What kind of gravel is this?

[Gillian Burrus]

I am curious as to wether this will work in a drain and fill system. It passed the vinegar test, I have ordered a ph testing kit to see if it messes with levels. I have found this stuff for free, and it was put into a kiln, but i do not remember what the guy told me it was. And since it is free, I was wondering if i could get away with using it. Couldn't i just put smaller holes or add a screen to the bell syphon?

[George]

Looks like either slate or . . . . darned if I can remember the other but it looks like something commonly used in ap - should work very well.

[Gillian Burrus]

Not too small?  It is not 3/4" but it feels very light weight, and not harsh on the hands.  

[George]

either expanded slate or shale.  3/4 inch is recommended.  I'm using 1/2 with no problem.  Yours looks smaller.  Free - I would try it.  You need a gravel guard around your siphon, regardless of which media you use.  

[Gillian Burrus]

Alright, I am going to try it!

[Glenn]

Black cinder rock 1/4 -3/8 gravel, maybe? I  have used some from local landscape co. and all is not created equally and had different ph and tiny particle issues that needed a lot of washing/flushing.

[Gillian Burrus]

how long did it take for issues to show up?  I have tested it and it is sitting in water, i have ordered a ph kit to check that, but there were no bubbles when i poured vinegar on it.

[Glenn]

The dust that required rinsing more in the second batch showed up as soon as I began washing it. The first had not been so difficult. The pH issue did not present itself right away and was more than a week before it was realized that the pH through out the batch was different in three areas. So a more thorough wash and mix was required. So, I suggest doing your pH tests in three or more grab locations. And if they will, have your supplier mix any combined batches thoroughly.

 

 I would use Black Cinder Gravel again but I'd be on top of these two issues and watching for others.

 

Good luck.