Plant filtration and Nitrates

[FreshyFresh]

I've got a big pothos plant in a Marina breeder box, hanging off the back of my oscar's 75g tank. I've had it about 9 months now. I haven't noticed any nitrate creep reduction with this plant. No way to read nitrates that accurately with the API master test kit. My tube never exceeds a pale/light orange on day 7. ~20ppm? Day 7 = fin-level WC.

I also have some pothos growing out of my goldfish's 55g. I expose the roots to air during WWCs, so this plant is growing very slowly.

 

[celebrist]

beautiful setups!

 

[skjl47]

Hello; I have followed this thread with interest. I keep live aquatic plants in most of my tanks and have for years. I was never sure of the level of benefit from the plants but have heard for a long time that plants have some benefits for water quality.

From this thread some things seem apparent, but let me check. To some degree it is the mass of the live plant with regard for the uptake of things such as nitrates and ammonia.

So I should do a bit more pruning of ragged plants and for sure remove dead or dislodged leaves??

While the benefit of plants is hard to determine it is safe to say that live plants do have some benefit??

I should look into emergent plants for additional benefits as my aquatic plants tend to grow slowly??

Which emergent plants smell good? Not thinking of the flowering part. I ask because some garden plants do have a strong smell.

At any rate I will keep using live plants regardless of any nitrate removal because I like them. I have been in a planted tank phase for some time now with few fish, at least compared to the number of fish I use to stuff into a tank.

 

[Cohazard]

Thanks for the responses everybody, I really appreciate it, especially since there's a huge thread about this subject, but it's kind of a beast to get through when you're short on time.

One last questions, what is the medium you grow the emersed plants in? thank you

 

[Coryloach]

I use hydroton clay pebbles only or a combo of clay pebbles at the bottom, a layer of garden soil and small gravel to cap it.

 

[Drx6x]

depends on the plants / how you want to do it just started my setup. got 2 cuttings from a lady thats had the plant for 50 years.

 

[duanes]

I find neither pothos or papyrus (umbrella palm) need a media, I have stuck papyrus in pots of old aquarium gravel when it was appropriate for, and wanted to sink it in large tanks. But in many cases the roots over grow the pots.
By the way, if you get papyrus, buying one is sufficient to start, because it multiplies very rapidly. stems will droop, and when the leaf top touches the waters surface, that part sends out roots, starting a new plant.


By the way papyrus can also be grow out of water in pots. I would bring my pond papyrus plants in for the winter, and had too many for tanks after a while, but after draining the pots would overwinter just like any house plant.

 

[hart24601]

A lot a great advise in this thread! The atmospheric CO2 points are great. Being in an agricultural area we deal with nitrates and other organics in the tap and before switching to RO/DI water I used quite a few plant systems. I still use them now even.

I have pothos and peace lily currently growing in my external overflows, no substrate just in slotted baskets (they do great) but I keep them mostly for looks. With a large bioload I have found you need a lot of pothos and PL to keep up as they don't grow terribly fast. I am sure some will disagree, but that is my experience. If you have a large area of them then they can do it and of course if you have a HUGE pothos vine that helps, but mass of plant vs mass of plant there are better option. That being said if you are space limited pothos can be fantastic as you can have them vine near windows and not need a large footprint in the system.

The best plant and setup I have used is water lettuce. You just need enough light for it, but you can see it grow daily and in a refugium style setup you can export (aka scoop out) a lot each week. Remember the majority of nitrogenous waste removed will be in the plant's tissue so if your tank produces 1ppm nitrate a day then you need (almost) enough growth to "lock" those compounds and export as desired.

Few papers here, 1st is looking at Water Hyacinth, Water Lettuce and Vetiver Grass as exports. The grass gets a bit too big for most. I have used hyacinth and prefer managing WL. WL also has lower N and P requirements so it will grow better once those levels start getting low. Just have to use a lot of light IMO but it grows insanely fast.

http://article.sapub.org/10.5923.j.re.20120205.04.html

Here are a couple other papers using water lettuce, these are recently published, seems to be getting more attention.

http://www.isaet.org/images/extraimages/P315027.pdf

https://www.deepdyve.com/lp/elsevie...w-rubber-processing-industry-using-NJwK6JcE0v

http://www.iosrjournals.org/iosr-jmce/papers/vol13-issue2/Version-1/Q13020198101.pdf

 

[Coryloach]

I see hart24601 says Peace Lilies don't grow fast...I think they grow extremely fast...The reason I grow mine in hydroton clay pebbles is because I have hard water...Hard water inhibits micronutrients like iron and majority of micronutrients in fact. But iron is my problem and clay pebbles are rich in it...

Iron is a micronutrient(micro means low demand) but for most plants iron is needed in higher amounts than rest of the micro nutrients and is almost as important as macros like nitrate, ammonia, potassium, phosphate, etc... So if your emersed plants are growing slow they are nutrient or light limited.....But given a very good amount of light, providing emersed plants have unlimited CO2, think nutrients. If your water is hard, you need to dose micronutrients that are stable in hard water(the type of chelator matters)...and if your fish tank provides too little nitrogen, then extra macros in the form of nitrate, potassium and even phosphate(though the latter is rare because its abundant in fish tanks) will be needed additonally to keep the plant "good looking"..

Chemical fertilisers dosed to an aquarium are not harmful to fish because they do not have organic molecules attached unlike the naturally produced ones in the tank....So don't shy away of keeping your plants happy. Happy plants will keep your tank happy...

And hey,....don't forget that when your plant's leaves start deteriorating it means you have achieved your goal of depleting the tank water of a particular .


A last general rule for those that haven't kept plants....Macro nutrient deficiency affects old leaves. Micro nutrients affect new growth...So depending on where the necrosis/chlorosis/discoloration is, think which type of nutrients are involved....google what are macros and what are micros if you don't already know....but the whole planet's survival is dependant on plants so all of us should know the basics and importants of plant

 

[hart24601]

I found a few pics. Early March when I added plants to the overflow. There is a peace lilly, and couple small varieties of pothos. The lilly was larger than the pothos mass wise. Lighting is 2 kessil 160we plus some indirect sun - lots of light! (I recently took one kessil offline and movies to a dedicated water lettuce refugium). Look at that water lettuce on the surface!





Now here is the same system 9.5 months later. Some big growth! Not as much from the peace lilly. These lights are strong enough the leaves burn directly under them (not the lettuce of course), but other than that no trimming. A lot of growth! Clearly I made some other changes too such as removing plants from the inside.



However this photo is how much water lettuce I would remove from that tanks surface every 7-10 days!! No joke - just taking the smaller plants. The biomass export is insane. Keep on mind this system get a 15% daily RO/DI drip too!



Now I habe moved to a dedicated WL refugium under the 180g tank next to this one (plumbed together) but you can see how plants can grow crazy fast and be a wonderful export mechanism even on a system that gets fairly large daily water changes with pure RO/DI water.