Shade and indicator plants

[Connswater]

Marcel recently mentioned Hygrophila polysperma as a useful indicator plant for NPK and trace elements. Barry James in his book - 1986 - recommended Hornwort for judging appropriate light levels. Dennerle used to recommend Hornwort for all new tanks to shade the tank and absorb excess nutrients. I increasingly find Frogbit demands too much NPK in the water column to be an effective indicator plant. But all floating plants can quickly impede the health of plants below them, even a light covering - say 50% of the surface - can reduce light intensity by at least 50%, and maybe 80% directly below - and I've found Rotala macrandra and, a carpet of Eleocharis, incompatible with Salvinia, Frogbit and Indian fern. Some stem plants, will also quickly drastically shade a tank, Limnophila sessiliflora is a prime example. But Brazillian pennywort will do the same, and of course, leave a lily uncontrolled in a tank and it will in due course be the only plant, Nymphoides hydrophylla Taiwan tries to dominate my tank regularly. And, yes of course in natural waters there is a competition for dominance and that involves monopolising the surface of a body of water. In my small tank currently Aponogeton boivinianus after a winter of dormancy, it lost all its leaves, is now determined to master the environment.

For a really easy maintenance tank: crypts, soil based substrate, low to medium light, without floating plants or indeed any stem plants, seems easy to balance, especially if low levels of CO2 are maintained with 24/7 injection.

But if we want varitey in texture, colour and shape and go for a high light, 25+ ppm CO2 injected tank what realistically are the best indicator plants and, are floating plants after the initial running-in stage, simply more bother than they are worth? Especially since, they demand heavy water column feeding.

For estimating light intensity I've found "injury" pearling works well but also Indian fern, if the latter produces O2 micro bubbles after around two hours of lights on, CO2 and light are about right for most non-shade plants.

For estimating if NPK and trace elements are adequate I find Ludwigia repens and Hygrophila polysperma works well and if they are a good colour and growing well, the level of fertiliser available is adequate, and the levels needed to keep them healthy and happy are not so high that algae may become problematic.

Duckweed is just a pain so to be avoided, Salvinia and Frogbit need too rich a water column, levels which if light is allowed to penetrate the water column will produce nuisance algae and Water Lettuce and Indian fern, both of the latter grow too large, so as floating plants, it seems Dennerle has a point, Hornwort is the best option. Yet I seem to be only able to get Ceratophyllum demersum which I find doesn't like warmer waters or softer water, submersum I used decades ago but I seem no longer able to find it.

 

[PARAGUAY]

Interesting post, I don't know own the exact reason but even when the Salvinia covers the entire surface Hygro.Polysperma still grows perfectly well and healthy. For the last few months I give a fraction of the AIO complete fertiliser after watching Josh Sim fertiliser video but Darrel, @dw1305 Darrel uses this method . No significant issues with my "easy plants" I do have the best water United Utilities soft from the lakes , kudos to hard water users

 

[Connswater]

Hygro.Polysperma

I find this is a very adaptable plant, it grows slowly, dark green under a canopy, in full sun, turns pink and grows fast.

Soft water is a real asset in the hobby.

My current view is, and I keep revising my thoughts in light of experience, is that many plants don't need anything like the water column levels of Nitrate in particular that keeps Salvinia and Frogbit healthy green and fast growing. Inidan fern and Hornwort are better plants for matching water column nutrition to rooted plants to avoid algae.

Green Aqua have just been to Lisbon, the Amano huge tank there is floating plant free - but has lilies - and modest levels of CO2 and what many of us would regard as nutritionally low water. But the plants are in essentially pots of nutrient rich compost.

 

[dw1305]

Hi all,

Interesting post, I don't know own the exact reason but even when the Salvinia covers the entire surface Hygro.Polysperma still grows perfectly well and healthy. For the last few months I give a fraction of the AIO complete fertiliser after watching Josh Sim fertiliser video but Darrel, @dw1305 Darrel uses this method . No significant issues with my "easy plants" I do have the best water United Utilities soft from the lakes , kudos to hard water users

I wonder if it is the soft water? Part of the reason I like Amazon Frogbit ( Limnobium laevigatum) is that it shows plasticity of growth in response to nutrient levels and will grow at low nutrient levels.

I know it is fine in harder water, but it maybe that nutrient deficiency occur at a higher base level of nutrients?

In the "Duckweed Index" it needs to be a "leaf green" floating, or emergent, plant to take CO2 availablity out of the equation, and one of the problems with Lesser Duckweed (Lemna minor) was that it wasn't happy in soft water, or with low nitrogen (N) levels.

I thought that Amazon Frogbit circumvented this, but I never tried with harder water with low nutrient levels.

