Walstad Tanks and Modifications

[xfretz]

Hello!

I recently tried setting up a soil substrate aquarium after years of just keeping anubias and Java fern. I went with about an inch of organic potting soil and then 1.5 inches or so of medium gravel. Following along pretty closely with the Ecology of the Planted Aquarium by Diana Walstad. I know that nitrogen leaking from the soil was going to be substantial at least at first, but the ammonia was around 1ppm for a week straight and I didn’t feel comfortable stocking it. Also, I found the biofilm that developed from lack of surface agitation really nasty, but I didn’t want to agitate the surface with an air stone or sponge filter and release all the CO2 from the water.
 

At this point I stumbled across Diana Walstad’s website, and she had a supplemental article on potting plants instead of a full soil aquarium. https://dianawalstad.files.wordpress.com/2021/11/potted-pl-revisions-1.pdf
 

I potted a few of my sword plants with the same soil and gravel cap in my 55 gallon with a sponge filter, and the water parameters have all been fine. 
 

Has anyone else experimented with potting root growers like sword plants or val? And how much does loss of CO2 from the surface agitation of a sponge filter REALLY hinder plant growth? What are your thoughts/experience? 
 

Thanks!

[Guppysnail]

I try to make certain I have no surface dead spots for extra O2 for my fish. It does not affect my plants. Having a siesta actually boosts them but even without they do fine. I’ve used plenty of pots with swords and bulbs and stems. No issues until they get big. Then the roots filled the pots and consumed all the nutrients and with no water flow to the bottom to replenish nutrients my plants started struggling. I used gravel and no root tabs or fertz or organic soil though.  It took months and months before I noticed growth slowing. With organic soil it would probably take much longer. 
 

As you see in the photo the roots were pristine clean. They had consumed every drop of mulm. This one was an Aponogeton bulb. It’s the only one I took a picture of but the swords and ludwigia were similar.

Edited May 17, 2022 by Guppysnail
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[xfretz]

On 5/17/2022 at 8:04 AM, Guppysnail said:

I try to make certain I have no surface dead spots for extra O2 for my fish. It does not affect my plants. Having a siesta actually boosts them but even without they do fine. I’ve used plenty of pots with swords and bulbs and stems. No issues until they get big. Then the roots filled the pots and consumed all the nutrients and with no water flow to the bottom to replenish nutrients my plants started struggling. I used gravel and no root tabs or fertz or organic soil though.  It took months and months before I noticed growth slowing. With organic soil it would probably take much longer. 
 

As you see in the photo the roots were pristine clean. They had consumed every drop of mulm. This one was an Aponogeton bulb. It’s the only one I took a picture of but the swords and ludwigia were similar.

Interesting, the swords grew in a pot with just gravel? Also, I use a short siesta with the lights, are you referring to a siesta with the air stone or filter? That’s a cool idea.

[Guppysnail]

Yup in a pot just gravel. I do have higher bioloads and feed generously. Also my tap water read like liquid fertilizer from agricultural runoff with 25-35 nitrate out of the tap.  Lighting siesta. 

[xfretz]

On 5/17/2022 at 8:27 AM, Guppysnail said:

Yup in a pot just gravel. I do have higher bioloads and feed generously. Also my tap water read like liquid fertilizer from agricultural runoff with 25-35 nitrate out of the tap.  Lighting siesta. 

Gotcha! My tap water doesn’t have nitrates but is really hard, so I’m hoping between that and the soil I can keep enough nutrients in there without having to dose too much fertilizer or try to squeeze root tabs through the gravel to the bottom of the pot.