# Biogenic Decalcifying Plants



## Endler Guy (Aug 19, 2007)

Hello,

I just read the Basics thread and the article offered therein. It touched on hard-water plants that use biogenic decalcification in order to get their carbon rather than having to get it from CO2. I don't want to add CO2 to my Endler tank because I'm new at this and I don't want to risk accidentally poisoning them. Is there a list of these plants somewhere? My water is hard and alkaline for the Endlers so I think this would be the best route for me right now. My vallis is a hard water plant and is doing great. It grew over a foot in three or four weeks. It may very well use this system to get its carbon. My Amazon Sword is not doing so well. 

If there is no such list anywhere, is there at least a list of plants that come from hard alkaline waters? I'm thinking they might be the "hard-to-kill" plants listed on the main site.

Thanks,


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## Bert H (Mar 2, 2004)

Val's one of them. Elodea also, as I recall. I'm sure folks will chime in with others.


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## HeyPK (Jan 23, 2004)

When it comes to competing for CO2, even within the group that does biogenic decalcification, there are differences. Eigeria densa, Najas species, Elodea species are near the top. Below them come Vallisneria and Ceratophyllum. Third, are the larger swords, like E. bleheri and E. uruguayensis. The ones at the top in bright light can remove so much CO2 that the pH can go up to 9 or 10, and that is lethal for many fish. If you have a tank in the sun with a lot of Najas, Eigeria,or Elodea, you should watch the pH daily and be prepared to take steps to keep it around 8 or lower.


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## Endler Guy (Aug 19, 2007)

Thanks Everybody! I'll try those and watch the pH.


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## hoppycalif (Apr 7, 2005)

CO2 is used by a huge number of people, and only rarely does someone harm their fish with it. It isn't hard to do safely. And, then you have a much larger selection of plants to chose from. I have a few endlers in my 45 gallon tank, with pressurized CO2, and they are doing extremely well. Even when I was running high CO2, and many of the fish were staying in the upper third of the tank, the endlers never showed any effect at all.


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## rs79 (Dec 7, 2004)

The other thing about biogenic decalcification is it's ugly. It deposits carbonate on the laeves of the plants.

Having said that some crypts are from pretty hard water. Ciliata and pontiderifolia come to mind right away. PON grows on limestone beds while CIL can be found in brackish water.


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## Robert Hudson (Feb 5, 2004)

biogenic decalcification is not something you really want to encourage. It causes very large pH swings


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## Endler Guy (Aug 19, 2007)

Thanks for your concern. I have a NPT so I don't have enough lighting to get huge pH swings. I was very new when I made the original post and thought that I'd need CO2 to get any significant growth from non-BD plants. Now though, I know differently. Even my hygro grows pretty fast with no CO2. The only ones that grow slowly are my crypts and two types of bacopa. The bacopa in another tank grows well, however. It could be allelopathy at work since I have sagittaria growing well in my 55 while it doesn't seem to grow in the 10 where my bacopas are doing well. I've discovered that my swords need iron fertilization. Since Ive been adding micros, they've been doing well too.


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## Edward (May 25, 2004)

You can not poison your fish if you set up CO2 to 1 - 2 bubbles per second and have some water surface movement.


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