Cheers Darrel

 

[Connswater]

Amazon Frogbit ( Limnobium laevigatum) is that it shows plasticity of growth

Absolutely.

But with my currently, relatively hard tank water, unless I feed it well it starts showing issues long before many of the submerged plants are in deficit.

I think a lot depends on what plants we are trying to grow below floating plants. Open water plants, basically need high light, the equivalent of open water in a tank is no floating plants and clean low nutrient water.

 

[Gill]

This will not grow for me in this tank, have tried it since I set the 1st scape. Just refuses to grow and stays stunted even with root tabs.

 

[Connswater]

root tabs

Frogbit or Hygrophila will not grow for you?

Frogbit in my experience really needs a rich water column, essentially at least EI levels. I think Darrel is right, in harder water it needs additional feeding of Nitrate and of course chelated Iron. It also doesn't like weir HOB filters, airs tones or a lot of surface movement, but then that goes for most floating plants, and lights set a bit higher. I found it grew well in conditions that favoured Cabomba, very soft still and very well lit waters (more than 1 watt of LED per litre) with a low pH, with Cabomba Aquatic I had to use a fair amount of CO2 and I did so 24/7 which of course meant a low pH water. Cabomba will flower in such conditions but maintaining such conditions is for me an unreasonable amount of work.

Root tabs would have to be leaching.

In very hard water it does not do well long-term, your water is hard I think, from the tap. If with my very hard tap water I blend 50/50 with rain water and add chelated Iron, don't agitate the water surface and keep water column Nitrate pushing 20 it grows very fast, still not as fast as Salvinia. It also does better, and certainly looks better, in a humid environment. Again harder to achieve than first imagined since cover glass brings its own set of issues.

In hard water with a cooler tank, Hornwort - demersum - seems the best option. Though, it is very brittle in very hard in water, water with a lot of calcium. In softer water with genuine tropical temperatures Indian fern is a good option, especially for fry protection. Indian fern will of course grow very large, but that at least means it is easy to remove. If you can find soft, and more tropical temperature tolerant Hornwort -submersum - it is ideal for higher temperatures and blended water. It is supposedly native in parts of the British Isles and Europe but I keep finding demersum for sale and in wild waters, about 30 years I had soft Hornwort but over thinned a tank and have not been able to source it since trying.

Interestingly, with soft water and warm bright light even without CO2 injection, a tank with only Indian fern can look very attractive, a friend did this many years ago with a fairly shallow tank and multiple domestic T8 fluorescent tubes. I'm not sure I fancy a tank with only Frogbit, I think given free rein in softer water it would however, ultimately, be the only plant in many tanks.

Hygrophila polysperma looks best in medium to high light. I find it very easy and does well in a Walstad tank with moderately hard water but it prefers as Marcel suggested sensible levels of nutrition and in very hard water does need chelated Iron. In my experience it stunts only if CO2 levels are inadequate or air operated filtration is being used with very hard water, the latter results, I think, in a loss of key trace elements, the science of this process, that is too complicated for me.

 

[Connswater]

will not grow for me in this tank, have tried it since I set the 1st scape. Just refuses to grow and stays stunted even with root tabs

Last photos of your tank looked good but if I recall pea gravel and air operated filtration.

 

[Gill]

Last photos of your tank looked good but if I recall pea gravel and air operated filtration.

Yeah thick pea gravel and UGF for main filtration. Airstone cause I always like them and use them in most tanks.
I did want a bubble wall along the whole back, but it came broke so didn't bother in the end. Have found tanks I've used the bubble wall have been some of the best growth tanks I have had.
Then a Tidal 110 and Tidal 75 + a 1600lph internal for polishing water. And now a 400lph UV which has made a big difference.
I went with Vallis cause stems are no luck for me so far. Elodea is growing well without root tabs. Wisteria is leggy, but to be expected.
I was dosing heavy with ferts before and the plants that grew crazy was guppy grass, but that is a weed of a plant.

Yes hard water does make it alot harder to grow stuff, but I'm happy to have found a medium that does well and will stick with it. I may try stems again

Makes sense why no swords will grow and hydrocoytles will not grow either. Whether they are rooted or floating. In the past though I have had great success with swords in Coventry water, just not the last few years.

 

[Gill]

Frogbit or Hygrophila will not grow for you?

Frogbit in my experience really needs a rich water column, essentially at least EI levels. I think Darrel is right, in harder water it needs additional feeding of Nitrate and of course chelated Iron.

Yeah frog it is a no go, but have always used it in past scales with air stones and hobs etc. it's the splashing if water ontop they don't like.

Pond water lettuce has done well for me in this tank though, so that's been good.