# How to do weekly water changes on non-CO2?



## Minsc (Jul 9, 2006)

I've often done water changes on non-CO2 tanks, and never had an algae bloom afterwords. Then again, I'm pretty sure my water doesn't have elevated levels of CO2.

Do you have any reason to suspect your tap has high levels of CO2?


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## lauraleellbp (Feb 3, 2008)

I do about 20% every 2 weeks on my low tech (non-CO2-injected) tanks. I've never worried about CO2 level fluctuations from water changes; my tanks are well-circulated and have HOBs with waterfalls/biowheels, so I don't imagine the levels fluctuate that much.


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## discuscardscorys (Jul 29, 2008)

the way i avoid the problem is by maintaining very good circulation, and therefor gas exchange. by keeping the co2 level similar to what is in the air, you eliminate the difference between the tank water and the water you are adding (or so it seems to me)


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## customdrumfinishes (Apr 4, 2008)

never heard of a co2 spike after water change, i have 3 tanks without co2, do 20-30% every 2 weeks with no problems.


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## El Exorcisto (Aug 5, 2008)

Do them at night after lights-out... Problem solved


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## KDahlin (Mar 12, 2007)

Huh! This is very enlightening! I must have algae problems for another reason. That's really interesting to hear that other people do frequent water changes in non-CO2 tanks without algae problems. Now I don't know what to think...


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## epicfish (Sep 11, 2006)

KDahlin said:


> Huh! This is very enlightening! I must have algae problems for another reason. That's really interesting to hear that other people do frequent water changes in non-CO2 tanks without algae problems. Now I don't know what to think...


I do the same. Just drain the water and fill'er back up without problems. Although I do dose 1.5x Excel when I do WCs on every tank I do. It's become habit. Maybe that helps a little bit? No clue.


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## KDahlin (Mar 12, 2007)

Well, maybe I misread this article. That's what I took away from it: http://www.barrreport.com/articles/433-non-co2-methods.html


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## epicfish (Sep 11, 2006)

Tom Barr said:


> Doing water changes adds CO2 back to a CO2 limited tank.
> Plants and algae both can and do adapt to low CO2 environments and induce genes to make enzymes that concentrate CO2 around Rubisco, the CO2 fixing enzyme. When we add the CO2 at higher levels back, this causes the plants and algae to destroy the low CO2 enzymes and start growing without of them since they no longer need them to fix CO2 form the KH ( the -HCO3).
> Why keep all this machinery around if you no longer need it? Doing weekly water changes "fools" the plants and helps encourage algae more. Algae are faster to respond to low CO2 than plants.
> Once the plants do adapt, they can do well.


Interesting. If you do water changes with plenty of surface turbulence, is the level of CO2 in the aerated tap water still much greater than the level of CO2 in a non-injected tank? And what if you do WCs with less volume. Maybe 2-3 gallons vs. 4-5 gallons in a 24 gallon tank?

Maybe Barr will chime in on PT.


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## discuscardscorys (Jul 29, 2008)

as i understand it, excel and non excel are two completely different setups
my excel tank has no issues with algae when i do water changes where as my non-excel tank did until i took the hood off, hung the light and increased surface agitation.
my next setup is going to be non co2, non excel but with a wet-dry filter...has to wait till Christmas vacation though


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## KDahlin (Mar 12, 2007)

discuscardscorys said:


> as i understand it, excel and non excel are two completely different setups
> my excel tank has no issues with algae when i do water changes where as my non-excel tank did until i took the hood off, hung the light and increased surface agitation.
> my next setup is going to be non co2, non excel but with a wet-dry filter...has to wait till Christmas vacation though


I have experimented with Excel on this tank and was unable to see a difference.


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## mistergreen (Dec 9, 2006)

15% water change really isn't that much.

and an easy way to lower your changes of an algae outbreak is not have too much light.


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## nikonD70s (Apr 6, 2008)

i do about %70 water change every week on my low-tech no co2 60 gallon tank. and no algae bloom what so ever, and the tank looks super clean and clear after every change. could be my tap water? i dont know i never check any of the water paremeters.


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## Aquarist_Fist (Jul 22, 2008)

I would assume that a large ammount of the CO2 is outgased when the water splashes from the faucet into the bucket, when Prime is added and everything stirred etc. 

And even if not: assuming that you don't have *really* elevated leves of CO2 in your tap water, there will hardly be a spike...a spike looks like this: ^


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## KDahlin (Mar 12, 2007)

nikonD70s said:


> i do about %70 water change every week on my low-tech no co2 60 gallon tank. and no algae bloom what so ever, and the tank looks super clean and clear after every change. could be my tap water? i dont know i never check any of the water paremeters.


