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n00pster
01-05-2011, 01:19 PM
If anyone has had success growing plants on aragonite sand please reply.. thanks!

liz3
01-24-2011, 02:01 PM
since no one else has helped you so far, i'll share the experience i had. i have used aragonite/marine sand mixed before and found it difficult for the plants. i had a really fine aragonite sand grain mixed with very fine marine sand and i believe it was too fine for the plants...compacted around the roots a bit, IMO. however, pool filter sand has worked well for most plants. the aragonite and pH aspect of it also poses another issue. you would have to choose the plants wisely. anubias did manage to hang on in the aragonite / marine sand mix but not thrive.

HN1
01-24-2011, 02:24 PM
I could have sworn that I replied.... we use aragonite mixed with PFS in a few tanks to buffer the pH a bit. The club's Goodwill tank is setup with a mix and all is growing well.

n00pster
01-24-2011, 08:25 PM
Appreciate your replies. I am doing everything possible but not getting much response from the plants. I am dosing macro and micro ferts + CO2 + using 2WPG t5ho lights. And the only thing that is thriving is algae :)

I might try mixing some pool filter sand like you suggested as a final attempt at reviving the plants. I have anubias, java fern, amazon sword and vallisneria. Amazon sword and anubias atleast have some green leaves. vallisneria is dark brown and is kind of growing but at a really slow pace. Java fern acts like a plastic plant - neither dying nor growing with dull colored leaves.

gofish
01-24-2011, 10:29 PM
Besides driving your pH up and increasing the hardness of your water both of which can lock out your plants ability to absorb nutrients, aragonite sand has a low CEC (cation exchange capacity). This means that it doesn't attract or exchange cationic nutrients very well. This is important because plants use enzymes at their root hairs to exchange hydrogen ions for cationic nutrients in the substrate. Clay and organic substrates, on the other hand, have higher CEC values because they have a high surface to volume ratios and negative charges on those surfaces. I suspect that you would start seeing nutrient deficiencies in your plants with an aragonite sand substrate.

n00pster
01-25-2011, 08:13 PM
Besides driving your pH up and increasing the hardness of your water both of which can lock out your plants ability to absorb nutrients, aragonite sand has a low CEC (cation exchange capacity). This means that it doesn't attract or exchange cationic nutrients very well. This is important because plants use enzymes at their root hairs to exchange hydrogen ions for cationic nutrients in the substrate. Clay and organic substrates, on the other hand, have higher CEC values because they have a high surface to volume ratios and negative charges on those surfaces. I suspect that you would start seeing nutrient deficiencies in your plants with an aragonite sand substrate.

Thanks for the nice detailed explanation.

On a different note, have you see this relation between ph kh and co2? http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html
I assume that I need to increase my Kh and somehow keep ph low for higher concentration of CO2?

gofish
01-26-2011, 10:55 PM
I know type of chart very well. It is derived from the following equation:

ppm CO2 = 3 * KH in degrees * 10^(7-pH)

It refers to the following bicarbonate buffering system:

H2O + CO2<=> H2CO3 <=> H + HCO3- <=> 2H + CO3--

As far as the planted aquarium is concerned:



Injecting CO2 drives reaction to Carbonic Acid to Bicarbonate Ion plus Hydrogen (H+) resulting in a decreased pH. To avoid a pH crash, you need to add a buffer. I buffer with NaHCO3 (Baking Soda) to drive the reaction back, raising my KH (CO3--), pH (-log[H]), and CO2 levels. I typically try to maintain a KH of 4 degrees, a pH of ~6.8 which gives me a CO2 concentration of ~20 ppm as indicated on the chart you mentioned.

FYI: degrees KH = ppm KH / 17.8575

n00pster
01-28-2011, 11:48 PM
thanks for the explanation