Clownfish larvae collection from sump

Does anyone routinely collect their clown larvae from a sump? My breeding pair is in my reef tank, and I can't seem to get my snagger to catch more than 5-6 larvae. I know it's a flow issue in the tank, as it is an established mixed reef with lots of large acros, etc. I am hesitant to completely shut off the return pump and the powerheads and only have the snagged running, even for just a few hours. Murphy's law may prevail and I would fall asleep, forget it altogether, or something else, and kill my tank. I haven't been very successful at trying to collect the eggs for outside hatching in a tumbler because they will only make their nest on a nearly inaccessible piece of rock under their anemone. They absolutely refuse to lay on tile, pots, and the like. It is really amazing how they can move something that I think I have wedged into their area! Does anyone use some type of modification to their overflow to reduce the beating the newly hatched larvae would sustain in the ride down to the sump? Any suggestions or hints would be welcome.

 The eggs hatch within an hour or two of lights out, so you could turn the pumps off to collect the larvae and turn the pumps back on after they are collected.  The pumps being off for a couple hours won't hurt the reef.  Keep your biopellets churning if you have them though. 
 
Or you could try leaving just a small powerhead running in the tank overnight during collection.

Don't let fear and common sense stop you! =]

I set timers so that the pumps turn off just after dark and when I collect the babies I turn them back on. I have done this in a couple different tanks that have corals in them and have not noticed any harm to the corals. If your worried you will forget to turn the pumps back on you could just set the timers so they turn the pumps back on a couple hours later. Not sure how your sump is set up but it sounds to me that the babies would go through a lot of stress being pulled through an overflow then down into a sump. 

I like the idea of a timer on the return pump. Never thought of that, but that's why forums exist! Thanks for the suggestions. My sump is below the tank, and houses all the filtration, heaters, etc, and it is a rough ride down (I would imagine those larvae would feel like me going over Niagara Falls). I'll see about tracking down a good timer to hook my return pump into.