Depends on the rubber compound.
For the two alcohols listed above:
SBR is the most common synthetic rubber made, it is compatible.
Nitrile is the most common rubber used in air hoses. It is not compatible with EA, and cautionary with IA.
EPDM is compatible with both.
PVC, use caution. It can swell then crack.
Buna-N, the most common O-Ring material, no problem. Viton and Urethane O-Rings are unacceptable.
Neoprene is good to fair.
PP (polypropylene) Is the best choice for air lines. HDPE and LDPE (high and low density polyethylene) are also good choices. Either one of these 3 would be a good choice for air lines and fittings.
Nylon for air lines is also a good choice, but may be more expensive. Very strong, but need to keep it out of the sun.
I can't see any material markings on the Vertex diffuser I have in my hand. I am not sure, but I thought the membrane was EPDM??? Not sure as to what the housing is made of. No markings!!!
If you see this symbol with anything dealing with your fish or chemical compatibility with things that won't kill your fish, you're good to go.
Scott, take some of that Everclear you PM'd the apple pie recipe for and dump it on the back side of a diffuser. We can't get the good stuff in MI
