# Crushed Limestone for substrates ??



## takechanmanus (Mar 19, 2006)

My friend gave me crushed limestone (a grain size 4-5 mm) for aquarium substrates. I believe this is a kind of gravel mixed in the concrete.

I see most of the plants are growing well with this substrate except Rotala Wallichii.  I wonder if limestone actually makes the water harder ?? I do 20-25% water change every 2 weeks, and I use RO water.

Does anyone have any thought ?

Tak


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## hoppycalif (Apr 7, 2005)

Limestone is calcium and magnesium for the water. Using it as a substrate means the GH would continually increase. I don't think this is usable for concrete either, because the cement reacts with it. Congrete is supposed to be made with inert sand/gravel.


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## takechanmanus (Mar 19, 2006)

Well, I mean people here use crushed limestone in the concrete as a gravel. I believe almost 80% of the time, they use this crushed limestone . . by the way, I am in Missouri . . i see limestones everywhere, and the water is TOO hard.

Tak


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