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Black stems

TOO

TOO

Member
Joined
4 Jul 2012
Messages
406
Location
Aarhus, Denmark
Hi,

After having pruned my R. rotundifolia a good number of times I have noticed the old stems going increasingly black. Is this common and how can it be dealt with? Nutrient issue?

One option of course would be to uproot the old plants and plant the cut-offs, but then I would loose the nice bushy appearance (and create a mess in the tank).

Another option would be to cut the stems just above the surface, but perhaps this is too hard on the plant? (also it would take a good deal of time before the plants start to fill out again).

I hope to hear some experience and advice.

Thomas
 
Blackening of stems and leaves is caused by poor CO2. You need therefore to either increase the injection rate or revise your flow/distribution if this is a CO2 enriched tank. If this is a non-enriched tank then the only option is to reduce the lighting intensity.

Cheers,
 
Nothing to worry about, Stem plants have so-called nodes which go leaves or new branches of the stems. The distance between two nodes is called internode when you cut the plant at the internode, is normal to die this section to the nearest node. Area turns black and dies.If you want to do this kind of bush just Cut the group to the desired height and from there you will grow new shoots that will thicken. The group will be compact and will look like a bush:)
 
Thanks.

ceg4048 said:
Blackening of stems and leaves is caused by poor CO2. You need therefore to either increase the injection rate or revise your flow/distribution if this is a CO2 enriched tank.
Click to expand...

This is CO2 enriched but I have recently upgraded to a new system because drop checker stays dark green. Hopefully this will help.

I am struggling a bit with circulation. Have a pump rated at 900 l/h for a 84l tank, so in theory okay. But still it seems that some areas do not get enough CO2. I am thinking perhaps this is because of the rather large surface. This is a shallow tank 75x45x25. I am using the ADA jet pipe as outflow.

Thomas
 
Hi,
CO2 is a very tricky business. A dark green DC is never a good sign, especially if the lighting is high. Even if you improve your CO2 five days ago, it will like be a week or two more before you see any benefit - assuming you fixed all the problems (which you can't tell until the plants either live or die). Temporarily reducing the light intensity will help a LOT.

I don't really know much about the jet pipe. Is this what it looks like for an outflow?
1_0a.jpg


If so this doesn't really look like a good idea at all for flow/distribution. Now, if you could turn it horizontally and mount it on the back wall that might work.

Cheers,
 
Thanks a lot again. Good to know that patience is needed.

It is the version called power pipe you can see at the last part of this link:

NATURE AQUARIUM GOODS » Filtration System - Metal Jet Pipe P (Outflow) / Metal Jet Pipe V (Inflow) ||| ADA Nature Aquarium - Aqua Design Amano Co., Ltd

Actually, it creates a lot of rippling on the surface near the outflow and the plants at the other end immediately facing it sway quite strongly. But is a bit as if the flow then dissipates and has difficulty reaching, especially, the back third of the tank (where most of the plants are). The outflow is placed close to the front pane. Perhaps it would be better to centralize it.

Thomas
 
Hi Thomas,
Yeah, this doesn't inspire confidence at all mate. If you have an old spraybar hanging around you might want to hook it up on the back wall with the holes facing forward, just for a comparison. Sorry to be so negative but I'm very particular about flow patterns and distribution. It can make or break you. As you mention moving it around to a more logical position might help.

Cheers,
 
i have just been having this very same fight for the last few weeks . as ceg says , flow / distribution is critical . even if you arew injecting plenty of co2 , if it isnt being distributed efficiently you will find some areas do well , whilst others melt away and die .

a few of the things i learned whilst battling co2 issues are

1) co2 is a pig to get right
2) without even flow / distribution its a battle you wont win
3) drop checkers are ok as a rough guide , but your plants will be your true indicator . lime green drop checkers is a good starting point to go for , but expect to have to change it if the plants are not happy .
4) make small increases to your co2 injection rate and observe your fish ( assuming you have fish) .

in the end what worked for me when i had a day i would be at home all day , increase co2 to the point that the fish were gasping at the surface , and then dial it back as little as i could get away with until fish were comfortable again . you need to be careful doing this though . for me it was a case of when they started gasping , dial the co2 back a little , then aim the spraybar above the surface and really agitate it . once the fish settled lower spraybar again and monitor . once the gas built up again , if the fish were still stressed , i would repeat the cycle . if no stress id inch the gas up a little again etc . took a while to get the balance , but in the end it got my tank going .
 
I read the posts and wonder if you really talk about Rota rotundifolia That's weed grows where you put it and any conditions so this is one of the easiest plants to grow. I've growing it for years in aquariums without fertilizers, carbon dioxide, and even without filtration. I grow it even without water. Better show an image to see it this black Rotala. I doubt that could anyone fail to grow this plant
 
anasarka said:
I read the posts and wonder if you really talk about Rota rotundifolia That's weed grows where you put it and any conditions so this is one of the easiest plants to grow. I've growing it for years in aquariums without fertilizers, carbon dioxide, and even without filtration. I grow it even without water. Better show an image to see it this black Rotala. I doubt that could anyone fail to grow this plant
Click to expand...

I didn't say the plant was not growing. It grows well and has probably been pruned back ten times.

Thomas
 
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