The substrate that makes acidic water?

[shaman]

I have been using some pebbles that has very rough surface and its brownish red in colour. I suspect it is able to turn the water acidic.
Please help to ID the pebble. Can it really make water acidic?

[michael lai]

Hi shaman,
Even with this picture, a 'SHAMAN' will not be able to help you. If you are able to provide the name of the package( bag ) I think it will shed some light to your query ( forgive my pun )

[zeotz]

how big are these pebbles u refer to? cant tell the size from the pic.

I had some volcanic rocks with same texture and color as big as 5" diameter and i suspected they were contributing to algae so i took them out. so far algea is in check. but not sure about acidity.

[zeotz]

o.. forgot to mention, mine is a marine tank.

[shaman]

Oh~ sorry for the lack of info. Ths size of the pebbles is about 2 to 3 cm. I buy them in 1 bag without name from the lfs. Its brown and reddish.

[|squee|]

Might be crumbled lava rocks?

Do the vinegar test, if it bubbles don't use it anyway, since it affects something in your water.

[bclee]

Why do you suspect that it turns your water acidic?

What is the pH and KH of the water? Do you inject CO2?

BC

[shaman]

The water has nothing but pebbles, 1 driftwood, 1 clay container (used for aroma therapy). The tank is full of green beard algae. I didnt care much about the tank. I keep tiger barbs inside.
The water is quite acidic. About pH 6. So I wonder what caused it to go acidic as tap water is about pH 7.5
Anyway I can find out why? Thanks

[|squee|]

The driftwood will definately turn your water acidic to a variable extent.