What is this Black Substrate (quartz?)

[fishlove]

Hi, I was at Pasir Ris the other day and saw some black gravel around 2 to 3mm going for 2 bucks a kilo. They look real nice in water but some of it shapes exactly like a pinhead needle (looks like some dried up plastic prior to dripping) and it makes me wonder if this material is natural at all? Can they be used for low and high tech planting? I guess the important part is that base fertilizer right?

Thanks for your input.

FL

[|squee|]

Sure it can be used for planting, but whether or not the sand has too sharp points brings up lots of questions. Will it hurt fishes that roam along the sand surface? Will it damage plant roots?

[fishlove]

Haha, I threw that same question to the owner too and he lead me to few tanks loaded with corys. They look happy to me with no bruises on their underslung mouths. I suppose fish can take certain degree of punishement or else they would extinct eon ago, no?

Maybe I could use some seiner to filter out those 'needles'. BTW, Gex is going for $35 a pack of 9kg and then the black quartz will be $18. That's close to 50% saving! Wait a minute, you need to factor in fert. Well I suppose the saving is minimal in terms of 'lay chayness' and cost of time and effort.