Self-Sustaining Tank

[Curiosity101]

I'm gonna be difficult. In a tank that receives no water changes, the issue with loss of buffing capacity (kH/GH) has to do with the nitrogen cycle. The end product nitrate can form HNO3(nitric acid) which is what causes that loss in pH. As you let a tank go without waterchanges more and more nitrate is produced, which reaches a equilibrium of NO3- and HNO3 depending on other factors in the water. Now as more HNO3 is produced it eats away at the KH/GH or the bases in the water that make up the buffering capacity. A tank will continue to do this till the buffering capacity is greatly diminished, then your pH will crash because HNO3 as an acid is still being produced but the tank has ran out of the molecules that normally react with it. This is a pH crash also know as old tank syndrome. Now there are two ways to try to avoid this. Plants take in nitrates and reducing NO3- effects the equilibrium and also reduces HNO3. They also consume NH3+ preventing NO3- from forming. The issue is that plants will also take a toll on water hardness factors Mg+2 and Ca+2. If you have really hard water with high KH a tank will be stable for a long time. If you are aware and pay attention to the buffering capacity of your water, you could just throw a tums tablet in when it gets low.

You aren't being difficult... you're saying exactly what everyone else had said...

 

[roadmaster]

Agree with all of the above. If one has water with any buffering capacity,, then topping off the tank (evapoaration) with this water ,can prevent water from becoming too acidic and fewer water changes pose no problems assuming plant mass is in proportion to fish load.
Others use GH booster, or create a substrate with a layer, or sprinkling, of Dolomite or crushed coral to help maintain stable water chemistry for longer periods.
From what I have read thus far on a couple of the planted tank forums, Most don't have planted tanks set up long enough to witness long term effects of any particular method of growing plant's with few exception's. They are frequently trying new aquascapes and the number's running low tech,Non CO2 tank's are few.

 

[roadmaster]

Am currently running a heavily planted,Non CO2,low tech, low light ,80 gallon tank with approx, 45 to 50 fish. Tank was set in july of this year and has received two 25 percent water changes due largely to re-arranging,and adding some new plant's.
Tank is dosed with EI method once every couple weeks mostly Nitrogen and pottasium.
The waste created by the fish and foods offered feed the plant's but there's no getting around cleaning the filter in my view/expierience.
For reference see.. (Tom Barr's Non CO2 method and planted aquarium)

^^ My old 33 gal stocked with 13 rummynose, 2 bolivian rams, 7 kuhli loach and 2 honey gouramis barely registered a nitrate reading at any point due to the fact the large amount of plants counter acted any that was made.

This still however, in my opinion, did not justify me not changing water as I pretty much asumed there would be more going on in the tank than just the nitrogen cycle. I could see there would be no issue with me not changing the water due to nitrates... but who knows what else is building up that we don't/can't test for.

Thats why I said earlier that although methods exist for keeping tanks in a maintenance free (ish) way exist... until I see some real results where people have been doing it and are seemingly having just as much breeding success and where the fish are definitely all growing and living to their full potential... I can't just say 'yeah just stop doing water changes... so long as you have plants it'll be fine...'

Of course you are right. For one to be able to suggest fewer water changes are possible,one should be willing to try the low tech ,low maint,NonCO2 method which should also require considerable research as to why and how it works along with that which will prevent/Hamper it from working
Many thing's to consider and possibly not suited for everyone depending on willingness to research all aspects of the low tech low maint tanks,and.... willingness to try.

 

[Curiosity101]

willingness to research all aspects

^^
This is the reason I never skipped water changes.

Yes we know about NO3 toxicity at high levels.
Yes we know about NH3 and NO2 toxicity at low levels.
We know how the buffering capacity can be altered without frequent water changes.

but what dont we know...Maybe we've covered all the bases, but maybe we haven't. And personally I find it hard to believe that the above is likely to be the only factors... I'm totally open to it and will read about people who have done it to see what results they've had. But I've not seen many long term results, and so it'll certainly not be a method I'm switching too any time soon.

