A lushly planted low tech tank by John Chang with a mix of easier and slightly harder plant species. Good understanding of what makes a low tech tank work well allows us to have lush, healthy tanks without requiring CO2 injection.
The simple definition has nothing to do with actual technology; the term low tech just refers to planted aquariums that run without injected Carbon dioxide (CO2) – this is to do with historical convention, when CO2 injection equipment was deemed high tech in the past.
Nonetheless, many plants can grow well without injected CO2 and having a thriving planted aquarium without CO2 injection is definitely achievable by most aquarists. This approach requires far less equipment and technical knowledge than CO2 injected tanks; many fish-only setups can easily be converted to having thriving plants given a few smart tweaks. The plants provide a great environment for fish by filtering the water and providing a natural environment.
Plant selection
Choose a plant selection that works with low CO2 conditions.
This include plants such as Java fern, Anubias species, Water wisteria, Dwarf saggitaria, Vallisneria species, Ludwigia Repens, Java moss, Marsilea species, Rotala rotundifolia, Pearlweed, Sword plants, Red/green lotuses, Water wisteria, Water sprite.
This tank demonstrate great choices for a low tech tank. Cryptocorynes are used on the substrate and narrow leaf Java fern are used on the hardscape. The red plant on the top left is limnophila aromatica.
A low tech planted aquarium by George Farmer from the UK. Check out his instagram and youtube channel. This tank also shows how having substantial hardscape (compare the size of the wood to George, standing at the side) forms the back bone of the aquascape.
Create impactful hardscape
Choose easy planted tank plants, but implement complexity through hardscape work.
This delivers much nicer results than being overly ambitious with demanding plants.
This hardscape-only tank on the left by ADG group (visit them to see their hardscape materials) shows that hardscape alone can create stunning aquascapes.
Use soil substrate
Use a soil based planted aquarium substrate.
Soil based low tech planted aquariums consistently out-perform those that use inert (sand/gravel) substrates. They provide a long term store of nutrients for plants.
Organic decomposition of soil releases carbon that aids growth.
Many plants root better in soil and it encourage bacteria colonization, which has a stabilizing impact on the tank environment.
It also offers much better success rates for growing plants that otherwise require CO2 injection to grow well – this include plants such as Monte carlo, staurogyne repens & alternanthera reineckii. Commercial pellet aquasoils are much less messy to handle compared to using raw soils, and deliver more predictable results due to the consistency of the product.
This is Dennis Wong’s 1 gallon low tech vase, using a mix of raw soil with an aquasoil cap. The pelleted commercial aquasoil keeps the fine particles of the raw soil down and is easy to plant in.
Plant densely at the start
Plant densely at the start prevents algae from getting a foot hold.
Plants also have a stabilizing effect on the eco-system of the tank; up-taking waste products such as ammonia and absorbing heavy metals.
Tank space should be at least 50% planted at the start. Having a sparsely planted tank is an invitation for algae to spawn and occupy the space.
Most tanks reach stability once plant mass dominates 70%+ of the available space. A fully planted tank is the best defence against algae. This is mini 3 gallon low tech tank using raw soil as planted aquarium substrate base. Tank is virtually algae free as healthy plants out-compete algae.
Shallower tanks are easier
Shallow tanks are much easier to manage; better gaseous exchange and easier lighting options – its much easier to light a shallow tank than a deep one.
This makes a bigger impact than people realize. Low tech tanks benefit tremendously in this aspect.
A wide shallow tank such as the one to the right by Tom barr makes it easy for aquatic plants to grow above the water surface.
Small, but regular doses of fertilizer
Low tech tanks also do far better with regular fertilization, small weekly doses of fertilizer is sufficient.
”No fert, no dirt” tanks are essentially a bet that your water supply contains all the essential elements for plant growth.
Livestock waste is rarely adequate for optimal plant health. No fish I know off poops out chelated iron for example. Unless you are sure your tap is rich in all the required elements, having regular doses of fertilizer impacts plant health greatly.
Dosing large amount of nutrients (EI style heavy dosing) is an invitation for trouble. A tank with low demand plants such as the one below only need to be fertilized once or twice a week at much leaner levels.
This layout by Hiep Hong demonstrates good use of hardscape. This would make a terrific display tank for fish with relatively low maintenance required.