[APD] Re: too much iron in water?

[Bill Wichers <billw at waveform_net>]

> Namely, is it possible to have too much iron in the water for plants?  I ask
> because our raw well water has 18ppm (yes, 18, not .18).  After it has been
> let to stand for a while, it turns a real nice caramel color, heh.  I am
> trying to stay away from having to use R/O water and I have proven to myself
> I can't reliably use the water from our filtration system (softened big
> time).  By default our water is soft, acidic, with a very high iron content
> with some tannins.  The soft/acidic part I can take care of easily as long
> as the iron isn't going to be a killer for me.

Not sure if there can be too much for the plants, but I know it will be 
toxic to the fish at some point, which I am sure will vary with the 
species. I have a well here too that we use for outdoor watering, and your 
water sounds similar (orange :-). I found that a lot of the iron in the 
water was actually in the form of fine particulates and a lot of shale, and 
I now separate out a *lot* of it using a "spin-down" type of filter. The 
spin-down filter makes a vortex inside the pushes the particulates to the 
outer perimeter of the filter and the outlet is in the center of the unit. 
The result is that the particulates precipitate down to the sediment trap 
in the bottom of the unit and cleanER water (this is not an RO system) 
comes out. It has a screen inside but not really a conventional filter 
cartridge and it is simple to clean.  I got one for about $50-60 from a 
place in Florida that sells them for irrigation use. I installed it to keep 
little mister-type sprinklers from clogging but I've found it does clear 
the water somewhat although I haven't done any "real" testing on the water 
either coming in or going out of the unit.

You might want to try one of the spin-down filters and see if it helps 
clear your water a bit. Even if it doesn't make a difference, it will 
separate out a lot of the particulates that would cause an RO system to 
clog more quickly.

> Also, if the plants (hopefully fish too) are ok with that much iron, will
> they suck it out of the water in time and get rid of the coloration?

I don't think the plants will take enough iron out of the water. My 
understanding is that the well water iron is not directly useable by the 
plants. You most like do not want to use softened water since the softener 
is just replacing Ca and Mg ions with Na ions which doesn't make it any 
better for a planted tank.

        -Bill

In Detroit, MI where everything is white with slick ice on top, and a lot 
of wind today too.

*****************************
Waveform Technology
UNIX Systems Administrator

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