How Big Should A Tank Be To Be Self-Sustaining?

[Zante]

Let me qualify what I mean by self-sustaining: you'd still have to feed, maybe filter, but you'd reach a balance where you wouldn't make water changes anymore.

I was thinking of something fairly low tech, that would house a shoal of discus, a large school of tetras and a herd of corys. Very understocked I'm guessing, and thickly planted.

NOTE: I'm not planning anything of the sort, but I had a bit of free time at work and my mind started wandering a bit in this direction. I just thought I'd start an interesting conversation.

 

[brian1]

Can't wait for the answer to that one.........would be greeeat.......

 

[angelfishguy]

I dont think it will be possible with discus, have a read of bigtom's bucket of mud in the planted journals. He had it self sustaining.

 

[fluttermoth]

Isn't this what's called the 'Walstead' method? Try Googling that, Zante, you might pull up something useful.

 

[Zante]

Isn't this what's called the 'Walstead' method? Try Googling that, Zante, you might pull up something useful.

I didn't know about the Walstead method. Thank you fluttermoth, it was an interesting read.
I think I will get the book.

Anyone try this (or other) methods to create a balanced environment? Tank sizes? Stocking? Results?

 

[Electric Warrior]

Keeping discus in a NPT where you are not doing frequent WC's and not doing bio filtration sounds like bad news to me? Someone correct me if I am wrong.

 

[MBOU]

IMO "never" in a normal tank withought specialist filtration/equipment etc.

Even with plants to keep using up nitrates etc... there are a LOT of other nutrients/excess nitrates if plants die or dont use it and so on that i think.. 'never'.

If anything... with loads of plants.... bigger and more frequent waterchanges is recommended. With discus, frequent changes is a must, in the countries like Malaysia where they are bred, they get 100% changes daily... literally... bottom drains on tanks mean discus flap about and then tanks are auto topped up, not a bad thing in their sense seeing as their tap water might look brown (in what i've seen) but is far better quality that ours in the UK.

 

[Zante]

Keeping discus in a NPT where you are not doing frequent WC's and not doing bio filtration sounds like bad news to me? Someone correct me if I am wrong.

If by NPT you mean Non Planted Tank then no, quite the opposite, I'm talking understocked with lots of plants

IMO "never" in a normal tank withought specialist filtration/equipment etc.

Well.... I'm not talking of a normal tank am I?

Even with plants to keep using up nitrates etc... there are a LOT of other nutrients/excess nitrates if plants die or dont use it and so on that i think.. 'never'.

If anything... with loads of plants.... bigger and more frequent waterchanges is recommended. With discus, frequent changes is a must, in the countries like Malaysia where they are bred, they get 100% changes daily... literally... bottom drains on tanks mean discus flap about and then tanks are auto topped up, not a bad thing in their sense seeing as their tap water might look brown (in what i've seen) but is far better quality that ours in the UK.

Uhm... MORE water changes with live plants?
Are you SURE?

That goes against what I know. Anyone confirm this?

 

[MBOU]

You could, it wouldnt look clear or clean though plants change the colour of water, on my heavy planted tanks, no matter how clear (50% weekly and 30% weekly plus5W UV on a 300L tank) the water is, if i siphon it out into a white bucket, its bright green water!

Trouble is... what do you do with rotting plant matter? Even if you didnt water change, you'd be cleaning filter at least once or twice a week (by which point is a waterchange so hard!?) to get rid of rotting plant matter!

Without water changes, you might struggle to get the exactl balance between plants/algae just right and even at just right... if you feed plants.. you feed algae = you need to clean!

Without taking water out... you get more and more and more nitrates/phosphates/silicates and metals etc. Plants can only use so much of these elements before these elements start feeding algae too.

It is possible... its just not really worth doing if you want tank to look clean and pretty!

I run my planted tanks on a no feed/no CO2 but slightly over stocked and pretty over fed basis. I do two big water changes a week which is no problem as its at work and the filter every other week with its UV. Fish are over stocked in numbers technically but being so heavily planted, you rarely see the 25- 30 cardinal tetras (i hate cardinals... 35 added but thankfully someone added adult pair of angels whilst i was away) down to 25 or less now...

 

[Electric Warrior]

Keeping discus in a NPT where you are not doing frequent WC's and not doing bio filtration sounds like bad news to me? Someone correct me if I am wrong.

If by NPT you mean Non Planted Tank then no, quite the opposite, I'm talking understocked with lots of plants

No, no NPT meaning naturally planted tank.

 

[MBOU]

Sorry, i'm not being clear tonight (PITA trying to reply to interesting posts when i already got bored and drank most of a bottle of wine lol).

More water changes to keep it clean and clear. If you dont care that the water is a green colour then hey... nm.

Look at all the beautiful aquascape tanks... look great. Most arent st up more than about 24 hours tops though!

 

[Zante]

Well... I'm not thinking of a tankful of plants, where you can't see fish, but a well planted tank, very understocked, and apparently, according to the Walstead method that fluttermoth mentioned, it would be self-sustaining in the sense that I meant.

Obviously to stock a population I mentioned in my example it would have to be seriously big, possibly in the order of 400 gallons or more.

TBH, i don't know much about this kind of low tech tanks, and neither I have the inclination to try one, not yet at least. I just think it is an interesting subject and wanted to start a discussion about it, possibly with people who'd tried this or similar methods.

 

[Electric Warrior]

I understand the method and the concept behind it, it's just the discus that I am wondering about? I am not in one of those camps that believes that discus are these incredibly super-delicate fish need bare bottom setups, or that will shrivel away if you put a drop of hard water in your tank, but I think it may be a bit iffy since they do need extremely high water quality, i.e.. clean water. Most discus on the market are usually tank bred in less than ideal "natural conditions," meaning that they are hardier than their wild caught cousins, but I don't know that if you want to grow out a group of juveniles, for example, that it would work very well?

 

[Zante]

I understand the method and the concept behind it, it's just the discus that I am wondering about? I am not in one of those camps that believes that discus are these incredibly super-delicate fish need bare bottom setups, or that will shrivel away if you put a drop of hard water in your tank, but I think it may be a bit iffy since they do need extremely high water quality, i.e.. clean water. Most discus on the market are usually tank bred in less than ideal "natural conditions," meaning that they are hardier than their wild caught cousins, but I don't know that if you want to grow out a group of juveniles, for example, that it would work very well?

Honestly I don't know.

The discus were just an example for a hypothetical stocking.
It could have been just as easily angels, loaches or gouramis.

 

[BigTom]

Emergent plants are key. Read my 'Bucket of Mud' journal. It can be done, in fact it's easy as long as your stocking is very light - no feeding, no filter, just water top ups. Perfectly clear water. But I never pushed it beyond very small fish - certainly wouldn't try it with anything large like discus without a truly massive tank.

No reason not to change water if you can, but it is possible.