Just ran it under some water and rung it out until water was able to flow through it.
Is the light part of the problem? This reptile light is pretty much artificial sunlight. I think I'll turn it off for a couple of days like Plague recommended. These fish are all nocturnal bottom dwellers, so I don't think it will affect them much.
Any chlorine/chloramine in the water possibly killed any bacteria left in the media.
The only way to know would be to test for ammonia, nitrite and nitrate.