Do plants help seed a tank?

[Dawn]

I recently bought my 4th tank.  It's a 29 gallon that was set up 7/15 evening.  The plan is a well planted tank with Guppies!! 

I've already put in my XL sponge filter from by 60 gallon to get things going.  The 60 is an mbuna tank with 20 older juvies in it.  It also has a Marineland 350.  But I intentionally overfeed a bit to get these fish to grow.  With everything running optimally, I can do a 50% weekly water change and keep the Nitrate to max 40 at water change time.  But I'm worried that taking the sponge filter out will have a negative impact on this tank.

I've already added 2 Amazon Sword from my LFS to the 29.  But I also have hornwort in my 45 gallon.  If I put the hornwort in the new tank, will that help get things going?  I also added some cholla wood from an established tank.  I ordered a Marineland 200 for this tank but I won't have that until 7/18.  If I add the plants from an established tank and remove the sponge filter once I get the HOB, will that be enough to seed the tank?

[Mr. Ed's Aquatics]

All surfaces of a cycled tank containe the helpful bacteria including plants. If the amount of hornwort is similar in surface area size of the sponge filter I would think you'd be fine. You can also use a few handfuls of gravel from a cycled tank. If you don't want to add it to the substrate, keep it in a cup or bowl on top of the substrate until your new tank is cycled then return it to the tank it came from. 

[Wmarian]

I agree plant surface will be a little help if taken from a well eatablished tank. Plants primarily great at using up the nitrates though, not with helping with ammonia and nitrite end of the cycle. IMO  the twoplants will not be sufficent to help with the nitrogen in the tank or carry enough additional beneficial bacteria to replace the sponge filter while the HOB starts up. Suggestions: I agree more plants, especially floaters or things like water sprite and hornwort like you said. Maybe get extra  sponges or foam that you zip tie around your sponge filters or just leave in tank or something, and then use those sponges to hot rod your new filter. Also, many people say Fritz 7 startup juice ensures a safe quick startup. I haven't had to test that hypothesis however (yet) good luck, keep us informed.  

Edited July 19, 2020 by Wmarian
Autocorrect correct and adding suggestion

[dublicious]

14 hours ago, Wmarian said:

Plants primarily great at using up the nitrates though, not with helping with ammonia and nitrite end of the cycle.

Just a small correction: In her book, Diana Walstad discusses ammonia/nitrite/nitrate preference in plants.

On ammonia: "Most aquatic plants studied, when presented with a choice between ammonium and nitrates as their nitrogen source, take up ammonium exclusively. Only when ammonium is unavailable, do plants take up nitrates."

On nitrite: "Although plantes definitely can use nitrite as a nitrogen source, the pertinent question for aquarium hobbyists is- Do organic plants remove the toxic nitrite in preference to the non-toxic nitrate? No definitive answer to this question in the scientific literature is currently available."

So plants will consume both chemicals (clearly preferring ammonia), but we don't dose them because our fish wouldn't like that very much! In fact, ammonium sulfate is commonly used as a soil fertilizer! So they will contribute on some level to ammonia/nitrite reduction in the tank.

The size (or surface area) of the plant probably determines how much beneficial bacteria they'll bring along though.

Edited July 17, 2020 by dublicious

[Wmarian]

That's really interesting! Looking online it seems like ammonium is non Toxic, while ammonia  is toxic, and that the balance between the two is impacted by PH and temperature (low PH tending to convert ammonia towards ammonium, the ionized form of ammonia).* Does Walstad consider the two interchangeable for her purpose in her discussion of the ecology of the tank? Are plants likely to take up ammonia as much as ammonium?

Following up on the original question, I think it's likely that ammonia will be the concern for the new fishies.  And regardless, I don't think the amount of plants described will make enough of an impact on any form of nitrogen in the tank to ensure fish safety. I think Walstad would agree with heavy planting to address this.

Your quote of Walstad raises an interesting question  regarding nitrites. I am going to explore if there is any more recent research regarding plant uptake of nitrites...but it seems odd that nitrites aren't part of fertilizers if so (well, toxicity level would be one reason). Also, (when closely monitored with testing) the bacteria appear to convert nitrites to nitrates, rather than nitrates being taken up by the plants prior to conversion. But maybe some portion is taken up by the plants?

*https://support.hach.com/app/answers/answer_view/a_id/1011356/~/ammonia-vs.-ammonium-–-what-is-the-difference-between-these-forms-of-nitrogen%3F-

Edited July 17, 2020 by Wmarian
Additinal question added

[dublicious]

5 hours ago, Wmarian said:

Does Walstad consider the two interchangeable for her purpose in her discussion of the ecology of the tank? Are plants likely to take up ammonia as much as ammonium?

She refers only to ammonium, and doesn't say whether they take up "ammonia" as readily. However, I don't think it matters, and here's why: 

As you noted, pH (along with temperature, and apparently to a lesser degree other factors) determines the ratio of unionized ammonia to ionized ammonium in the water. This is why we consider ammonia "less toxic" when the pH is lower. When a plant consumes ammonium, if the ratio remains the same, it means more ammonia is ionized to make ammonium, therefore reducing the ammonia levels in the water. I'm open to the idea that I may be oversimplifying as I'm sure there's a lot of other interesting chemistry happening that we don't really measure/care about as much.

I agree that the amount of plants involved will determine their contribution to nitrogen removal (whether ammonia/ammonium or nitrate). To keep referencing Walstad (her book was a recent read 😆) the reason for minimal filtration in a "Walstad" tank is that plants and beneficial bacteria are believed to be in direct competition for ammonia/ammonium. If you have a heavily planted tank with reasonable stocking, the plants would be happier consuming the ammonia directly.