It's not a bad idea at all.
The nutrient used by macro algae in your fuge is mainly ionic nitrate, not the raw dissolved organic matter removed by a skimmer. Using skimmer effluent won't "rob" your macro of nutrients. Feeding the fuge via the skimmer return may actually have the positive effect of cutting down on the detritus trapped in the macro algae. Regardless, a skimmer does not completely clean the water of organic matter as it's passing through it anyways - it is more of an accumulative effect over time.
When I saw someone running skimmer water through the fudge I was more than a little concerned for Marc
