Filtration of a plant-only tank... is it necessary?

[Martin]

Happy Thankgiving all!

Just as the title says.  I'm basically considering using a spare tank as a nursery.  All of my tanks do have bladder snails and I am assuming those will likely make their way into this tank as well, but apart from that, the plan is plants-only.  That being said, is filtration a necessary thing?  I just wasn't sure if a stagnant tank was good or not.  Thanks guys!

Martin

Edited November 23, 2022 by Martin

[MattyM]

That is a great question 🤔 - I wonder if just surface agitation for gas exchange is what you're after. 

Edited November 23, 2022 by MattyM

[Expectorating_Aubergine]

You don't have to filter a plant only tank. Heck, you don't have to filter a tank with growing plants in it. What you do need is water movement. The easiest way to achieve this is with an air stone, or a power head that has a venturi nozzle. Personally, I'd go with the air stone. One thing you will have to do is fertilize. Since you won't have fish in there to "feed the  plants". If you want to do this super easy mode, I would suggest you grow emersed. Your get faster growth, thus more plant material to work with. The  you don't have to worry about algae, which is a legitimate concern  when dosing ferts. There is the issue of melt when plants go from above to below the water line. Honestly though, you'll have so much plant material that it will be worth it.

Edited November 24, 2022 by Expectorating_Aubergine

[Jungle Fan]

If my tank of 75 gallons were plants only without fish and invertebrates I would still run the filter for flow, and the surface skimmer to prevent the surface residue film. I would also continue to run my air stone at night when the plants actually consume oxygen instead of producing it. That said I've seen beautiful aquaria, especially 180 and 200 gallon tanks without any of these where it was just the plants maintained by liquid fertilizer and root tabs. If you are looking to run a heavily planted tank without livestock, and filtration I recommend looking into Diana Walstad's book. Just running a plant only tank does not eliminate the worry about algae, unless proper fertilization is offered and all nutrients, as well as correct lighting to satisfy the plants' needs, the algae will still find a way to outcompete the plants and become a problem, even if just one missing nutrient is the only limiting factor.

Edited November 26, 2022 by Jungle Fan

[nabokovfan87]

You definitely want movement. Maybe an air stone or a few of them gives you that.

Interesting question.

I'd run the filter, I would totally add some shrimp too.

[JettsPapa]

I hate to disagree with replies above, but I have a moderately 5.5 gallon tank on my desk that doesn't have a filter or air movement.  The only thing on it that requires power is a light.  It's been running since June of last year and doing just fine.  I change one gallon of water every week to ten days.

Shrimp are thriving, and it currently also has seven juvenile endlers, though I'll almost certainly bring them home when I'm not at work over the holidays.  As a disclaimer, with heavier stocking I'm not sure it would work.

[Tanked]

My 10 gallon project tank has also been running sans filter for almost two years. Incorporating sand, bladder snails, plants and various forms of light, the only long term issue is the accumulation of snail detritus.  This past April, an air stone was added briefly to break up a heavy surface biofilm.  The film occurred about the same time that lights began to fail.