 

[pinkspider]

I'm going to post about my experience, although as already discussed at length above I wouldn't recommend it.

My husband has never kept fish before he met me, but he very quickly caught "the bug" and we bought an ex-display Cleair 300l setup and Fluval external for him.

I gave him guidance where he needed it, but largely let him get on with it by himself as he'd read up on every aspect before he undertook the challenge.

We plumped for a sand substrate and populated the tank with some Java Ferns and Moss, lots of Valis and various other plants that caught his eye.

The external was set up from the beginning and there was also an internal trickle filter that we used for about a week before turning off the powerhead.

We cycled the tank for only a very short period of time (a big no-no, I know) and used Cycle for about 2 weeks daily.

The first fish (5 Green Tiger Barbs) were added after a week and flourished, and over the next month we added more and more. Including: Denison Barbs, Glass Cats, a Kissing Gourami, Clown Loach, Corys and various Rasboras and Tetras.

We didn't loose a single fish in the first 2 months of the tanks life, and after about 3 months we remembered we probably should clean out the external filter as the flow was down to a trickle. We did so, and another 6 months passed and more fish were added and we forgot about the filter.

Out of sheer laziness and the notion that the tank was supporting itself (we still hadn't lost a fish) we turned the external filter off and thought "Well, if things go down hill - we'll just get ourselves into gear and sort it out" - an awful mentality, I know.

Well, a year later and we haven't turned on the filteration again since. We're also yet to do a water change, and have topped the tank up by 1 inch, once.

We do have an airstone, mind you - as I think it looks pretty.

We have only lost one fish - and that was the other day, when a Bumblebee Catfish (that we didn't even know we had ) ate an old Neon.

We have over 200 fish in there, and a high percentage of these are over 5inch now.

We aren't counting our chickens though, we have just bought a 6 foot tank which we are currently setting up to house the larger fish (Denisons, Clown Loach etc), as it's obviously not fair to keep a tank overstocked.

Anyway, like I say - this is just my experience, and chances are we've just been VERY lucky or got away with being plain stupid.

This is the tank by the way:

Alys

 

[ian]

wow, 200 fish in a 300ltr is quite a lot of fish, from my view as well, i can see a common plec, kissing gourami, albino shark. Don't take this the wrong way, but i can see trouble in that tank.

 

[pinkspider]

wow, 200 fish in a 300ltr is quite a lot of fish, from my view as well, i can see a common plec, kissing gourami, albino shark. Don't take this the wrong way, but i can see trouble in that tank.

200 fish is a lot of fish, especially in a 300ltr tank - and given some of the varities we have in there (there isn't an albino shark though..that I know of!! and we don't have a common Plec - only 2 Ancistrus, 1 Golden Ancistrus and 2 Bristlenose) I am amazed that in it's nearly 2 year life that we haven't had problems.

Like I say, it's probably blind madness that's kept the tank going..we've never had a single problem with it and all the fish are thriving.

But again, like I mentioned in my first post - we are setting up a 6 foot tank to house the larger fish, as it's not fair to have them in there for much longer.

I've always worked along the principle of: If it ain't broke, don't fix it.

My fish are all healthy, many are prolific breeders, and we've never had any water quality issues or any illness.

We have a variety of other thanks, all of which operate with the useage of filteration but none ever have water changes and have full water tests carried out on them once a week.

Alys

EDIT: I am the woman, after all, that is shunned by almost everyone in the Oscar community because I have never done a water change on a tank that's been established for over 6 years, and has successfully spawned many a baby Oscar..oh, and the fact that I had two Golden Gouramis living with 4 juvinille Red Tiger Oscars and a 12" Albino Oscar

 

[dayzofspeed]

my answer to the original post would be............. dont bother, if you wanted an aquarium you would've bought one instead of just taking a freebie cos it was offered, or if you must have the tank just put plastic plants in it or sea monkeys