Black lava rock?

[Jim Sinclair]

Is there any difference between red and black lava rock for biological filtration? All the videos I've seen recommending lava rock show red lava rock. At my local Lowe's a 6-pound bag of red lava rock costs $7.98, while a 16-pound bag of black lava rock costs $8.98--just one dollar more for 10 more pounds. What's the difference (other than color) between black and red lava rock?

 

[Slaphppy7]

I don't think the color difference matters at all for filtration

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