Re: hard water

[Paul Krombholz <krombhol at teclink_net>]

    * From: "pieter cool" <pieter_cool at esat.kuleuven.ac.be>
> .....Might there be any problems with using very hard (Kh and Gh 
> about 20 ) tapwater for a planted aquarium?
> For the moment I'm using RO water mixed with tapwater to get a 
> hardness of 10 Kh. Because this is a lot of work I would like to 
> skip the RO water.
> One of the plants in my thank that I think migth not be so happy 
> with this hard water is hemianthus micranthemoides. Another one is 
> cryptocoryne pontederifolia.
> Am I right about this or not?
> Are there any other bad consequences like a higher pH (above 7 )?

Cryptocoryne pontederiifolia grows well, according to Kasselmann, in 
soft to medium hard water, weakly acidic to neutral.   Kasselmann 
also says that Hemianthus micranthemoides does equally well in soft 
or very hard water.  Just make sure that both species get a little 
iron supplement now and then.  Both species respond well to 
supplemental CO2, and so I would keep the pH from getting higher than 
7 by adding CO2.  I find that pontederiifolia likes soil with a lot 
of organic matter.  50% peat plus topsoil is good.
--
Paul Krombholz