thread for bioload calculation

shern

Plecostomus
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Oct 17, 2023
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Greetings all, recently i’ve been reading up on some older threads and forums on how bioload of a fish is calculated and with that, all the nuances of filtration. commonly thrown around is the gold fish for example which has a much larger bioload per “inch” due to its habits of eating much more than what you feed and you can see. Is bioload an actual calculation that’s made when regarding specific fish species or is it more dependent on your filtration? For example i run two fx6s for my 250g and though the label on fluval products states its able to take in 400g~, i’m unsure to the limit in which the fx6 can handle. is there any set way to measure and or quantify how much bioload a fish would produce and how much your tank and filters can take before your ammonia becomes uncontrollable?


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esoxlucius

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You are overthinking this. There is no calculation, there are wayyyy to many variables. Stocking levels, size of fish, type of fish, feeding regime, water change schedule and overall volume of water all play a huge part in bio load.

Doing some kind of calculation for just one of those variables is nigh on impossible, let alone a bunch of variables in play simultaneously.

To keep it as simple as possible, in a way that isn't going to make your head explode, if your bio filtration is keeping ammonia levels at a consistent 0ppm you're golden. That's it, headache over!

And as long as you're doing regular water changes to keep the resulting nitrate at sensible levels then all's good, you have a good bio system in place.
 

duanes

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Agree with esoxlucius, once the tank is cycled,, the only way to judgeis to test for ammonia and nitrite.
If there is enough media, before and after after a water change, tests will be negatice,
if there is a trace of ammonia, after a wa6ter change it may be due to the addition of chloramines (but only a trace, abd soon ofter, the media should take care of that trace).
The only measurable componant, is testing nitrate.
With an adequat schedule.....
If after a regular water change routine, nitrate concentration should no higher than 5 ppm.
If not, ...either that water change routine is not frequent enough, or not enoughwater is being changes.

You can supplement a lax routine by using heavily planted refugiums, tanks, or terrestrial growth.

When using onnly standard biomedia,
I determined thru a series of tests (that with my average stocking levels, for medium size, long lived cichlids)
my tanks needed every other day 30% to 40% water changes to maintain safe nitrate levels to prevent diseases like HITH, and hypoxia
.Exposure to Nitrate Increases Susceptibility to Hypoxia in ...The University of Chicago Press: Journalshttps://www.journals.uchicago.edu › doi

By employing heavily planted refugiuns, I could reduce those water changes by about 2/3rd per week..
IMG_9885.jpegIMG_9456.jpegIMG_9887.jpeg

But each aquarium has its own set of needs, so a series of tests are needed to determine what those need sre.
If one keeps short lived air breathing Anabantids, or tetras that max out at only 3 years, chronic diseases may not be a concern.
But if the goal is to maintain long lived cichlids, such as oscars, Geophagines or severum that are prone to HITH (if kept in conditions such water pH or hardness)
not evolved to resist chronic pathogenic bacteria in), then nitrate reduction becomes much more of a cercern
 
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Backfromthedead

Potamotrygon
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Jul 12, 2017
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I have not so much a calculation but more of a estimation technique. To me its simply a function of feeding, fish size, and fish metabolism/activity. While theres no doubt more factors at play i think these are the most influential, and any measurable increase or decrease of them should reflect in your water quality.
 

troublesum

Dovii
MFK Member
Dec 28, 2007
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Astoria, NY
I am obsessed with water quality i always worry about my water if i see one of my fish do something i haven't seen before (flashing on a rock) i freak out.]
My only piece of mind is doing 3 large 80% WC as week
i only have a 125 with a FX6 and 2 XL sponge filter 1 fish is 8.5-9in the other is 10.5-11in i feed medium size pellets and very lightly 1X a day.
I would quit trying to be scientific and just do WC when ever you start going down that rabbit hole
 

shern

Plecostomus
MFK Member
Oct 17, 2023
253
125
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You are overthinking this. There is no calculation, there are wayyyy to many variables. Stocking levels, size of fish, type of fish, feeding regime, water change schedule and overall volume of water all play a huge part in bio load.

Doing some kind of calculation for just one of those variables is nigh on impossible, let alone a bunch of variables in play simultaneously.

To keep it as simple as possible, in a way that isn't going to make your head explode, if your bio filtration is keeping ammonia levels at a consistent 0ppm you're golden. That's it, headache over!

