Water Change Frequency - Some open thoughts

[Digimon]

I have been dosing NPK (Dr Mallick's) and traces (Easylife Profito) using Chuck's Calculator as a start-off for the dosage, and slowly adjust the dosage using the EI's method (although not fully grasped this method yet).

Water change is about 50 - 60% weekly.

Now, I have been thinking, we do water change to prevent excess nutrients and ammonia (those that the bacteria could not break down in time) build-up. I read many threads indicating that excess nutrients do not caused algae issues. So if we do not overfeed & create too much ammonia such that the bacteria could not break down in time, is water change necessary?

But come to think of it, if all the while we are dosing in excess, there may be 1 day my critters are living in my pre-mixed solution of NPK instead of water.

So we can't really eliminate water change but maybe reduce the frequency?
Once a month with 70% water change? Once per 2 months?

Pls dun misunderstood, I'm not trying to eliminate the commitment part of the hobby. I believe in having commitment in everything we do. Just voicing out my thoughts. Maybe can have a more stabilised tank condition or reduce some of my PUB bills?

What would be the pros & cons or causes & effects?

[PeterGwee]

Now, I have been thinking, we do water change to prevent excess nutrients and ammonia (those that the bacteria could not break down in time) build-up. I read many threads indicating that excess nutrients do not caused algae issues. So if we do not overfeed & create too much ammonia such that the bacteria could not break down in time, is water change necessary?

Bacteria do not break down the inorganic NPK but the ammonia (Nitrogen cycle).
If the uptake by plants always equal to the amount you dose via inorganic fraction along with recycled organic forms, then you do not need to change the water. (Are you so lucky to begin with?...Bacteria does not take in N,P,K for your info.). If you want to do less water changes, go non-CO2 and reduce the light and critter loading. Each method does have its tradeoffs. You cannot get away from it.

Regards
Peter Gwee

[elmike]

Who says it's NOT POSSIBLE to get away with water change?

If you do plants-only tank, then you don't need water change, no?

[Phillipians]

actually i believe the need to do water change only helps if you are dosing at exactly the optimum level where excess nutrients might build up example Cu, which might be harmful, however if your tank is matured water change can be reduced to once in 3 weeks or 1 mth. My tank is about 9 mths to a year old, and i do water change at 3 to 4 weeks, once. But i dont dose like daily my fert regime is as follows:

twice a week
.5ml LGM (or 10 drops)
Kno3 and mgso4 half teaspoon
a little of kh2po4

and in the middle of the week i also add 4 - 5 drops extra LGM.

mine is 2 x 1 x 1.5 72W 1BPS co2

So i think mature tanks are no prob, make sure once a month should be sufficient

[Digimon]

I currently have a 1 feet cube tank that is on non-CO2 setup and a recently converted 2 feet to 3 feet tank that is on CO2 setup.

With the non-CO2 tank, water change is about 6 months once.
With the CO2 tank, water change is at least 50%, once a week.
Both tanks are going to 2 years old.

Just curious that it seems there is always the mentioning of excess nutirents do not cause algae problem. So when we change water, we are preventing
1) excess nutrients build-up or over-dosing, right?
2) ammonia build-up due to bacteria unable to break down in time, right?

So if excess nutrients do not cause algae issues, we can let it be in the tank slightly longer? And if we control our feeding, we can prevent ammonia build-up to a certain extend, right? Thus this water change question pop up in my head.

I understand that bacteria do not break down the NPK. And I am not aiming at achieving an ideal dosing regime where intake equals amount dosed as there won't be such a scenerio. I aim at providing a non-limiting dosing for the plants. But do we need to reset the level every week if the excess do not cause any issues?

[|squee|]

If I'm not wrong, this is to prevent nitrate buildup that's harmful for fishes. Also, the fact that excess nutrients don't cause algae is made from reference to the EI. Other dosing regimes (commercial ones esp) might have a different "working plan".

And yes, you can let it be in the tank slightly longer (talking about EI here), as long as you're confident that plants are absorbing in whatever you put in at a good enough rate that it doesnt build up to harmful levels for livestock.

Note that the EI did state that you need not adhere to the 50% weekly water changes. (I may be wrong, the EI has been revised) In addition the EI does state a range of ideal values. As to why this is so perhaps Tom Barr can explain when he sees this. There's still much we haven't learnt.

Also, in my own wild belief, those ions (NO3 and PO4) will not remain as such for long... they might react with other stuff so plants can't get to them. Water changes also take away the possiblity of alleopathic effects (Diana Walstad mentions this in her book, Ecology of the Planted Aquarium), but I'm not too sure if alleopathy has any real effect at all. Plus, nothing beats fresh water. It's the same idea as air... we don't like stale old air recycled again and again by an air-conditioner do we?

[Digimon]

I fully agree with you, |squee| & Peter, on the need for water change on high maint tank.

Personally, I also feels that the fishes and plants "sparkles" after water change. They look happier and healthier, to me.

Basically, I just want to find out more on the need of doing water change, other than the 2 points I brought up.
Secondly, to see if schedule forbids, how long could I delay the water change.

