Holes in plant leaves

[madlan]

Hi all,

Just got back from a long weekend and several stem plants appear to be disintegrating!
Large sections of the leaves are transparent if not dissolved, I thought this was Co2 related but the drop checker is lime green. I'm dosing EI daily (all in one) and have reduced lighting to 8 hours and 2 x 36w T5s.

Suffering a diatom outbreak at the moment but probably due to being only a few weeks old.
The stems have grown extremely fast so maybe there's a nutrient deficiency? I can't see any snails in there...

 

[ceg4048]

...several stem plants appear to be disintegrating!
Large sections of the leaves are transparent if not dissolved, I thought this was Co2 related...

Yes, that is correct! Well done mate.

...but the drop checker is lime green..

Hey wait a minute...So what? The dropchecker is a test kit. When forced to choose between what the plants tell you and what a test kit tells you, which should you believe?

Cheers,

 

[madlan]

The plants were doing great for the first week but since they have almost doubled in size the above started.

I'm guessing their Co2 requirements have increased due to this? That would explain it. I've increased the Co2 and will post back results, thanks Clive

 

[ceg4048]

Yep, excellent deduction. An organism twice as big may require twice as much food. A flow barrier grown twice as big may require twice as much energy to penetrate.

Cheers,

 

[madlan]

Here's some photos of the leaves, I've increased Co2 (3 bps)

 

[ceg4048]

Yeah mate, assuming that this is not predatory (that second photo looks like someone has been munching) this is blockage induced CO2 starvation. Do you see in the first photo where there is a pattern of translucency which then transitions to a fissure/hole within the translucent area? That looks much more symptomatic than in the second photo, although it could have started out the same way and then some beast simply took advantage.

Do a really good trim because it looks a bit helter-skelter from that angle. That's actually one of the fringe benefits of good aquascaping technique. Things are kept nice and tidy, which helps reduce flow blockages and stagnation points.

Cheers,

 

[madlan]

I've seen one or two small pest snails, I think you're right in that they are being opportunistic. The picture was taken during a water change as I couldn't get a close up, although they have almost grown to the surface!

Co2 has been turned up a notch so hopefully all will be well again soon

 

[gmartins]

An organism twice as big may require twice as much food.
Cheers,

Hi Ceg, actually I believe it may even be greater than that because the relationship between biomass (weight) and size is a power relationship. Tipically it will be something like this.

biomass = a*size^b,
where a is a constant that varies among species and,
b will tend to 3.

And biomass is a much better predictor of individual requirements (e.g. energy) than size.

cheers,

GM

 

[ceg4048]

Hi mate,
A cubic relationship eh? There you go. Then the stress might be even worse than originally thought...

Cheers,

The picture was taken during a water change as I couldn't get a close up, although they have almost grown to the surface!

Which brings up another point in that leaves closer to the surface are also closer to the light, which means they are exposed to brighter light, which drives a higher uptake demand for CO2.

Cheers,

 

[niru]

An organism twice as big may require twice as much food.
Cheers,

Hi Ceg, actually I believe it may even be greater than that because the relationship between biomass (weight) and size is a power relationship. Tipically it will be something like this.

biomass = a*size^b,
where a is a constant that varies among species and,
b will tend to 3.

And biomass is a much better predictor of individual requirements (e.g. energy) than size.

cheers,

GM

I guess the cubic relationship holds true for "animals" who have full-bodied volumes. The "rounder" the animal, the better the relation since the size^3 comes is essentially the volume of the animal. The "a" in the relation is a fudge factor that accounts for, amongst loads of other bio-activity things, the fact that animals are never spheres .

I am not sure if one can use this same relation to plants (maybe bulby plants like some cactii could pass the test), because the "sphere encompassing a plant" contains a lot of free space, and for the mathematically inclined, theres enough fractality involved. So fractal 3-space dimension of a typical aquarium stem plant is much closer to 1 than either 2 or 3. Hence a better zeroth order approximation is a linear relation between biomass and size.

Just my 2c..

-niru

 

[gmartins]

Hi niru

Did some research on the subject and you may be right. I remembered this relationship from my uni classes but I did wrong to assume that plants and animals were alike.

According to this paper: http://www.pnas.org/content/98/5/2922.long
it's even lower: Lenght = Mass^1/4

In pratical terms, and considering the philosophy that it is better to have CO2 and nutrients slightly in excess, I think it may be safer to say, as Clive did above, that we should expect go get a proportional increase in plant requirments with increasing plant size.

cheers,

GM