I don't understand that. That goes against the theory. Maybe I should do a poll of non-CO2 users who do weekly or frequent water changes and find out how many have algae.


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## Minsc (Jul 9, 2006)

I think Tom Barr may have elevated CO2 in his water that screws up his tanks
I've never seen any issue arise from water changes myself.


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## BradH (May 15, 2008)

I was doing weekly water changes in my non co2 low light tank. I started getting algae. I didn't realize that I was doing anything with co2 fluctuations by doing the water changes. I'm now going to stop doing water changes and treat it like Diana Walstad and Tom Barr suggest.


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## Lucky_13 (Apr 18, 2006)

I have always thought that weekly water changes (every two weeks with low bio load) is necessary for every tank, regardless of low tech, high tech, low light, high light, whatever. I've always done about 20% every week, 50% on higher bio-load tanks and the only algae problems i've ever gotten was some black hair algae that I cleared up with hydrogen peroxide and blue green algae from low nitrates.


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## BradH (May 15, 2008)

Lucky_13 said:


> I have always thought that weekly water changes (every two weeks with low bio load) is necessary for every tank, regardless of low tech, high tech, low light, high light, whatever. I've always done about 20% every week, 50% on higher bio-load tanks and the only algae problems i've ever gotten was some black hair algae that I cleared up with hydrogen peroxide and blue green algae from low nitrates.


I think this applies to low light, non co2, heavily planted tanks. The plants and fish balance everything out. If you have co2 or highlight, then you can do the water changes. Thats what I've gathered from reading and from talking to Tom on his site. I'm no expert, hence why I seeked him for advice, but as long as he's been at it, I'm going to trust he knows and do it the way he suggest.


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## KDahlin (Mar 12, 2007)

I would agree with you BradH, Tom Barr is the expert and that's why I definitely listen to what he has to say. But it's worth questioning here why a number of people have attested to doing weekly or frequent water changes on their non-CO2 tanks without encountering algae problems. I'm wondering why this is.


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## BradH (May 15, 2008)

KDahlin said:


> I would agree with you BradH, Tom Barr is the expert and that's why I definitely listen to what he has to say. But it's worth questioning here why a number of people have attested to doing weekly or frequent water changes on their non-CO2 tanks without encountering algae problems. I'm wondering why this is.



I would like to know as well. However he did say that if you use excel, then you DO need to do the water changes.


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## lauraleellbp (Feb 3, 2008)

I think you need to look at your plant mass versus biomass versus lighting.

There's no "one size fits all" in planted tanks- just general guidelines that you experiment with to see what works with your own tank.

No one's water parameters, lighting, PAR, biomass, plant mass are ever EXACTLY the same- even from tank to tank within the same household.

I've got algae in my tank, but as long as it's not overtaking my plants I don't worry about it. Keeps my Amano shrimp and Otos well-fed.


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## Homer_Simpson (May 10, 2007)

KDahlin said:


> ... Maybe I should do a poll of non-CO2 users who do weekly or frequent water changes and find out how many have algae


FWIW, I set up a 5 gallon non co2 hex tank as per Tom Barr's method with some variation. The tank was set up March 2008. The inhabitants were Amano Shrimp and an otocat. The plants included: tiger lotus, ambulia, onion plant, anubias, crytopcorne.

Water changes have been 50% weekly followed by a pinch of phosphates, potassium, calcium sulphate, magnesium, and trace mineral. I dose about 3x recommended dose of Excel for a 5 gallon tank and have been doing so since the tank was set up. I have not noticed any ill effects on the plants or inabitants at that dosage. Why such huge water changes? I am biased towards such water changes as I have found in my 8 years of keeping fish that such water changes have heavily contributed to longer fish surival rates. Also, considering that Amano Shrimp and Otos tend to be more sensitive to water quality, I don't like to take chances by doing infrequent water changes. For me water changes are more than for the plants, they are about short term and long term health of my inhabitants. 

As far as algae goes, I had a diatom algae bloom a month of the tank being set up. This is not unsual and most newly planted and non-planted tanks often develop diatom algae. The otocat made short work of the diatom algae. This was followed by green dust algae that lasted about two months and disappeared without any action on my part. It seems that the water became increasingly clear and the plant growth appeared to get better over time. I used a layered substrate(dusting of peat, crushed Seachem fert tabs, leonardite, thin layer of schultz aquatic soil and onyx sand cap). The plants appeared to really like the substrate right off the bat and laid out deep thick roots, which I believe contributed to healthy short term and long term plant growth and may explain why the tank has done as well as it has.


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## KDahlin (Mar 12, 2007)

BradH said:


> I would like to know as well. However he did say that if you use excel, then you DO need to do the water changes.


When I use Excel on my 24 gallon tank, it seems to exacerbate the algae problem.


