LED/LDR's got me confused

[Jason D]

How much voltage or current can the LED side of this things handle.
I just bought a VTL5C3/2 and a VTL5C3 to use in the LERA and Single Pot LFO Mod for my Neovibe. I am pretty sure I blew out the dual photocoupler . And I may have done the same for the VTL5C3.

I tested the VTL5C3 with the DMM and a I am getting 0.325 V foward biased and .305 V reversed biased.(using the diode test function)
And, around 450 ohms through it. So, is it still good?

[Tim Escobedo]

Probably a good idea to limit the current through any LED to under 20mA.

[smoguzbenjamin]

Running a LED at anything over 20mA will drain your battery faster than you'd want anyway