What, actually, is Stocking Levels?

[Bradders]

Ok, then. Well, Aquarium Science got a lot of fine information and advice if your running a plant-less or near plant-less tank... They are putting an overt large amount of attention on external filtration which matters far less in a moderately to densely planted tank. Flow and nutrient distribution matters a lot of course in a planted tank, external bio filtration not so much.

......which is interesting. The filter media aspects seem to have some measure of effectiveness - albeit caveated with some degree of approximation. However, how does one calculate the effectiveness of plants and the part they play within aquarium filtration? That part seems hard to quantify - unless I am missing something?

 

[fredi]

Experience tells me that a 10” Oscar, requires many times (much, much more than double), the filtration capacity of 10 x1” tetras or guppies

I think that is what the chart is saying. In the table, you can see (based on the approximations and looking at filter-based filtration only) that you can keep 168 x 1-inch fish due to the metabolic weight and waste output. But as you move toward a 6-inch fish, you can pretty much only keep 1 with the same filter.

Seems like they got bored at 6”
Guessing they used body mass, and ignored behaviour etc

 

[Bradders]

Seems like they got bored at 6”
Guessing they used body mass, and ignored behaviour etc

Sorry, the 6 inch is my copy cut and past rounding error! Basically, from 6 it's a 'no'.

And yes, all of the data comes with a gross approximation due to size and type of fish.

 

[Tim Harrison]

I think for many scapers, at least, plants come first and the fish are chosen to compliment the scape. It doesn't mean they are any less important in terms of husbandry though. For me less is definitely more. So overstocking or coming anywhere near is never really a problem.

But like most of these things they require a deal of common sense and experience to get right. However, I think we all have an idea of what's excessive, and stay well below that threshold. It's probably the safest approach, especially since this thread has highlighted there appear to be no hard and fast rules, just vague guidelines, and every tank is different.

Lots of plants and a few fish...

 

[Bradders]

Is that your aquarium @Tim Harrison ?

 

[Tim Harrison]

Is that your aquarium @Tim Harrison ?

Yes it’s one of my scapes from a few years back. No longer running.

NatureScape - The End

Rule of 3ths? Look at it 1, 2, and 3, what do you see :nailbiting: :thumbup::clap: Haha, thanks Marcel :) So I had a break and went back to it and added some more rocks,,,

www.ukaps.org

 

[Bradders]

Very nice scape indeed! Looked lovely.

 

[dw1305]

Hi all,

......which is interesting. The filter media aspects seem to have some measure of effectiveness - albeit caveated with some degree of approximation...

You are still in "apples and oranges" territory, none of these estimations are comparable, without a measure of the amount of dissolved oxygen in the system and, most importantly, it's rate of replenishment. You can process huge bioloads, if you can continually refresh the level of dissolved oxygen.

This is why they culture Salmon etc in raceways, the extra running costs are offset by the higher stocking density.

...... However, how does one calculate the effectiveness of plants and the part they play within aquarium filtration? That part seems hard to quantify - unless I am missing something?

You would need to the scientific literature on phytoremediation or aquaponics, but basically you get a lot more biological filtration capacity ("you can process larger bioloads") in plant / microbe biofiltration when all compared to "microbe only".

As well as the oxygen production from photosynthesis you also get the CO2 sequestration and that also allows you to increase stocking density.

I'll add in some links when I've got access to a PC.

Cheers Darrel

 

[Bradders]

You would need to the scientific literature on phytoremediation or aquaponics, but basically you get a lot more biological filtration capacity ("you can process larger bioloads") in plant / microbe biofiltration when all compared to "microbe only".
As well as the oxygen production from photosynthesis you also get the CO2 sequestration and that also allows you to increase stocking density.

And I think that is where my head is. How do you even come close to measuring that? Can people with heavily planted aquariums simply dial down their filtration? How would they know?

Maybe I am trying to measure the unmeasurable! But when you hear that aquaponics gives you a lot more biological filtration you kind of want to ask 'how much, and with how many plants'. 😆

 

[MichaelJ]

And I think that is where my head is. How do you even come close to measuring that? Can people with heavily planted aquariums simply dial down their filtration? How would they know?

Maybe I am trying to measure the unmeasurable!

As hobbyist we generally do not have reliable means to quantify the effectiveness other than using our eyes (waste buildup, algae, unhappy plants and fish etc.). There are ways to get at least a sense of the situation however; One approach is to measure Oxidation-reduction potential (ORP) - I did for a while and occasionally still do a measurement at the substrate level. ORP especially if measured along side other parameters such as Dissolved Oxygen can help determine a biological systems ability to break down waste. But it's arguably very hard to interpret the results from an ORP measurement by itself.

For a moderately to densely planted aquarium the active bio filtration from plants and substrate (unless you are deploying a massive external filtration system) far out weights the importance of external bio filtration - but of course everything counts - many prefer the belt and suspenders approach.

But when you hear that aquaponics gives you a lot more biological filtration you kind of want to ask 'how much, and with how many plants'. 😆

It depends... more is generally better

Cheers,
Michael

 

[fredi]

Maybe I am trying to measure the unmeasurable! But when you hear that aquaponics gives you a lot more biological filtration you kind of want to ask 'how much, and with how many plants'. 😆

I think that there are too many variables
It’s not just the nitrification process, there are many organics to be dealt with
The type and size of filter, filter media, configuration of filter media, flow through filter media, flow through tank, plant type, number/mass of plants per unit volume, any additional rock, wood, the list appears endless (to me)
I gave up optimising my filters, when I found the cheapest solution that worked for me👍

As hobbyist we generally do not have reliable means to quantify the effectiveness other than using our eyes (waste buildup, algae, unhappy plants and fish etc.). There are ways to get at least a sense of the situation however; One approach is to measure Oxidation-reduction potential (ORP) - I did myself for a while and occasionally still do a measurement at the substrate level. ORP especially if measured along side other parameters such as Dissolved Oxygen can help determine a biological systems ability to break down waste. But it's arguably very hard to interpret the results from an ORP measurement by itself.

For a moderately to densely planted aquarium the active bio filtration from plants and substrate (unless you are deploying a massive external filtration system) far out weights the importance of external bio filtration - but of course everything counts - many prefer the belt and suspenders approach.



It depends... more is generally better

Cheers,
Michael

I measure orp, it’s settled now, it has taken months to reach where it is
Orp drops 30 odd points at each and every feeding, I switch filters off for 7mins, reduce flow from mp40’s from 25% of max to 6%
It takes 2 hrs to return to previous figure (510 ish)