How To Set Up An Algae Free Lowtech Tank On A Budget

  • #1
HI FishLore,

I recently donated and setup an aquarium for a classroom a few weeks ago and it's entirely lowtech/budgeted. Here's what I did to ensure that it was algae free.

The Setup:

Tank Size: Standard 10 Gallon

Lighting: 2x Phillips Daylight Deluxe 6500K CFL bulbs that are attached via clip on Gooseneck lamps (total cost came to ~$30 for the lighting)

Substrate: 3" layer of Home Depot Prewashed Play Sand ($5) (No soil, no osmocote+, no root tabs)

Filtration: Some generic hang on back, it's pretty small and weak though (~$20) The filter cartridge already had some established bacteria on it.

Heater: None, the classroom doesn't really drop below 65F

Fertilizer: Thrive by NilocG

The Plants:
I often recommended that tanks are planted like a jungle in the beginning to prevent algae. This was no exception. I absolutely stuffed this thing with plants and I still think that I should've added more. For just a standard 10 gallon, here are the plants I used (grown by me, submerged and algae free to start with. They were all grown with CO2 and high ferts too)

5 stems of Limnophila Heterophylla

10"x6" mat of Dwarf hair grass (DHG)

10 stems of Water Wisteria

20 or so stems of Rotala green and Rotala H'ra

10 red/bronze crypts

30 Stems of Pearlweed

6 Stems Pogostemon Quadrifolius AKA Pogostemon Octopus

5 HUGE 1.5ft+ pieces of Brazilian Pennywort

That's a quite impressive for just a 10 gallon stocking, but again, it has to be a jungle. And keep in mind that this was barely enough. The tank must be a jungle from day 1.

Please notice, all of the plants I used were extremely fast growers (with the exception of crypts and DHG). You absolutely need fast growers for a successful algae free lowtech tank! None of this anubias, java fern, crypt dominant tank. There's nothing wrong with having them, but they should not make up the majority of the biomass. The majority of the biomass needs to be the heavy hitting fast plants like wisteria and limnophila heterophylla (the limnophila is especially insane, it grows even faster than my anacharis, wisteria, and hornwort).

In the beginning, there was 0 melt! Absolutely no melt even from the crypts. And these plants were grown hightech and transitioned to lowtech with no melt. Why is this? If the plants were grown submerged in hightech parameters, they transition easily because as long as the light is lower, their CO2 demand is lowered drastically and they already have an abundance of stored nutrients to help them transition easily. It is a myth that hightech plants cannot transition properly to lowtech. It is absolutely no issue as long as you give the plants what they need. The big issues occur when there is too much light, no CO2, and no ferts. Low-medium light and a decent amount of ferts are enough for most of the plants available in the aquatic hobby.

The Secret to No Algae:

Two things were important here. One was the fact that I dosed a complete fertilizer. I dosed 1 pump of Thrive per week. Just one pump, no more, no less of a full complete fertilizer. The plants love it. They are in good health. An abundance of healthy plants generally equate to no algae.

The second, probably the MOST important thing was that I let some of the plants grow emersed. The huge brazilian pennywort pieces are rooted in the substrate, but they are growing emersed outside of the 10 gallon. Here's the logic behind it:

In order to prevent algae in an ecosystem, the plants themselves must produce allopathic chemicals to inhibit algae growth. In a submerged system, the plants only produce these chemicals when they have access to an abundance of CO2. That's why hightech tanks are generally algae free because the CO2 gives the plants a huge boost in the growth and functions they can perform.

In a lowtech system, there isn't nearly enough CO2 for the plants to perform this function. However, if the plants grow emersed, then they have access to unlimited CO2. If half the plants is submerged and the other half is growing out of the water, the entire plant benefits from the atmospheric CO2. When it is able to get access to this CO2, the whole plant secretes allopathic chemicals in the water which helps greatly to reduce algae. So why did I choose brazilian pennywort for this project?

Brazilian pennywort has leaves with a HUGE diameter. When it grows emersed or floating, it's leaves can reach up to 3" in diameter. It also grows very fast. If the pennywort is allowed to creep along the surface and also climb out of the tank, the leaves have a large surface area to access CO2 and a large surface area to secrete these allopathic chemicals.

My method of emersed growth in a lowtech tank is nothing new. It is what Diana Walstad used in her technique of walstad tanks. That also is another reason why most walstad tanks are not successful at all. Most people neglect the fact that Walstad tanks NEED to have emersed growth and a significant amount of it in order to have an algae free tank. She's a huge supporter of the allelopathy theory in aquatic plants.


I'll likely be adding red cherry shrimp and 5 small endler/guppy hybrid males. I haven't added livestock in the first couple of weeks to let the tanks cycle out.

Above: Before
Below: After

  • #2
wow looks great!! Maybe you should throw in some Ludwigia P. or Ludwigia. R / Deep red to contrast the green colors even more.
  • #3
Your tank is beautiful ! For your next bottle of NilocG fertilizer, buy Thrive C instead. It’s made specifically for low tech tanks.

That’s what I use and I have really good stability (so far).
  • #4
I love your knowledge on plants, thanks for sharing
  • Thread Starter
  • #5
wow looks great!! Maybe you should throw in some Ludwigia P. or Ludwigia. R / Deep red to contrast the green colors even more.

Thanks! I might end up doing that, but for now I'm just leaving it be because I just made this tank out of the plants that I was going to throw away otherwise.

Your tank is beautiful ! For your next bottle of NilocG fertilizer, buy Thrive C instead. It’s made specifically for low tech tanks.

That’s what I use and I have really good stability (so far).

Thanks! I've had many clients use ThriveC with great success. One of my clients even grows rotala H'ra and gets it pink with just ThriveC and a Nicrew LED. I already had a bottle of regular Thrive on hand so I just decided to use that one.

I love your knowledge on plants, thanks for sharing

No problem at all! I like making guides like this so that other hobbyists and my clients can both set up the planted tank they've always wanted
  • #6
Damp.... wish I knew about thrive c before spending dough on those other bottles...

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