Using Chipped Concrete Rocks As HardScape

**kingkew** · 25th Apr 2015, 23:46

Hi all,

I have recently picked up some chipped off concrete chunks from my neighbourhood and am wondering if they are safe for aquascaping.

They are submerged in tap water currently to be cleaned. Can anyone tell me if they will be safe for shrimps (CRS), plants (carpet) and fish?

**Urban Aquaria** · 26th Apr 2015, 00:15

If it's concrete, high chance they will leach and dissolve a lot of minerals into the water which raises general hardness (GH) and pH... it may be a problem if you are keeping livestock and plants that prefer lower pH soft water conditions.

This is especially so for shrimps, as GH levels that are too high will usually cause molting issues.

**kingkew** · 26th Apr 2015, 07:52

Originally Posted by Urban Aquaria

If it's concrete, high chance they will leach and dissolve a lot of minerals into the water which raises general hardness (GH) and pH... it may be a problem if you are keeping livestock and plants that prefer lower pH soft water conditions.

This is especially so for shrimps, as GH levels that are too high will usually cause molting issues.

Would it still be an issue if the concrete is soaked in tap water for a few days?

**Urban Aquaria** · 26th Apr 2015, 11:03

Originally Posted by kingkew

Would it still be an issue if the concrete is soaked in tap water for a few days?

For most rock materials, they will usually keep releasing minerals continuously over a very long period of time... so just soaking them for a few days doesn't make much of a difference (though you could use the soaking method to measure the amount of minerals being released using GH, calcium and magnesium test kits).

Some rocks release more minerals, some rocks release less, so for those using rocks in their tanks, its mainly a matter of choosing the right type and amount of rocks to balance their rate of mineral release versus livestock requirements (certain fauna like shrimps are more sensitive to mineral levels so more care has to be taken when adding rocks to their tanks).

There are 2 options if you are not sure of the rock characteristics and have no kits to test them with... either take the risk and just them add to the tank (have to monitor the livestock over time) or simply don't use the unknown rocks at all to avoid the risk.

**BFG** · 5th May 2015, 14:43

If the amount of concrete is small, hanging it in your toilet bowl water tank should help to assist in removing whatever it is you want removed. The constant flushing and filling up back of the water tank is better than having to manually soak it in a pail of water. Marine tank owner who diy concrete plug for their coral frag did it the same way.