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16 dKH Discus?

Jose

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What do you guys think? Is it possible to keep discus in 16 degrees KH water? Has anyone done it? If youve kept it in hard water can you say how hard (KH and/or GH). They would probably be UK bred. It would also be a planted tank. Im really looking for some evidence.
 

drodgers

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16° is not to bad its only moderate hard. I've been keeping fish at 28° hard water they seem to adapt well and as plug the stable water is better in the long run.
I think Discus refuse to breed unless you provide them a acidic home.
 

Jose

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16° is not to bad its only moderate hard. I've been keeping fish at 28° hard water they seem to adapt well and as plug the stable water is better in the long run.
I think Discus refuse to breed unless you provide them a acidic home.

Thanks for the feedback drodgers. I believe 16 KH is saturated water with carbonates from CaCO3. Thats as high as it gets unless the source of carbonates is something else than limestone. So it is very hard water. Dont get confused with different ways of measuring hardness and different degrees.
Also Im not looking to breed them just keep them.
 

dw1305

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Hi all,
I believe 16 KH is saturated water with carbonates from CaCO3.
It is, at atmospheric pressure 16dKH "water" is fully saturated with CaCO3, and the pH will be somewhere around pH7.8 (it will depend upon how oxygenated the water is).

This is partially why pH needs some interpretation as a measurement, and is only really useful with some indication of the carbonate buffering in a system.

cheers Darrel
 

Jose

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Yeap. I honestly dont think anyone has kept discus in the long run in this kind of water. By the way Darrel do you know GH of your tap water. Its probably the same as mine.
 

Jose

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So it seems there is no limit for hardness for tank bred discus? Mmmm Im a bit suspicious. Ive been in discus forums and they tend to recommend RO water.
 

drodgers

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I've had great success keeping soft water fish in my liquid cement its seems the stability is more important.
My latest addition to a new setup is Electric Blue Rams ,I've been told they are too delicate for hard water but they seem to be flourishing .
 

dw1305

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Hi all,
....By the way Darrel do you know GH of your tap water. Its probably the same as mine.
I do Jose, you can work it out from the figures the water company publishes <http://www.wessexwater.co.uk/customers/water-quality/waterhardness.aspx?pc=SN13 9AR>.

I have to make the assumption that the magnesium content is negligible, as the water company doesn't provide separate values for magnesium, but this is a fair assumption based on geology (aquifers are Jurassic age limestones).

One millimole of calcium per litre of water corresponds to a hardness of 100 ppm or 5.61 dGH, since the molar mass of calcium carbonate is 100g/mol. (Ca has a RAM of 40, C = 12 and O = 16, CaCO3 = 40 + 12 + 48(16 x 3) = 100).

100g in 1 litre is a molar solution of calcium carbonate (40% Ca), and 0.1g per litre a milli-molar solution.

1 dH is "One degree German" and defined as 10 milligrams of calcium oxide (CaO) per litre of water. The RMM of CaO is 56 (40 + 16) and it is 71.4% Ca.

This is equivalent to 17.85 milligrams of calcium carbonate per litre of water, or 17.85 ppm. (71.4/40 = 1.785 and 10 x 1.785 = 17.85)

2014
Calcium (milligrams per litre) 131.6 (329 x 40%)
Calcium carbonate (milligrams per litre) 329
Degrees German (ºdH)18.424 (18.24 x 17.85 = 329)

These were the corresponding figures in 2009.
Calcium (milligrams per litre) 119 (298 x 40% = 119)
Calcium carbonate (milligrams per litre) 298
Degrees German (ºdH) 16.7 (16.7 x 17.85 = 298)

cheers Darrel
 
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