# Hair grass not growing



## Jamie McGrath (4 Jan 2018)

This is my dwarf hair grass, it’s been planted for about six months. It has spred a bit since planting but it is still very patchy and after a while the new shoots go brown and then die. I inject co2 and fertilise with aquarium plant food fertiliser. I have two 58w Arcadia plant grow T5 lamps about 65cm from the substrate. The water is at 23c I do 50% water change every week. There is good flow throughout the tank. Can someone help or give me advise I’m getting very frustrated!


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## Edvet (4 Jan 2018)

Describe your CO2 in detail please. Looks like a CO2 problem (amount, distribution).
Other plants are doing?.........


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## kadoxu (4 Jan 2018)

What @Edvet said + what kind of substrate do you have?


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## Nigel95 (4 Jan 2018)

DHG likes a good aqua soil in combination with lots of light, water column dosing and co2.


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## Jamie McGrath (4 Jan 2018)

Edvet said:


> Describe your CO2 in detail please. Looks like a CO2 problem (amount, distribution).
> Other plants are doing?.........



Thanks for your reply, co2 is about 1bps , the diffuser is directly below a power head and the filter spray bar, which I believe provides good distribution. The drop checker is light green at lights on , the lights are on from 15:00 to 23:00 . App other plants are doing well but they are mostly stem plants and a few Amazon swords.


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## Jamie McGrath (4 Jan 2018)

kadoxu said:


> What @Edvet said + what kind of substrate do you have?



Hi , I have three large bags of tropica growth substrate capped with sand


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## Edvet (5 Jan 2018)

1 bps sounds low. WHen does it start, when and how long are the lights on?
Spraybar sounds good but a full tank shot to see the situation would help.
Do you have access to a pH pen or other electronic pH device? A pH profile will tell more.


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## PARAGUAY (5 Jan 2018)

First time I planted it didn’t do well . I think they require more CO2 than many plants and good water column dosing,if your happy with distribution you could try increasing both a bit and see how it goes.Interestingly Ceg should answered a query about two different plants together in the aquarium one doing well with the CO2 and fertiliser regime one doing poorly.Some plants require more CO2 than others.


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## Edvet (5 Jan 2018)

I am guessing in a round leaf the surface to volume ratio is different from a flat leaf which makes CO2 uptake harder.


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## ceg4048 (5 Jan 2018)

There are a few reasons why no two plants require the same amount of CO2. I'm not sure why people expect that all plants must behave the same way and have exactly the same characteristics and requirements. Each species has strengths and weaknesses. Plants produce an enzyme called Rubisco. The job of Rubisco is to attract, hold and transport CO2 molecules in order to convert the CO2 into sugar.

There is one fundamental "flaw" in the characteristic of Rubisco, however, and that is Rubisco has a difficult time distinguishing CO2 from O2. 
For every 4 molecules Rubisco collects, only 3 are CO2. So when Rubisco dumps it's cargo into the reaction center only those 3 CO2 molecules are used. The Oxygen molecule does nothing, so the sugar production operates at 75% efficiency at best case. These Oxygen molecules causes a LOT of downstream problems because the plants has to waste more energy finding a way to incorporate them. 

This wasteful recycling of Oxygen in the reaction center that specifically requires CO2 is referred to as "Photorespiration".  
Photorespiration is especially wasteful because the net result of the process is the release of CO2, so it undoes the job of Rubisco.
The reaction center in which CO2 is converted to sugar is called The Calvin Cycle.

So now, there are two ways in which precious CO2 is lost by the plant: a) ordinary respiration which occurs when the plant consumes the sugar it produced and,  b) inefficiency of sugar production via photorespiration.

There is something called the CO2 compensation point where the uptake of CO2 through the photosynthetic pathways (Rubisco) is exactly matched by the loss of CO2 through respiration and photorespiration. At this point, there is zero growth and if the carbon loss is greater than the carbon uptake, the plant dies.

Each plant has it's own compensation point. It's carbon uptake ability will be limited by various factors, as mentioned, leaf morphology, not just size and geometry, but also cuticle thickness, which is an obstacle to CO2 and Oxygen uptake, Rubisco  and chlorophyll concentrations within the leaf as well as other photosynthetic chemical efficiency.

There are so many variables which affect how well a plant can gather and assimilate CO2. One size cannot fit all.

As Edvert points out, the partial pressure of CO2 may need to be increased, so an injection rate increase can be attempted. It's not clear how the spraybar is oriented and it may be that the flow is not reaching the substrate effectively. More data is needed to analyze the cause of CO2 deficiency.

Cheers,


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## zozo (5 Jan 2018)

I experience this plant rather extremely hard to kill.  Got it in the low tech on inert gravel for far over a year now. (So in how far this gravel is still inert i doubt) But it lives and it also spreads runners, very slow in this case but it does. The time i had it in the high tech it grew on inert Akadama, very lush and dense. But only dense if it is trimmed regularly. It realy is a gras, trim it back to about 10mm and it starts running and spreading, if you don't it puts more energy in growing erect and runs less.

Funny is in the low tech it has minimal co2 a tad less light, but it's clean as a babies behind. In the high tech it grew relatively shaded under the floaters but it still was a staghorn and or BBA magnet first class. Especialy when not trimmed, older leaves are rather very susceptible to grow algae than it's running into a visious cirkle beeing suffacated under the stag. Looking at the pics, especialy the last one, i think i see stag and it looks like it's rarely trimmed. 

That the down side of having a carpet, you have to trim it back at the moment it looks at it's best. And thats a difficult decision. But if you don't you run into issues. After trimming it looks a bit awfull again for a few weeks. The splendid pictures of lush carpets you usualy see around are practicaly snapshots of the moment. Ususaly short before it needs that rigorous trim.. Don't run away with the idea it looks for ever like the way it's presented in pictures. A nice carpet generaly looks a longer periode awfull than it looks nice. Bottom line, carpeting is snapshot show off material..


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## Johnn (5 Jan 2018)

1 bps is definatley far too low for a well planted tank with a 60cm height. What size is the tank?
I've ran around 5bps in a 20 litre aquarium and had amazing results, the flow was very strong which allowed fish to survive but probably gassed off a lot of the co2
How strong is the flow down the bottom?
If lighting/parameters are all good, i suggest you crank up the co2, and water flow near the bottom.
Then add more frets if needed

https://www.fishlore.com/aquariumfishforum/media/3ft-planted-wall-tank.233732/


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## HiNtZ (6 Jan 2018)

IMO - CO2. The black algae on it alone should make this evident. Combined with poor flow and you will see results like these.


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