And as long as you're doing regular water changes to keep the resulting nitrate at sensible levels then all's good, you have a good bio system in place.
i get this, though there is some “rule of thumb” that seems to be present when thinking about a tanks stocking and future. for instance if i were to keep 7 rtcs in a 250g and for examples sake say that they don’t grow past 15 inches so they can actually all fit in there okay. their bioload would be far too much for a tank to handle no? i know its based off the gph and the feeding but there seems to be a general rule of thumb that people have when thinking about whether or not a tank is overstocked or not. like rays vs a bichir, many would argue that rays produce a much larger bioload than bichirs but is it due to them feeding the rays more or is it some biological process i’m unaware of.
 

shern

Plecostomus
MFK Member
Oct 17, 2023
253
125
51
Agree with esoxlucius, once the tank is cycled,, the only way to judgeis to test for ammonia and nitrite.
If there is enough media, before and after after a water change, tests will be negatice,
if there is a trace of ammonia, after a wa6ter change it may be due to the addition of chloramines (but only a trace, abd soon ofter, the media should take care of that trace).
The only measurable componant, is testing nitrate.
With an adequat schedule.....
If after a regular water change routine, nitrate concentration should no higher than 5 ppm.
If not, ...either that water change routine is not frequent enough, or not enoughwater is being changes.

You can supplement a lax routine by using heavily planted refugiums, tanks, or terrestrial growth.

When using onnly standard biomedia,
I determined thru a series of tests (that with my average stocking levels, for medium size, long lived cichlids)
my tanks needed every other day 30% to 40% water changes to maintain safe nitrate levels to prevent diseases like HITH, and hypoxia
.Exposure to Nitrate Increases Susceptibility to Hypoxia in ...The University of Chicago Press: Journalshttps://www.journals.uchicago.edu › doi

By employing heavily planted refugiuns, I could reduce those water changes by about 2/3rd per week..
View attachment 1553049View attachment 1553046View attachment 1553045

But each aquarium has its own set of needs, so a series of tests are needed to determine what those need sre.
If one keeps short lived air breathing Anabantids, or tetras that max out at only 3 years, chronic diseases may not be a concern.
But if the goal is to maintain long lived cichlids, such as oscars, Geophagines or severum that are prone to HITH (if kept in conditions such water pH or hardness)
not evolved to resist chronic pathogenic bacteria in), then nitrate reduction becomes much more of a cercern
is it mostly through trial and error then? if so it makes a bit more sense then. i’m sure there’s probably an actual equation but the WCs one does seem to have an effect on the overall parameter longevity. i made this thread because it’s confusing to me why people ask whether or not their tank is “overstocked”, is it the max size of the fish that people comment about or is it actually a bioload issue and lack of proper filtration that they worry about.
 

shern

Plecostomus
MFK Member
Oct 17, 2023
253
125
51
I am obsessed with water quality i always worry about my water if i see one of my fish do something i haven't seen before (flashing on a rock) i freak out.]
My only piece of mind is doing 3 large 80% WC as week
i only have a 125 with a FX6 and 2 XL sponge filter 1 fish is 8.5-9in the other is 10.5-11in i feed medium size pellets and very lightly 1X a day.
I would quit trying to be scientific and just do WC when ever you start going down that rabbit hole
that’s fair, trial and error probably my best bet here. this thread stems from me thinking about whether or not i could fit a floridan gar in my tank along with a pair of mini marbled motoros. the rays being especially sensitive would require pristine parameters. though i’m confident in my parameters i know that rays and gars have a large upload and i was unsure how that would strain my tank. i run double fx6s in the 250g and maintain 60-70% wc per week
 

esoxlucius

Balaclava Bot Butcher
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Dec 30, 2015
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If this thread was created to find out if any of us knew a calculation which could determine whether you could add your gar to your current ray tank, ensuring that your tank didn't crash in the process, then again I'll say there isn't a calculation. None of us know.

If I was you I'd simply add the fish and get a handle on your parameters before doing so. I wouldn't feed for the first couple of days either. Observe, and test your water daily.

You're looking for a slight rise in ammonia, though if your bio filtration is good, you may not see anything, it could be seamless, fingers crossed.

If things are fine after a couple of days I'd then feed lightly, still keeping tabs on parameters. If you're lucky you may be able to add this new fish and see absolutely no changes at all in parameters.

If you do see ammonia in the first couple of days of adding the fish, then you'll have to wait for the BB colony to increase and take up the slack, maybe doing a water change too.

I'd much rather take this "hands on" practical approach to adding the fish, rather than looking for some kind of none existent complex algorithm to tell me if it's safe or not!
 

troublesum

Dovii
MFK Member
Dec 28, 2007
559
474
102
Astoria, NY
that’s fair, trial and error probably my best bet here. this thread stems from me thinking about whether or not i could fit a floridan gar in my tank along with a pair of mini marbled motoros. the rays being especially sensitive would require pristine parameters. though i’m confident in my parameters i know that rays and gars have a large upload and i was unsure how that would strain my tank. i run double fx6s in the 250g and maintain 60-70% wc per week
I'm sorry not to sound harsh here but if you really have to think about adding the Floridan Gar then you probably shouldn't
Maybe its just me but it sounds like you want us to validate you adding the Gar
 
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