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## plantbrain (Dec 15, 2003)

KDahlin said:


> Well, maybe I misread this article. That's what I took away from it: http://www.barrreport.com/articles/433-non-co2-methods.html


there are some caveats: if you have a balanced tank, then removing water and removing the nutrients, which are often very low, will lead to algae, if you over load the non CO2 planted tank, then the issue is very different.

Smaller % works better, try 50% if you want to test it.

Alan had a lot of issues with a large predator tank and went to daily automated water changes and got rid of the algae. He could not use CO2 well in the tank either. So this took care of things.

Point is, you do not need to do water changes and light, the type of plants, whether some are floating, out of water make a large difference, tap water etc likely as well and general stability. If you added a lot of plants from the start, then life is likely pretty good. 

I have little issue with a mat of floating water sprite and higher current African rift tank doing water changes, the tank was loaded and the fish produced too much waste. The CO2 was not an issue as the plants are easy to grow and float.

I think the issue is really based more on folks with too much fish and they have to do water changes vs a balancing the plant/fish load. So why do the no water change tanks do so well? Have you tried not doing them or doing larger % water changes? Measure CO2 before and after the water changes?

Try it and see.

Regards, 
Tom Barr


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## Bugman (Jan 7, 2008)

plantbrain said:


> I think the issue is really based more on folks with too much fish and they have to do water changes vs a balancing the plant/fish load. So why do the no water change tanks do so well?


I now have 4 low/med light non Co2 tanks. Before starting the first one I read some post from Tom about balance in a low light and no water changes. That is what my intent was with these tanks and it has worked very well. The tanks are heavily planted and not maxed out on fauna. I do dose with excel every other day. I have excellent plant growth with healthy plants and the fish do very well also. NO water changes are done at all unless something goes really wrong. I simple top off due to evaporation. I have 3 tanks that get a 50% change weekly due to EI. If I had to do water changes on all 7 tanks I would have to throw up the white flag.


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## KDahlin (Mar 12, 2007)

plantbrain said:


> there are some caveats: if you have a balanced tank, then removing water and removing the nutrients, which are often very low, will lead to algae, if you over load the non CO2 planted tank, then the issue is very different.
> 
> Smaller % works better, try 50% if you want to test it.
> 
> ...


My 24 g is not heavily stocked. I have a pair of dwarf cichlids, 3 emperor tetras, 2 otos, and 4 or 5 Amano shrimp. It's densely planted with bolbitis, anubias, java fern, and a few crypts. My problem with no water changes is I don't like the way no water changes tanks look. They don't look vibrant. I tried going for a period without water changes and I finally gave in; I couldn't do it. I didn't like looking at my tank. I don't like looking at it so much with algae either. Right now the algae is particularly bad because I experimented with adding Excel - big mistake. I increased the ferts too with the Excel but the algae got worse. 

I'll experiment with doing larger water changes; 50%/week. I had been doing 20%.

Thanks


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## BradH (May 15, 2008)

So your saying that when you added excel it caused algae. Hell, I'm all confused now. lol

I have been adding excel to try to kill some bba myself.


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## KDahlin (Mar 12, 2007)

BradH said:


> So your saying that when you added excel it caused algae. Hell, I'm all confused now. lol
> 
> I have been adding excel to try to kill some bba myself.


Spot treating with Excel will kill algae. Also, using dosages in excess of Seachem's recommended dose when using Excel as a carbon source, has been found to control algae.

In my tank, I used Seachem's recommended dose - and found that it exacerbated my algae situation. I have not tried overdosing Excel in this tank.


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## BradH (May 15, 2008)

KDahlin said:


> Spot treating with Excel will kill algae. Also, using dosages in excess of Seachem's recommended dose when using Excel as a carbon source, has been found to control algae.
> 
> In my tank, I used Seachem's recommended dose - and found that it exacerbated my algae situation. I have not tried overdosing Excel in this tank.


I didn't realize you had to overdose it though. So I'm probably making my algae worse then? Cause I just starting adding it per dose instructions on the bottle. I mean I know about overdosing it, but I didn't think you had to do that to kill algae. I though you could just start using excel and get your co2 stable and everything would balance out. So I guess I read something wrong then.


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## KDahlin (Mar 12, 2007)

BradH said:


> I didn't realize you had to overdose it though. So I'm probably making my algae worse then? Cause I just starting adding it per dose instructions on the bottle. I mean I know about overdosing it, but I didn't think you had to do that to kill algae. I though you could just start using excel and get your co2 stable and everything would balance out. So I guess I read something wrong then.


No, I don't think you're necessarily making your algae worse. My experience with it in this tank is not the norm. You can read more about algae and Excel here: http://www.aquaticplantcentral.com/forumapc/algae/3806-flourish-excel-got-rid-all-my.html


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