How exactly is bio load determined?

[jamesucla]

I would say biolode = Grams of Protein fed per day. How much do all the fish eat per day, by weight, x protein % of the type of food.

Look at it as a system with inputs & outputs. In goes food, out goes nitrates in the form of water changes, or nitrogen gas if any anerobic is happening. What happens with the fish activity is immaterial. The vast majority of what goes into the system (aka Tank) is excreted as ammonia & processed by the tank. Exception to that being the amount of protein that is incorporated into the fish as growth, which could be ignored to be conservative. How the fish process the food doesn really matter, it is ultimately converted into nitrates one way or another.

 

[Backfromthedead]

I would say biolode = Grams of Protein fed per day. How much do all the fish eat per day, by weight, x protein % of the type of food.

Look at it as a system with inputs & outputs. In goes food, out goes nitrates in the form of water changes, or nitrogen gas if any anerobic is happening. What happens with the fish activity is immaterial. The vast majority of what goes into the system (aka Tank) is excreted as ammonia & processed by the tank. Exception to that being the amount of protein that is incorporated into the fish as growth, which could be ignored to be conservative. How the fish process the food doesn really matter, it is ultimately converted into nitrates one way or another.

Imo this is only part of the equation. Fish will metabolize and excrete waste even if you are not feeding them. Maybe not as much, but a given type of fish will burn a certain amount of calories just swimming around and breathing.

 

[jamesucla]

Imo this is only part of the equation. Fish will metabolize and excrete waste even if you are not feeding them. Maybe not as much, but a given type of fish will burn a certain amount of calories just swimming around and breathing.

It applies in most normal circumstances and allows one to get an idea of what the filter is processing. Not sure I've heard any better ways to estimate this. Ultimately the tank processes what is put into it, in the form of food, regardless of how many fish there are or what they are doing. Exceptions being fast growth, starving the fish, or if something dies in the tank & starts rotting.

 

[Backfromthedead]

It applies in most normal circumstances and allows one to get an idea of what the filter is processing. Not sure I've heard any better ways to estimate this. Ultimately the tank processes what is put into it, in the form of food, regardless of how many fish there are or what they are doing. Exceptions being fast growth, starving the fish, or if something dies in the tank & starts rotting.

Yes i agree the tank processes what is put into it including...the fish being put into the tank themselves! Putting more fish into the tank will always equal more bioload. In essence, one fish could simply eat another, and that fish would become food.

 

[jamesucla]

Yes i agree the tank processes what is put into it including...the fish being put into the tank themselves! Putting more fish into the tank will always equal more bioload. In essence, one fish could simply eat another, and that fish would become food.

My point is you can treat the fish as a "black box" under normal, steady-state circumstances. Eating each-other, starving, and dying and rotting in the filter would be excluded here. Generally the more fish you have in the tank, the more food you must put in to avoid starving & aggression & maintain steady-state. That food can be measured & correlated water parameter response ( X grams of protein/week = Y ppm nitrates, under Z water change schedule). If you know how many grams/week those fish would be eating, you could estimate the bio-load & how the tank would respond with more fish.

For example if you feed your fish 15 g/week of pellets, you measure your nitrates ppm prior to a regular water change at 10ppm. If your acceptable limit for nitrates is 20ppm, its reasonable to assume you could feed roughly 30g/week with the same water change schedule. This is regardless of the number of fish in the tank, as long as the fish are healthy (It is also ignoring nitrification). Realistically the fish will let you know if you are feeding properly & react. Say you added more fish & need to feed 45g/week to keep aggression under control. In this example it doesn't really matter how many fish you added, you tripled the bio-load from 15 to 45g/week. Point being, this is the easiest way to get some useful, actionable information.

 

[Backfromthedead]

My point is you can treat the fish as a "black box" under normal, steady-state circumstances. Eating each-other, starving, and dying and rotting in the filter would be excluded here. Generally the more fish you have in the tank, the more food you must put in to avoid starving & aggression & maintain steady-state. That food can be measured & correlated water parameter response ( X grams of protein/week = Y ppm nitrates, under Z water change schedule). If you know how many grams/week those fish would be eating, you could estimate the bio-load & how the tank would respond with more fish.

For example if you feed your fish 15 g/week of pellets, you measure your nitrates ppm prior to a regular water change at 10ppm. If your acceptable limit for nitrates is 20ppm, its reasonable to assume you could feed roughly 30g/week with the same water change schedule. This is regardless of the number of fish in the tank, as long as the fish are healthy (It is also ignoring nitrification). Realistically the fish will let you know if you are feeding properly & react. Say you added more fish & need to feed 45g/week to keep aggression under control. In this example it doesn't really matter how many fish you added, you tripled the bio-load from 15 to 45g/week. Point being, this is the easiest way to get some useful, actionable information.

I get your point but i would have to see some actual experimentation and results to confirm it all. If you had two tanks, one with 5 fish and one with 10 fish, getting the same amount of food, I'd still wager the tank with 10 fish carries significantly more pollution at the end of the week.

 

[jamesucla]

I get your point but i would have to see some actual experimentation and results to confirm it all. If you had two tanks, one with 5 fish and one with 10 fish, getting the same amount of food, I'd still wager the tank with 10 fish carries significantly more pollution at the end of the week.

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.

 

[FINWIN]

Interesting. I remember having a thread awhile back mentioning the correlation between types of waste vs water quality. I have jumbo parrots. Two are in identical sized tanks (38 gal). I discovered that one makes more solid waste, the other makes more urine waste. The urine waste trumps...it created more issues with nitrates and ph crashes than the solid stuff.

Brings to mind what was said about 'invisible pollution' where the water looks crystal clear. But then, so does Vodka.

 

[Niki_up]

My point is you can treat the fish as a "black box" under normal, steady-state circumstances. Eating each-other, starving, and dying and rotting in the filter would be excluded here. Generally the more fish you have in the tank, the more food you must put in to avoid starving & aggression & maintain steady-state. That food can be measured & correlated water parameter response ( X grams of protein/week = Y ppm nitrates, under Z water change schedule). If you know how many grams/week those fish would be eating, you could estimate the bio-load & how the tank would respond with more fish.

For example if you feed your fish 15 g/week of pellets, you measure your nitrates ppm prior to a regular water change at 10ppm. If your acceptable limit for nitrates is 20ppm, its reasonable to assume you could feed roughly 30g/week with the same water change schedule. This is regardless of the number of fish in the tank, as long as the fish are healthy (It is also ignoring nitrification). Realistically the fish will let you know if you are feeding properly & react. Say you added more fish & need to feed 45g/week to keep aggression under control. In this example it doesn't really matter how many fish you added, you tripled the bio-load from 15 to 45g/week. Point being, this is the easiest way to get some useful, actionable information.

Something missing from your equation is rotting plant material which will also add ammonia and will be different for each tank as to weather or not a person has them and the quantity.

I believe the only way your measuring would work is if someone kept fish in an aquarium with out decor, plants, or substrate.

 

[jamesucla]

Something missing from your equation is rotting plant material which will also add ammonia and will be different for each tank as to weather or not a person has them and the quantity.

I believe the only way your measuring would work is if someone kept fish in an aquarium with out decor, plants, or substrate.

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.