Nitrate limitation and substrate

[JoshP12]

So, this happened by accident ... I was unhappy with the right side of my tank (sand bed), and I wanted more plants; so I planted my trimmings in the sand ... I like soil for obvious reasons, but I wanted to see if there was a difference (and this way I didn’t have to rip it all up ... long term goal).

Anyways, I noticed my rotala rotundifolia in the sand is strikingly red compared to the soil tips. I did notice that as I plant the tips, they get a deep red intermediate colour, then once they root (I presume), they get back to green.

My recent dosing and water change is as follows (been recovering the tank so probably changing more water than I “plan”, but I kind of like it).

Daily dose of ei micro/macro

Water change 60, 2x a week.

So, the big question: is this coincidence? Does colour change as a plant roots? Does substrate nutrient accessibility affect “how easily” we get colouring?

I am just curious!

Cheers,
Josh

Note those soil sprinkles on the sand are just sprinkles; it isn’t mixed.

 

[jaypeecee]

Hi @JoshP12

Where does nitrate fit into this? You mention 'nitrate' in the thread title but not in the text or am I mistaken?

BTW, good to see you around again.

JPC

 

[Sammy Islam]

Hi @JoshP12

Where does nitrate fit into this? You mention 'nitrate' in the thread title but not in the text or am I mistaken?

BTW, good to see you around again.

JPC

I think he means the rotala planted in the soil substrate would have access to more nitrate and therefore more green than the rotala planted in the sand. The theory being the sand has no/less ferts than the soil so the limitation has turned the rotala more red. But not sure how this would happen seeing as there EI levels of ferts in the water column.

 

[Witcher]

But not sure how this would happen seeing as there EI levels of ferts in the water column

I think the only possibility is that other plants in @JoshP12 tank are N hungry and nitrates are quickly depleted. But still think it's very unusual and they must be extremely hungry in this case. Plus strong light may help with the coloration.

 

[jaypeecee]

But not sure how this would happen seeing as there EI levels of ferts in the water column.

Hi @Sammy Islam

And that's why I'm confused.

JPC

 

[JoshP12]

Hi @JoshP12

Where does nitrate fit into this? You mention 'nitrate' in the thread title but not in the text or am I mistaken?

BTW, good to see you around again.

JPC

Thanks JPC! I am around, just lurking. I finally have a post to make that isn't that my tank is a disaster and I am losing my mind .

I think the only possibility is that other plants in @JoshP12 tank are N hungry and nitrates are quickly depleted. But still think it's very unusual and they must be extremely hungry in this case. Plus strong light may help with the coloration.

The irony is that the plants that are redder are surrounded by less plants than the greener ones.

My light is pretty low I think - running 2x AI primes at 40% ... If I had to make a terrible guess, I would say that 30% (some channels are much lower than 40%of 86 mmol with some overlap, so x2 rounded down by a bit? maybe 50 PAR at most ... trying to get ahold of a meter .

Hi @Sammy Islam

And that's why I'm confused.

JPC

and

The theory being the sand has no/less ferts than the soil so the limitation has turned the rotala more red. But not sure how this would happen seeing as there EI levels of ferts in the water column.

Well, I was reading some of Dennis Wong's stuff on nitrate limitation and he always says the water column tests ... and reads several variants of ppms.

I would say with 2x 60's a week for WC, I am probably at 10's for Nitrate at most. So I wouldn't be surprised if maybe that is inducing some color ... but the I wonder if roots and nutrition in the substrate affects how low you have to deplete the water column of nitrates to induce color. It makes sense, but then how can people get coloring with soils like ADA which has so much nitrogen ... might be a way to get coloring without reducing your Water Column dose

Josh

 

[Ray]

Thanks JPC! I am around, just lurking. I finally have a post to make that isn't that my tank is a disaster and I am losing my mind .

Those crypts and your rotola seem to be doing very well indeed .

The only other explanation I can conceive other than nitrates is light reflection (e.g. off sides or sand) or plant position boosting light dose to some plants - but squinting at your photos that looks like a long shot.

 

[JoshP12]

Those crypts and your rotola seem to be doing very well indeed .

The only other explanation I can conceive other than nitrates is light reflection (e.g. off sides or sand) or plant position boosting light dose to some plants - but squinting at your photos that looks like a long shot.

thanks 😊.

I’m starting to think that my conjecture that

Nitrate in Water column that induces coloring from nitrate limitation = some function of nitrate in water column - some function on nitrate availability in substrate

... Is true. This would explain why Wong mentions 0p ppm testable giving deeper colours. I can assure you that I have more than 0 ppm.

Every single stem that I plant, regardless of substrate, gets intensely coloured and then as it grows (and presumably roots) it becomes less coloured in the following leaves. I am watching my sand rotala sand they have not turned greener ... yet.

At lights on, I will snag a picture of a leaf doing what I described and post it.

Josh

 

[JoshP12]

My pictures were no good @Ray; I'll try again another day. But just interesting ... those same sand rotalas (some of them) turned green ... it must be rooted.

 

[rebel]

What happens to the tips as they approach the top of the tank? I find that more light will make them orange as well. You can simply increase your light by 10% and CO2 by 10% and wait.

 

[JoshP12]

What happens to the tips as they approach the top of the tank? I find that more light will make them orange as well. You can simply increase your light by 10% and CO2 by 10% and wait.

I have been trimming them aggressively, so far nothing has got to the top top, but I did notice that orangey. it fooled me thinking it was a deficiency but glad to hear it’s consistent with what you saw.

Josh