Now I have a clearer picture. Will stick to my weekly routine, at worst, 2 weeks is the longest I will delay.

By the way, I thought nitrates are harmless to the fishes. Nitrites are the toxic ones, isn't it?

Thanks for everybody's advice.

[|squee|]

Nitrites are toxic in lesser amounts, like ammonia if I'm not wrong. You can go up to higher levels of nitrate before fish start to have problems (100ppm or more if I'm not wrong again)

[tango]

Just to share,

I have not performed water-change for more than a year for my 3 ft tank (high light x 6hrs, 3bps CO2, and 26 degree average) and I dose with Dr mallick LGA (half cap) and Micro (4 drops) twice a week; I feed my tetra and mosquito rasb once every alternate day.

The only problem I faced is shrimps (cherry or malayan) cannot make it in my tank. Other than that, all are OK, no algae bloom, just that the water is a bit yellowish due to the dw.

tango

[elmike]

Just to share,

I have not performed water-change for more than a year for my 3 ft tank .

Oh? Got fish some more?
I'm interested!
How rarely then do you wash/ change your filter media? I know they get clog up after 3 mths and that this will affect water circulation/ filtration rate, which diminishes the size of your bacterial colony, which in turn, affects water cleansing.

[Digimon]

Nitrites are toxic in lesser amounts, like ammonia if I'm not wrong. You can go up to higher levels of nitrate before fish start to have problems (100ppm or more if I'm not wrong again)

Ok, got it. Thanks a lot guys.

[tango]

Oh? Got fish some more?
I'm interested!
How rarely then do you wash/ change your filter media? I know they get clog up after 3 mths and that this will affect water circulation/ filtration rate, which diminishes the size of your bacterial colony, which in turn, affects water cleansing.

For my filter media, the last time I washed is two years ago. I also not sure why this works for me, when everyone is recommending water change on a monthly basis.

tango

[Plantbrain]

Who says it's NOT POSSIBLE to get away with water change?

If you do plants-only tank, then you don't need water change, no?

Sure, but then you need to test and dose accordingly.
That, cost, effort to test various paramaters and the guess work associated with it is often much too much for many folks.

I can easily go 3-4 weeks without a water change, but every scaper worth their salt does many large water changes, Luis N, Oliver, folks here in CA, Amano etc.

Sometimes 2x a week to really keep on top of things.
You can get away with fewer and have things look pretty decent also.

You can also simply install an auto water changers and solenoid/float switch valve for refill.

I have a hard plumbed drain and fill installed on larger tanks, I simple turn on a valve to drain, turn another to refill.

Simple.

Regards,
Tom Barr

[StanChung]

hi tom,

that's ideal...we're quite lucky here the water pressure is ok. pity those guys that take 1.5 hrs to change water...

[Plantbrain]

I read many threads indicating that excess nutrients do not caused algae issues. So if we do not overfeed & create too much ammonia such that the bacteria could not break down in time, is water change necessary?

What would be the pros & cons or causes & effects?

Well, the nutrients will go very high and kill the fish.
So there is an upper limit, one I've looked into more than most.
Water changes allow you to maintain a nice stable ablance without test kits and guessing what needs to be added.
It also allows up to remove mulm/detritus/dirt that builds up in the tank.

Non CO2 tanks achieve the balance you seek nicely.
Not much effort once set up for the fish nor the plants.

Thing is, folks always want to cram more and more into the tank, want more plants/more growth etc.

If not, go non CO2.

Regards,
Tom Barr

[Plantbrain]

hi tom,

that's ideal...we're quite lucky here the water pressure is ok. pity those guys that take 1.5 hrs to change water...

That's what simple automatic timer based water changers are for.

Bubba sez:
The lazy man is often the smartest.

But that, or a python style water changers makes things so much eaiser.
My largest systems all have hard plumbed drain and fill, all I do, turn a valve to drain, turn another to fill.
Nothing else.

While the tank drains, I clean and prune and as it fills I add ferts/refill reserviors etc.

It's not an issue at all, the pruning/cleaning is easier when the water level is down also.

Auto water changers can change the tank 2x a week and then you dose 2-3 x a week, then it's really easy, add a dosing pump or two, then you are really lazy.

Regards,
Tom Barr

[Digimon]

Well, the nutrients will go very high and kill the fish.
So there is an upper limit, one I've looked into more than most.
Water changes allow you to maintain a nice stable ablance without test kits and guessing what needs to be added.
It also allows up to remove mulm/detritus/dirt that builds up in the tank.

Non CO2 tanks achieve the balance you seek nicely.
Not much effort once set up for the fish nor the plants.

Thing is, folks always want to cram more and more into the tank, want more plants/more growth etc.

If not, go non CO2.

Regards,
Tom Barr

Got it. Actually, I have tried up to 3 weeks before doing a water change. With my current dosing, no casualties observed. I had used this guide as my upper limit. I still do water change weekly to maintain things at the ideal level.

Thanks a lot for all the knowledge and advices.