How long to go without a water change?

[PattysAquatics]

So I have a heavily planted 75 gallon community tank. I haven’t done a water change in a month. I check the water parameters weekly with the Aquarium CoOp test strips ( which I love by the way) and am staying in the 10-20 ppm range for nitrates. I dose easy green weekly. My question is there a point I should do a water change even if the parameters are good? I used to have this tank stocked with bigger cichlids and had to do weekly water changes to keep the nitrates under control so this is new to me. 

[Daniel]

Your plants are doing most of the work. I think you can go for a very long time, maybe indefinitely without water changes. As long as the parameters are good, all you really need is a top off when needed.

[Patrick_G]

I’m interested in this question too. I’m going on three months with a new 75g and haven’t done a water change yet. I’m dosing Easy Green at the medium light level or slightly higher. @Daniel, is there a way I can test to make sure I’m not building up a excess of elements other than Nitrogen? 

[BF McUmber]

@Grizzly what does your heavily planted look like, do you have a picture? I'm planning out a new tank and am looking to eventually get to a place like where you are with he limited/no water changes. 

[PattysAquatics]

On 6/21/2021 at 7:27 PM, bwar said:

@Grizzly what does your heavily planted look like, do you have a picture? I'm planning out a new tank and am looking to eventually get to a place like where you are with he limited/no water changes. 

 

[BF McUmber]

Thank you for sharing 🙂 That gives me a nice starting reference density. 

[lefty o]

time to clean, when water parameters dictate, or it visually bothers you. ive let my 120 go so long before, i wouldnt even mention it here, because folks would shake their head.  if a tank is running good, and is in balance, they truly dont need frequent water changes.

[tonyjuliano]

On 6/21/2021 at 6:45 PM, Daniel said:

Your plants are doing most of the work. I think you can go for a very long time, maybe indefinitely without water changes. As long as the parameters are good, all you really need is a top off when needed.

This…

[tonyjuliano]

On 6/21/2021 at 8:12 PM, Patrick_G said:

is there a way I can test to make sure I’m not building up a excess of elements other than Nitrogen? 

Other than “the big three” (ammonia, nitrite, nitrate) what’s left to test for that could be harmful?

You would never have too much iron (unless you put in there, it reduces uber quickly).  Potassium?  No such thing as “too much” really.

Phosphorus in excess can cause algae, but won’t hurt your fish.

Edited June 22, 2021 by tonyjuliano

[Gideyon]

@tonyjuliano, I see on your signature you have two tanks with a slow moving plenum.  Have you managed to go a considerable amount of time without a water change in them? 

[Gideyon]

On 6/21/2021 at 6:42 PM, Grizzly said:

My question is there a point I should do a water change even if the parameters are good?

I'm new to the hobby, but my understanding is the nitrates determine when to change.  Not a schedule.  

I sometimes change even when the nitrates are low (never went above 10ppm).  But it's only to gravel vac. I don't have plants to feed off the waste in the gravel, so I an extensive vacuuming every few weeks to a month.  The water change is a byproduct of me trying to clean the gravel. 

 

But if you're planted, I don't think it's necessary. 

[tonyjuliano]

On 6/21/2021 at 10:37 PM, Gideyon said:

@tonyjuliano, I see on your signature you have two tanks with a slow moving plenum.  Have you managed to go a considerable amount of time without a water change in them? 

They aren’t fully up and running yet, currently waiting on the cycle to be fully established.  It’s a bit of an experiment.

I must say, however,  that these 2 tanks have been the quickest cycling (fishless, with no donation from an established tank) that I’ve ever seen.

Details, so far, here…

 

[Mmiller2001]

On 6/21/2021 at 6:12 PM, Patrick_G said:

I’m interested in this question too. I’m going on three months with a new 75g and haven’t done a water change yet. I’m dosing Easy Green at the medium light level or slightly higher. @Daniel, is there a way I can test to make sure I’m not building up a excess of elements other than Nitrogen? 

It's not specific, but a TDS pen will let you know if your having a buildup.

[BaRanchik]

If your tank is algae free then most likely that you don't have any excess of elements in there. If you had it you'd see different algae types (depending on which element is overdosed), but your tank looks clear to me.

The only thing I'd make sure is that you don't have a calcium deficiency, as I believe everything else is pretty much covered with Easy Green. You can tell there is a calcium deficiency if new leaves grow in weird shapes.

[ARMYVET]

On 6/21/2021 at 10:40 PM, Gideyon said:

I'm new to the hobby, but my understanding is the nitrates determine when to change.  Not a schedule.  

I sometimes change even when the nitrates are low (never went above 10ppm).  But it's only to gravel vac. I don't have plants to feed off the waste in the gravel, so I an extensive vacuuming every few weeks to a month.  The water change is a byproduct of me trying to clean the gravel. 

 

But if you're planted, I don't think it's necessary. 

