expanded clay for ebb and flood system?

[skaldyr]

Im gathering things to start a ebb and flood system.

Does it matter what expanded clay i get?

Can the type of expanded clay you find in the supermarket be used. or does it have to be specifically for hydroponics? the supermarket stuff is cheaper.

[denSiS]

Yeah you can use the supermarket stuff but make sure you wash it really good. One thing that can create a problem is that they might contain alot of limestone and that will rise the ph. The special hydroponic clay are ph stabilised to ph 7.

[skaldyr]

Thanks
I will try to find the hydroponics clay then. sounds like its easier to work with.