# AquaSoil + Powersand in Hard Water



## Rolo (May 12, 2004)

I'm hoping to get some foresight on how Aquasoil would work out with very hard water.

My KH is 21°, the GH is 25°, and the pH stabilizes at 8.4. With these extreme parameters will Aqua Soil be able to lower hardness and pH as designed _longterm_?

And how exactly does it do it...

I assume GH is lowered by absorbing Ca and Mg ions due to high CEC. Eventually wouldn't the substrate "fill-up" with repeated exposure to hard water after many water changes, and stop lowering the GH?

What happens to the KH - Does Aqua Soil lower this too or does it release other non-carbonate buffers? Acids?

Chris


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## plantbrain (Jan 23, 2004)

It will not do much to your GH/KH over the long term, that's impossible for the reason's you stated. It will(any substrate pretty much) have a lower pH than the water column, most all substrates tend towards neutral due to bacterial cycling. 

As far as the how on GH/KH, you are on the right track.

If you want to lower the GH/KH, use RO.
That will help more than any substrate will.

Regards, 
Tom Barr


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## Rolo (May 12, 2004)

Thanks for the confirmations. I wasn't considering Aquasoil + Powersand for the sole benefit of lowering water hardness. Just trying to get an idea of what to expect.

I will to end up investing in an RO unit now too. I've grown plants in hard water in the range of 17-20 for GH and KH. But now I just moved locally and the tap fluctuates too much. Today readings were over 30°!

So I will soon be able to obtain virtually any water hardness. 

Anyone know Amano's or what the usual Japanese tap hardness is?
With Aquasoil + Powersand what hardness would be best to use?


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## plantbrain (Jan 23, 2004)

His tap is rather soft from what I heard.
KH about 3-4
GH about the same.

I'll trust it when I test it myself.

One thing about variations in the tap's KH.

Your rate of CO2 dosing, unless you use a pH controller will be stable.
Therefore the CO2 ppm will also be stable pretty much as well. Plant uptake of CO2 will also be stable.

When doing the CO2 adjustment check etc, you should always double check the KH...just in case.

I have not found any issues doing this over the years. Oncve the CO2 dosing is stable, the water changes seldom effect the CO2 levels even if the KH changes.

Still, the KH of 30 seems extreme.
GH might be fine.

I really do not know what an ideal KH or GH would be. 1 to 25 seems fine to me, a few species, perhaps 2-3 do better are lower KH's.
Out of 300 species, that's hardly a trend.

Regards, 
Tom Barr


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