Peat hardening my water

[neon]

Hi all,

I am using an ion exchange resin to produce soft water from my tap water. The resultant water is:

0-1 DH General Hardness (GH)
6 DH Carbonate Hardness (KH)
7.5 pH

I then proceed to trickle this over peat in an attempt to produce soft, acid 'blackwater'. But for some reason the GH shoots up from 0DH to 6DH.

The resultant 'blackwater' composition is:

6 DH GH
0 DH KH
5 pH

I've used three different brands of Irish Moss Peat, which I've been assured is pure/untreated.

What is happening?

Any clues?

Thanks.

[SickLid]

From a chemical engineering point of view, what is the water parameters coming into the ion exchange column?

[neon]

The composition of the water going into the ion exchange column is:

20 °D GH
6 °D KH
pH 8.5

Thanks.

[SickLid]

I would try running it through the peat moss first and then run it through the ion exchange resins. Or run it through the ion exchange resins, then through the peat moss, and then through the ion exchange resins again.

The dKH of the inlet water to the ion exchange resin is the same as the outlet, so it shouldn't change your dKH significantly. When you run it the other way, 0 dGH through peat moss, the concentration gradient is so high that anything that can diffuse into your water will. I sometimes use RO Water to get rid of calcium deposits just because it is so good at dissolving stuff.

My knowledge of this is theoretical and not practical, so I am not sure if it makes sense or not. But based on the information you gave, it seems to me that this would work.

I would like to know either way.

M

[neon]

In fact, I did try what you suggested.

I'm first passing the water through the peat and then through the resin. The results are:

Original water: 20 dGH, 6 dKH, 8.5 ph
After Peat: 17 dGH, 0 dKH, 5 pH
After Resin: 0 dGH, 0 dKH, 5 pH

That works a treat - thanks a lot for your help.

Another question though...

Is there another way of decreasing KH besides using peat, say by using some chemicals that would be safe to use for aquarium water?

Thanks again.

[SickLid]

I use Kent's pH Control Minus to lower the dKH in my tank. Although at lower dKH's you would really have to watch how much you add. Kent has a lot written about it on there website:

<a href="http://www.kentmarine.com/phcm.html" target="_blank">Kent pH Control Minus</a>

They also provide pretty good technical support with their products. You can purchase it on AquariumPros at:

<a href="http://www.aquariumpros.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=APG&Product_Code=KEN03383&Category_Code=ADpf" target="_blank">AquariumPros sell Kent pH Control Minus</a>

And it shouldn't add un-needed phosphates to your aquarium.

Hope this helps,

M

[neon]

Hi Sicklid,

You mentioned phosphates. Is phospate harmful? I think Seachem's Discus buffer is phosphate based and I've used that in the past.

Should I use to a phosphate free product?

Thanks.

[SickLid]

From what I have read, algae loves phosphates, so a tank with high phosphates would have a greater chance of an algae bloom. But sometimes with the additives on the market, you can't get around putting them into your tank.

M