitrite levels at anything. If this is the case, good for you. I would not worry about losing any bacteria then.

What the water changes! Imo and Ime, younger discus do good when you do water changes at least twice a day. I usually do around 50-90% each time depending on the size. For 2.5" discus, I do around 75% twice a day.

Keep feeding them like you are! Even if they do not like beefheart or tetrabit but still eat it, I would still feed them anyways. A varity of foods is better than just 1 type.

HTH! ;)

[ronrca]

You think so? Nah!
My tanks (4 at the moment soon to but 6 ;D ) are setup so that its really easy. I get up around 15-30mins before I need to, turn a valve, flip a switch, turn a valve, turn a valve, turn a valve, flip a switch and turn a valve. Exactly in that order! The same happens in the evening. Takes around 15mins without wiping and 20-25 with wiping!

[Dave C]

I'm with you Ron but your numbers are out.

If your fishload produces 1ppm of ammonia every 8 hours you will drop it to 0.1ppm after the first water change. You indicate that it would drop to 10% and then be further diluted with the addition of clean water. What actually happens is that it stays at 1ppm after the water is removed (just 1ppm for a smaller body of water) and then is diluted by the new water... so your 1ppm for 1/10 of the tank become 0.1ppm for the entire tank after the water change. Over the next 8 hours it would then rise to 1.1ppm. After the next w/c it would drop to 0.11, then rise to 1.11 etc. In time it would level off at a max of 1.11111111... If you look at that as the max value and the minimum being the 0.111111111 after the w/c you'll see that on average your water has 0.61111ppm ammonia assuming that your fish are producing 1ppm every 8 hours. If you did only one daily w/c your fish would be living in water with an average of 1.833333ppm, or 3x the amount. The issue of exactly how much ammonia is produced is not relevant in my opinion. If you did daily w/c your fish live in about 1/2 of their daily production of ammonia. If you did 3x daily w/c your fish would live in 1/6 of their daily ammonia production. My guess is that with biological filtration the tank would have far less then the 0.61111ppm we arrived at in this example.

[ronrca]

??? Im confused! LOL! ;D

A yes! I see! I was adding them up for some reason! :P

But how did you get 0.6111111ppm average?

[Dave C]

If it drops to 0.1111 after the w/c and rises to 1.11111 before the w/c then the average is 0.61111 i.e. (0.11111 + 1.11111)/2 = 0.61111.

[ronrca]

But of course! :P (max+min)/2
Thanks Dave!

I guess it really doesnt matter what the numbers are! The main concern is that ammonia will build up over time if no bacteria is present (tank not cycled)! ;)