# Modified Walstad Method



## FuryMonkey (Nov 5, 2017)

I haven't used pressurized CO2 in my Walstad tanks, but DIY CO2 in a large tank (so minimal increase in concentration) made a noticeable difference. Therefore even with poor circulation pressurized CO2 should be noticeable. Do note that Walstad tanks are expected to have good circulation.

Based on the theory behind Walstad, increased CO2 will benefit root feeders immensely. Fast growing stem plants might show deficiencies if you have very high CO2, light, and circulation. Dosing dry ferts would prevent this.

I love my Walstad tanks for their lack of maintenance; everything favours the plants over algae - however I will occasionally use DIY CO2 to make the plants a little bushier and healthier.


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## Petri (Jul 12, 2013)

FuryMonkey said:


> I haven't used pressurized CO2 in my Walstad tanks, but DIY CO2 in a large tank (so minimal increase in concentration) made a noticeable difference. Therefore even with poor circulation pressurized CO2 should be noticeable. Do note that Walstad tanks are expected to have good circulation.
> 
> Based on the theory behind Walstad, increased CO2 will benefit root feeders immensely. Fast growing stem plants might show deficiencies if you have very high CO2, light, and circulation. Dosing dry ferts would prevent this.
> 
> I love my Walstad tanks for their lack of maintenance; everything favours the plants over algae - however I will occasionally use DIY CO2 to make the plants a little bushier and healthier.


Thanks. But my tank has like zero water movement/circulation lol. 

I thought walstad method is to make the plants become the filter so a filter is not necessary? Or did I get this wrong - Walstad method recommends a filter/power head for circulation until all the plants are established and after that you can remove them?

I don't like using a filter or power head because I don't like having stuff on my glass rim or inside my tank . I like it bare


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## FuryMonkey (Nov 5, 2017)

Circulation helps move nutrients and gases; especially with surface agitation, it ensures that the water is oxygenated and helps dissolve CO2 from the air back into the water while the lights are off. 

With a fresh tank the surface agitation isn't necessary since the soil microbes will be producing plenty of CO2 for awhile yet, but the plants (especially stem) will get better access to nutrients and have better gas exchange with some circulation.

How do you intend to add CO2 without circulation? Just bubbling with a diffuser? The rising gas will move water and create some circulation - diffusion will also move CO2 throughout the tank quite well. Diffuser placement will influence how evenly the CO2 is distributed - less of an issue in small tanks - you might see some plants benefit more than others, but all plants will grow much faster and healthier. 

While I obviously recommend some means of circulation, CO2 is so limiting in planted tanks that any tiny increase in concentration is very noticeable.


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## Petri (Jul 12, 2013)

FuryMonkey said:


> Circulation helps move nutrients and gases; especially with surface agitation, it ensures that the water is oxygenated and helps dissolve CO2 from the air back into the water while the lights are off.
> 
> With a fresh tank the surface agitation isn't necessary since the soil microbes will be producing plenty of CO2 for awhile yet, but the plants (especially stem) will get better access to nutrients and have better gas exchange with some circulation.
> 
> ...


Thank you for your reply.

I didn't know the soil can produce CO2 actually.

Guess what, I went around to look for a water pump and found a really really small one!!

Here's my setup with the tiny pump. In the future, I might want to add in a DIY CO2 with cigarette filter just underneath the intake of the pump for better CO2 circulation.

Thinking of adding some pieces of wood with moss attached on the bottom right there. Any suggestions? I thought of fissidens but I heard the growth rate is extremely slow but I really love the shape and texture!!


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## Bananableps (Nov 6, 2013)

Petri said:


> I thought walstad method is to make the plants become the filter so a filter is not necessary?


Walstad herself uses canister filters with empty cartridges, but does not really express a very strong opinion about how the circulation is achieved. But your tank seems to be doing great without circulation.



Petri said:


> I didn't know the soil can produce CO2 actually.


Yup! Many rooted plants can even obtain CO2 directly from the substrate. This means that a lot of the CO2 (as well as other nutrients) in a dirted tank are available only to vascular plants, not algae. Aquasoil, as far as I am aware, does not provide this benefit.



Petri said:


> Thinking of adding some pieces of wood with moss attached on the bottom right there. Any suggestions? I thought of fissidens but I heard the growth rate is extremely slow but I really love the shape and texture!!


Fissidens doesn't grow _that_ slow. Sure, maybe not as fast as java moss, but java moss grows _really_ fast. If you want fissidens, treat yourself!


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## splattered (Jun 7, 2017)

Best tiny pump I've seen is a cat water bowl pump - like for cats. I took it apart and found a great TINY submersible pump. Less surface agitation means less co2 escaping out into the air

Sent from my SM-G730V using Tapatalk


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