How exactly is bio load determined?

[esoxlucius]

It's all very complex and scientific but I suppose there is a very crude way of getting an idea what bio load a fish puts out, and one that can be measured, sort of. It's also probably flawed to hell but i'll have a stab at it. Lol.

If you had a single fish in a cycled bare tank with just a filter and a heater and did a huge water change, and then measured the nitrate straight after the water change. It would help for the sake of these experiments that your water change was very large so to try and achieve 0ppm.

Then, don't feed that fish for a week, absolutely nothing. And then test your nitrate after that one week without food. I'd have thought the resulting nitrate reading would be low, not 0ppm, because the fish, just by living is giving off bio load.

Then do another huge water change, back to 0ppm again. But for the second week let's feed the fish say 1g of pellets a day. Do this for a week and then test the nitrate. Huge water change, nitrate back to 0ppm.

The third week let's feed 2g of pellet a day, and so on and so forth. You can carry on feeding more heavily as each week passes.

At the end you'd probably have a set of results that would give you some sort of a pattern and maybe give you some kind of an understanding of what feeding can do to bio load, who knows.

But like I said it's a very crude test and there will be lots of other variables at play.

 

[DRUKENMUNKY]

I honestly am glad that there is no way measure bioload....at the end of the day....even if there was concrete info on bioload ..even those results would not be accurate for long. The fish will continue to grow , feeding schedules will change, tank conditions will change all with time. If people had an idea that they had enuff filtration it might sway them into a comfort zone where they think they are fine. Good old fashioned testing and over filt er ing is the way to go not just for my current parameters but for future add ins and growth. On a different note though what I have noticed popping up is more and more threads with people having horrible water out the tap in their areas. With this most people of course just change water when nitrate get high but I would like to learn more about anaerobic filtration for thise who dont have the luxury of good tap water and looking for ways to not change water so often...i know everyone is gonna mention pothos and plants of course but recently i have been trying to find info on building anaerobic bacteria using newer modern media, reduced oxygen reactors, deep sand beds that type of stuff and have very little info on the subject.

 

[Niki_up]

What would you suggest, in the absence of measuring food in & comparing to water parameters? What I'm suggesting is not really an equation but more of a correlation. Without that you are really just guessing. At least this gets you in the ballpark enough to make other decisions, like water change frequency & how much fish you can "afford" to feed vs water quality.

Sorry I have no additional input really. I can’t even pretend to think I know a mathematician solution. Just thought of the waste plants produce when they die and wanted to put it out there.

Personally I just do my weekly water changes and visually monitor my tanks, when I see changes I do testing.

 

[neutrino]

A lot of good thoughts above. The main thing I agree with is there are far too many variables to settle on a general formula applicable to the wide range of species, tank conditions, foods, and other differences from one fishkeeper to another. For example, just on the feeding side, what ingredients are in the food, how well are they assimilated, what are the protein levels, what effect on intestinal health (as one example among several for this, soy can cause intestinal inflammation, some versions or components of soy more than others), what % of feed is converted to growth and what % is converted to waste-- this varies with species, ingredients, protein %, environmental conditions, etc.

There is a lot of aquaculture science done on this, effect of different ingredients, formulas, and protein and lipid levels on growth vs. waste production, etc, but these are done under controlled lab conditions. Even at that, comparative results can vary depending on the baseline (control) formula they're using.

On the practical side for an average aquarist, along with, or as an alternative to, testing nitrates, you can judge a lot by the effect on filters and maintenance. Everything else being equal, a higher bioload will affect how quickly your filters get dirty.

 

[Backfromthedead]

So do you have a better starting point for estimating bio-load, as opposed to the amount of food you intend to feed? At the very least, my way is measurable. Perhaps I will do that on my tank, in the name of convincing people on the internet, haha.

I tend to think of feeding as a constant, whereas the size and metabolism of a given fish can be variables. For instance, a large adult cichlid will burn more calories in preparation to breed, or also, if given an abundance of food, a large catfish may store more of this food in fatty deposits vs. Burning it off. Many more physiological variables in play here than variables related to feeding. And besides, in any conversation concerning "bioload", its a matter of fish type and size and the tank theyre in...feeding frequency is more an issue of proper care and husbandry.

 

[jjohnwm]

Interesting thread. I certainly agree that the number of variables is so staggering that almost any formulaic approach to quantifying bioload is pretty futile. Even if some standardized method were adopted, something that allows each and every tank to be given A Number...what purpose would be served, aside from simply allowing comparison between one tank and another?

Another problem that seems, at least to me, to be very difficult to account for is the time factor. What is the length of time over which The Number is being measured and calculated? I have in mind a tank of mine containing an ever-expanding breeding colony of Goodeid livebearers. They eat prodigiously, and their tank tends to be spotlessly algae-free, despite my best efforts to provide bright lights and extended photo-periods to encourage algae growth. I throw in handfuls of Hair Algae whenever I can produce it, and it quickly disappears.

So let's say we have a tank with a luxuriant growth of Hair Algae and an established population of assorted fish, and a small number of these Goodeids are introduced. Obviously, they add to the existing bioload of whatever other fish the tank already contains. Over the following days/weeks they mow down the algae, metabolizing it like any other food. If during this period of time I continue to introduce the same amount of food per day that I did before these fish were added, any of the bioload-measuring methods suggested above would say that there is no increase in bioload, which is patently false. There's more fish in there, and they are all breathing and eating and pooping...but they are using nitrogen that has been locked up in the tank for extended periods in the form of algae. How do you measure and quantify this? What period of time gives a meaningful Number? A week? A month? I personally suspect that the monitoring period would need to be something along the lines of several months to really mean anything.

And more importantly...why bother? Aside from information for information's sake, what benefit can we glean from knowing another Number? There are lots of aquarists who buy test kits, chemicals and reagents in bulk, and who can rattle off their pH, GH, TDS, KH, etc at the drop of a hat...and who still somehow struggle to keep fish alive and healthy. I have a friend who probably doesn't need to do a single water change, because he dips so much water out each week for tests that just replacing it gives him sufficient fresh water. He is currently celebrating because he has a fish...a single fish...his first fish...that has managed to live for a whole six months, while dozens around it have succumbed to various maladies and problems. I don't even want to show him this thread; it might push him over the edge...

The Science of aquaristics is as important as the Art; we need to have a decent grasp of both to be truly successful.