# Limestone Gravel Substrate?



## jho1984 (Sep 12, 2012)

Hello I am in the process of setting up a new aquarium for Malawi Cichlids. I was able to swing a trade on Craigslist for a used Fluval Osaka 260. It is going to be a primarily rock cave tank and I am contemplating different substrates to use instead of Crushed Coral, or gravel. I have been to several local stone quarries and have found they have pre-washed Limestone Gravel less than 1/2" in size. I have always used Limestone Holey Rock as caves and a buffer for Cichlids. I am interested in using this as a substrate and being able to do away with Holey Rock as a buffer for my fish. Has anyone attempted this before? Or any advice would be greatly appreciated.

Thanks


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## DJRansome (Oct 29, 2005)

I have not found buffering substrate to make any difference one way or ther other in my tanks (7 years now). So I'd say just get what you like. For a natural sand I like pool filter sand.


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## GTZ (Apr 21, 2010)

Crushed coral is nearly useless as a buffer due to it's hardness. Aragonite is slightly better when used in a filter bag but maxes out around 7.5 pH. As a substrate there isn't enough current to break it down where it will make a difference. Coupled with that, weekly water changes that are recommended for Malawi tanks negate any benefits that it may provide. If you need to buffer, (check your tap KH and GH levels) you're better off using an epsom salt and/or baking soda formula during water changes.


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