# Water Change or Top-Off [Mature Aquarium]



## OneLastDecree (Nov 13, 2012)

So, I have a 20G Long Main Tank plumbed into a 20G Long Sump. 
It has been running for almost 2 years?

My water parameters are the following:
Ammonia: 0 PPM
Nitrite: 0 PPM
Nitrate: 0 PPM

pH: 6.5-7.0
Temp: 80 F

Livestock are the following:
pair of Apisto Cockatuoides.

Flora:
5 stems of Amazon Swords. (Probably more now with them branching off).
50 Frogbit.

Now, when i conduct a WC; I only top-off.
I do not remove any water or detritus or left over food.
I actually over feed on purpose. 
So the food will break down for the benefit of future fry, microorganisms, bio cycle, etc. 
Apisto's regulate intake; so it is fine. 
i even let my dying off Indian Almond Leaves to just disintegrate in the water column and don't remove. Same applied to the swords when a part of them brown out.
No pruning or anything is done to the tank except feed ona daily basis. 

Now, my question is. 
Should I still be removing water when conducting a water change or not?
Am I okay just topping off every two weeks. 
Sometimes a month. 

I have been topping off for about 6 months now.
Never removed water. 

Anytime I actually went nuts and deviated from the plan was when I topped off with equal parts Distilled water and equal parts tap.
Just to induce breeding by mimicking the Amazon Rain Forest seasonal movements.


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## OneLastDecree (Nov 13, 2012)

You can see the mulm and the condition of the bed in my aquarium in the following video.
It is very clean, considering.


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## pyrrolin (Jan 11, 2012)

I used to have the view of just topping off if nitrates were not going up but I changed my view a few months ago.

In your case it is an even easier decision. Doing a wc won't lower your nitrates too much because there are none. Have you ever tested phosphates? higher phosphates can cause algae.

Now to my new view. doing a water change helps replenish the minerals for the plants. There are lots of minerals in tap water that plants need and unless you are dosing every mineral found in tap water, you will be missing some of these minerals. Also, if you have anything that colours the water, dirt, driftwood and such, it also does a lot to clear up the water and make it clearer which for many looks better but also means better light penetration for the plants.

The days I do a large water change on my main tank, I get lots of pearling so I think a large wc also helps add some co2.

You don't have to clean the bottom, just remove water if you want.


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## solarz (Aug 31, 2010)

As your nitrates are 0ppm, you could probably get away with not doing water changes for a while. Still, I would not forgo water changes completely. Even a small one from time to time helps reset your tank's water parameters. By only topping off, you will eventually end up raising your tank's hardness by quite a bit.


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## solarz (Aug 31, 2010)

pyrrolin said:


> The days I do a large water change on my main tank, I get lots of pearling so I think a large wc also helps add some co2.


Keep in mind that there is a lot of gas dissolved in tap water. It's not necessarily pearling, it could just be bubbles.


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## OneLastDecree (Nov 13, 2012)

Hey Solarz!
Long time. 
I still have your media you gave me in one of my 20G. 
Haha. 

Anyways, back to topic. 
I understand where everyone is coming from.
Thank you for the insight.
But from all my readings, I have a question I can't find the answer to.

Now, I have a low-tech plant.
5 or more Swords, and tonnes of Frogbits.

I know the flora take time to adjust to new water paramaters and etc.
Especcially in the low-tech setups.

My logic is, if you don't change the water params and just top off like a gallon every month. Wouldnt that be more beneficial to the plants; rather than, doing an actual PWC by removing say 25% of water and refilling back with 30% water to consider change in water evaporation. Keepign in mind that the water params will stay cosntant and consistent. 

The reason I am asking is because I finally won the battle against hair algae and other strains of algae like blue green in the first place. 
My algae is very minimal and it actually looks nice. 
I believe I won the fight against algae because of reduced water changes and letting the plants adjust to the water paramaters so they can eat all the Nitrates from the water column.
obviously other factors are involved like manually removing and reduced lighting. 
But after i stopped doing Water changes to keep the water params steady for my flora, it seemed it did better in removing my algae. 
Therefore, the flora were more capable of competing with my algae for nutrients.
In turn the algae died off. 

What do you guys think of my little perspective.
I'm just worried that increased water changes will change the direction of the war on algae. 
Oh, during the time of not conducting any water changes, my swords grew 5 inches in a month. That is without removing any dead portion of leaves. 
Just insane.

i might have to prune them.


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## pyrrolin (Jan 11, 2012)

never heard of wc causing algae, wc help remove stuff that cause algae. water parameters shouldn't change with a wc unless you lots of something in the tank that changes ph and stuff like driftwood or peat or something.

and about the pearling, it is pearling when I do a wc, you can see the tiny bubbles coming off some plants, not just little bubbles floating around in the tank.


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## OneLastDecree (Nov 13, 2012)

I was talking in more focus to the C02 level.
Breaking the water surface with a PWC will swing the CO2 levels already stable?
Therefore the plants will have to waste more energy in adjusting to the fluctuated C02 level before taking up the nutrients in the water column.

If that makes sense. 

On another note, I thought pearling was when the plants excreted the 'bubbles' on its own.
I think Solarz is saying that it might be the bubbles from the water change that gets caught on the plants and/or decor.

Anyways, thanks for the clarity.


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## pyrrolin (Jan 11, 2012)

there are those bubbles, but there is also pearling when I do a large wc, streams of tiny bubbles coming off some plants for hours.

if you aren't running a co2 system, I believe a wc adds some co2 but I could be wrong. My plants love water changes.


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## solarz (Aug 31, 2010)

OneLastDecree said:


> Hey Solarz!
> Long time.
> I still have your media you gave me in one of my 20G.
> Haha.
> ...


Keep in mind that water parameter involves more than just nitrates. There is also hardness to consider. Unless you top off with distilled water, your water hardness will increase with each top off.

Like I said, with a mature planted tank, you can probably get away with only top-offs for quite a while. I've gone months without WC on my planted tanks. However, when I do get around to doing one, I usually do at least 30%.

Simply put, water changes keep your tank water parameters close to that of your tap water.



pyrrolin said:


> there are those bubbles, but there is also pearling when I do a large wc, streams of tiny bubbles coming off some plants for hours.
> 
> if you aren't running a co2 system, I believe a wc adds some co2 but I could be wrong. My plants love water changes.


Tap water does have a lot of CO2 dissolved in it. This can be verified by checking the pH of the water straight out of the tap, and then checking it again after leaving it sitting overnight. Toronto tap water, out of the tap, has a pH of ~7.5. After leaving it overnight, the water pH rises to ~8.0.


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