Low Tech - no filter 20g planted tank experiment.

[Galactik]

I suppose low tech can mean many things to many people.
Here in Panama, if any stagnant water like a tank is found without moving water, its an automatic $100 fine by the health dept. mosquito police (1st offense), and they visit once/month.
On the upside, heaters are not needed, and I don't use any artificial light, only the indirect sun, hitting the tank mouring and late afternoon.
To keep water moving, a pump, and sump are used on the 180 gal, what I consider, my "low tech concept".
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It is heavily planted with aquatic, and terrestrial plants, and contains 16 fish all in the 3"-5" range, except the 1 goby at 10+" (mostly all plants were collected. and all fish are wild from here in Panama).The obvious exception is an Amazon sword plant bought in a LFS, that has had a hard time competing with the wild plants, so was moved to a semi-submerged floating log. Some of the aquatic plants collected, like Hyacinth and Hydrocotyle, didn't survive being under a patio roof, with only indirect sun. The survives are Hydrilla, and Vallisneria.
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I do daily small water changes, (old water is taken from the surface) using that water on the garden, and for flushing toilets, and the tank leaks a little due to the regular earthquakes.
The substrate is never vacuumed to provide organic nutrients for the plants, and sea shells are in flow to the sump, to add calcium.
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The sump is in direct sun, so algae also helps sucking up extra nutrients, the tank itself has very little algae
It has been set up about a year, and even with my lazy water change schedule of late, nitrate reads between 0-5ppm.
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and pH hovers around 8, (slightly lower early morning, higher in the late afternoon as the plants use up the CO2) like the waters the fish and plants came from.
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The fish are
a dozen Andinoacara coerleopuntatus
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2 Roeboides tetras
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a Panamanian Plecostomus
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and the big goby
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A few months ago I added water lilies acquired from a local aquarist.
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The terrestrial plants were collected here on the island.
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Those are beautiful!

I guess I understand the mosquito control thing, but you would think that would pass since you have fish in it as well. My fish go crazy every time something flies near the surface. They dont even get a chance to lay eggs or nothing lol

 

[Galactik]

Look nice! Do you feed the snails? After a while, the organic top soil will run out of nutrients, and you will need to replenish nutrients by dosing and/or WC.

I feed sparingly to try and avoid algae-so far I've had none- but when I do, I toss some of my stale fish food and things like that.

I also leave the trimmings from the swords to decay as they start eating those as well.

 

[duanes]

Here dengue, and Malaria are major concerns, so fines are considered needed by the powers that be, to make sure local residents aware of the dangers of any standing water, and get rid of them. Luckily the small cichlids and tetras in my tank are effective mosquito larvae eradicants.

 

[Ulu]

Here it's the Nile Virus they fear.

 

[tiger15]

I kept outdoor planters with fish for a couple years and gave up. Now I only keep them to cultivate daphnia. Even in northeast US, the water gets too warm in summer sun, and fish suffer. For daphnia, I can harvest them only during spring and fall as they go into dormancy during summer heat and winter cold.

To control mosquito, I covered the top with window screen. If you use fish to control mosquito, you need small guppy size fish. People who keep koi pond has to throw in guppies to eat mosquito larvae as big fish don't.

One way to keep container water cool under summer sun is to bleed tap water into the container continuously. Florida fish farms feed well water in from one end of their concrete containers or ponds and bleed out at the other end continuously, so the temperature is kept constantly at 72F year round.

Stagnant water in container with plants or algae will go through diurnal pH gyration. My window sill planted bowls go through daily pH gyration from 7.2 before sunlight period to 8.8 at peak of sunlight. With algae eating snails and shrimp, the glass and water are crystal clear with no algae except green spirogyra which they don't eat and I have to pull out by hand from time to time. I heard that API Algaecide can control spirogyra but I am afraid to use it for fear of killing invertebrates.