Crushed up oyster shells for substrate

[LankyDutch]

Hi, I have been thinking about using a pile of eaten oysters for extra substrate in my tank. I have the flow of my wave maker set in such a way that it blows the fine sand away from the front part of the tank. I want to experiment using crushed oyster shell. Surely after boiling, drying and grinding they can't do much harm. I want to find out if this material has the right weight in order to stay put and will not be blown around. Does anyone have any experience with this?
Kind regards,
Hugo in The Netherlands

 

[BloopFish]

I would cure it for a while, or at least let the tank that has it cycle for a bit before putting in any valuable specimens in the tank. It should be OK. Oyster shells are mostly Calcium carbonate, with trace amounts of other compounds, some containing phosphorous, sulfur, silica, etc. Thus, you might experience a small algae bloom. Due to the impurities, I personally would not trust it with an established tank - at least not in large quantities. Corals can be very sensitive to even trace amounts of anything that they do not like, so I wouldn't add it to an established tank from the get go because it might mess with the equilibrium of your tank. It would be cool to set up another tank with the crushed oyster shells though.

Table 2 of page 2 of this paper has the chemical composition of a sample of oyster shell, it should be an interesting read. https://www.researchgate.net/public...nical_characteristics_of_crushed_oyster-shell

 

[LankyDutch]

I would cure it for a while, or at least let the tank that has it cycle for a bit before putting in any valuable specimens in the tank. It should be OK. Oyster shells are mostly Calcium carbonate, with trace amounts of other compounds, some containing phosphorous, sulfur, silica, etc. Thus, you might experience a small algae bloom. Due to the impurities, I personally would not trust it with an established tank - at least not in large quantities. Corals can be very sensitive to even trace amounts of anything that they do not like, so I wouldn't add it to an established tank from the get go because it might mess with the equilibrium of your tank. It would be cool to set up another tank with the crushed oyster shells though.

Table 2 of page 2 of this paper has the chemical composition of a sample of oyster shell, it should be an interesting read. https://www.researchgate.net/public...nical_characteristics_of_crushed_oyster-shell

Thx Bloopfish, you make some good points. I am gonna try curing the crushed shells first. I will use old tank water after a water change and gradually add the amount of rubble I need I think.