Milk in a reef

[canadawest]

Considering milk is mostly water, I would suspect it would have little to no effect on the tank at all.

Not sure how big your tank is, but a quarter cup shouldn't hurt at all.

Your skimmer might be busy for the next few hours pulling out extra protiens from the milk, and who knows, maybe you will get a micro-calcium boost?

If you don't notice anything odd by tomorrow, I'd say everything is fine.