Walstad Setup Aquarium.... Pros and Cons? Experience/ Opinions

guys i was wondering how much space would the dirt and the gravel cap take. currently, i have about two inches of eco complete and it takes about 3-5 gallons not sure in my 20 gallon tank. so if i have 2 - 2.5 inches soil and then 1.5 cap gravel, how much water would i be left with?
 
I usually hear 1" of soil with 1" of gravel cap. How much of a cap would you use with sand though?
I'd do 1" of sand also.
so one inch soil, one inch eco complete in my case?
Yeah that sounds fine.

I think the only reason why you wouldn't want a really deep cap of sand is to help prevent anaerobic areas but IDK.
 
I strongly suggest 2" of a cap. Planted, replanting, fish looking for food...you don't want a muddy mess.
 
I don't know, but in a lot of reading, I've seen that phosphates are responsible for algal blooms. I thought phosphates were a by-product from the ammonia produced by breaking down of organics, such as what's found in dirt. I'm probably wrong...

Depends on the setup. In a saltwater tank, yes. In a freshwater tank without plants, probably. In a freshwater planted tank, plants should be absorbing the nutrients. Maybe if there was such a surplus of nutrients that the plants couldn't absorb it, but otherwise the plants should keep up if their other needs are met.

What could do an algae bloom is new sand. There is a connection between silica sands and diatom blooms, but that'll happen with any use of silica sand and so wouldn't count as a con for this method.
 
What could do an algae bloom is new sand. There is a connection between silica sands and diatom blooms, but that'll happen with any use of silica sand and so wouldn't count as a con for this method.

I've always heard "there is a connection between silica sands and diatom blooms" but never seen ANY scientific data supporting this claim. Not saying it's not true, just saying I've never read any concrete scientific data.

Also, algae blooms and soil substates, I know from my own experience, if I replant a large portion of my soil tanks, I get a green algae bloom. I expect it. I have no idea why I get this algae bloom, but it happens every time.
 
What could do an algae bloom is new sand. There is a connection between silica sands and diatom blooms, but that'll happen with any use of silica sand and so wouldn't count as a con for this method.
I've never gotten diatoms until I started using sand... Interesting...

I know you're supposed to use just a shallow layer of soil but that can't make for great root health, can it? I mean, yeah it would improve the CEC but wouldn't the plants become root bound? I dunno if aquatic plants have the same issues with getting root bound as non-aquatics do though...

I would love to see some kind of substrate that looks like what I find at the bottom of natural bodies of water. It's a sandy soil but the sand doesn't separate from the soil. I guess the potting soil or mineralized soil is the best imitation of that though.
 
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