On my original 90 gallon plant tank I used a magnum 350 cannister filter to do my gravel vac without having to change any water.  Just put the tube on the intake with fliter floss and vac the substrate...did that every 5-6 months just to remove excess... Worked very well and no water mess anywhere lol.  

[Patrick_G]

On 6/21/2021 at 11:28 PM, Mmiller2001 said:

It's not specific, but a TDS pen will let you know if your having a buildup.

Thanks, that makes sense. 

[Expectorating_Aubergine]

I say hold off on water changes until your test strips say so. I have tanks going on 3.5 years that I only do top off on. One of them is a tank with bichirs and rope fish. The only thing I ever worry about is ph.

[eatyourpeas]

I have heavily planted and overly filtrated tanks, so if I miss a water change I do not fret.

Having said that, someone had a tank crash from excess TDS when changing the water after a few years of not doing any. But that was years! 

I think observing the tank and critters is a good indicator of the health of the environment. 🙂

[Mmiller2001]

On 6/21/2021 at 4:42 PM, Grizzly said:

So I have a heavily planted 75 gallon community tank. I haven’t done a water change in a month. I check the water parameters weekly with the Aquarium CoOp test strips ( which I love by the way) and am staying in the 10-20 ppm range for nitrates. I dose easy green weekly. My question is there a point I should do a water change even if the parameters are good? I used to have this tank stocked with bigger cichlids and had to do weekly water changes to keep the nitrates under control so this is new to me. 

You should ask yourself, are Nitrates the sole determinate factor in fish keeping? I ask myself that a lot, and the answer is no. There's way more chemistry going on and I want to operate at peak performance. Tanks like this, don't go a week without a 50% water change (or greater). Are tank like this everyone's goal, probably not, but do they want it to be? I respectfully, would ask anyone, not changing water, to show pictures of there tanks. And they will almost never look like these tanks. Is it worth it to not change water, IMO, nope.

Ask any person keeping tanks like these, and water changes are 1000% mandatory. 

 

[Gideyon]

On 6/22/2021 at 5:49 PM, Mmiller2001 said:

Are tank like this everyone's goal, probably not, but do they want it to be?

Nope. Too many plants. 

[Streetwise]

Here is a photo after probably two years without a water change.

[Remi de Groot]

On 6/22/2021 at 11:49 PM, Mmiller2001 said:

You should ask yourself, are Nitrates the sole determinate factor in fish keeping? I ask myself that a lot, and the answer is no. There's way more chemistry going on and I want to operate at peak performance. Tanks like this, don't go a week without a 50% water change (or greater). Are tank like this everyone's goal, probably not, but do they want it to be? I respectfully, would ask anyone, not changing water, to show pictures of there tanks. And they will almost never look like these tanks. Is it worth it to not change water, IMO, nope.

Ask any person keeping tanks like these, and water changes are 1000% mandatory. 

 

One of the reasons 'tanks like this' do so much water changing is because they put way to much fertilizer in them or the substrate is leaking nutritions in the water that should go to the plants. All of this to make sure the plants never run out of fert (the Estimative Index for example).

And to have your aquarium look like this, just changing water is far from enough. You have to remove the plants very often, cut them and replant them. Especially the first picture you show with the Dutch Style.

Aquariums 'like this' are build for the plants and the fish are just a little extra. Most people on this forum keep aquariums for the fish...

[tonyjuliano]

@Mmiller2001 - yes, you have beautifully lush tanks, bursting with plants of many colors and texture. 

But do you really attribute this to frequent water changes?

I’m much more inclined to think that it’s due to the tremendous amount of effort and other maintenance that you perform, eg. plant trimming and management, testing and resulting fertilizer regimen, etc.

Yes, they are impressive, but some people desire a more “natural” environment. 

I mean no offense, the effort required to pull this off is apparent, and it’s obvious that the results you achieve are your goal.

But it’s not everyone’s.

[Streetwise]

I am a lazy perfectionist, so I want maximum uptime with minimal effort. I use organic soil to create a nutrient battery, and then I let it get recharged by fish waste and other decomposition.

I may reluctantly change water for my folks’ tank for visibility after nine months.

[Brandy]

On 6/22/2021 at 6:23 PM, Streetwise said:

I am a lazy perfectionist, so I want maximum uptime with minimal effort. I use organic soil to create a nutrient battery, and then I let it get recharged by fish waste and other decomposition.

I may reluctantly change water for my folks’ tank for visibility after nine months.

Woah. Is that tea? 😁 I am not a black water fan, but your folks are clearly tolerant! Still, super impressive balancing,

I have a tank or two like this that I just top off. My real reason for water changing is visibility or to remove algae/debris that are "in my way". The fish are never in need of a water change, but my top up water is RO water, so I really have trouble keeping my plants fed if I change water often. For me heavy/frequent water changes result in plant nutrient deficiencies. Sure I could dose more to compensate...but why?