Moving Fish Between Tanks

Yesterday I moved my male v. platy and 5 peppered cory out of the 50L tank and into a 70L tank, and moved the glass bloodfins from the 50L tank into the newly planted 125L tank. I emptied the 50L, planted it, put some of the wood and other décor back in, and have been running it with the filter overnight, along with some prawns and chopped mussels in a mesh bag, to feed the bacteria.
My question now is when can I move the platy and cory back into the 50L? I'm going to test the water later today, after I have cleaned some of the other tanks, but I'm just a bit concerned that if the fish are moved again too soon after the first move, will it stress them out? And how soon is too soon to move the fish again?
Any advice appreciated.
Thanks.

Thanks Colin, that's good to know. 

I moved them yesterday and they settled into the 70L tank almost immediately. Today they are pottering around as if they have always been there.
Now that I've planted the 50L tank there are a lot more places to hide and explore, so I hope they like it, whenever they move back.

Moving the fish back to the 50L tank went well.
I have now moved the fish from the 70L temperate tank into the 70L quarantine tank so I can do some more planting. That move did not go quite so smoothly, as the female platy have always been a bit wary of the net. I can see them having to stay in the quarantine tank a lot longer before moving them back, to avoid too much stress.

The peppered cory, zebra danio and leopard danio seem ok. The female platy are none too impressed.
Actually I can see Booboo (the one that didn't get pregnant) at the front of the tank now, probably wondering where the food is. She is quite big and a bit of time without food will probably do her the world of good.

Me too! 

After a quick Google it seems it is just a red net made by Penn Plax which means "Some fish like catfish have a hard time seeing this net and become easier to catch. Other fish like swordtails can see it just like any other net"

See http://www.advancedaquarist.com/blog/red-fishnets for more detail

Infra red net?? Is this some sort of Star Trek tractor beam thingy??? The physicist in me is curious to the point of dubiosity!

IKR! I had a quiet internal snigger when I spotted it.

BTW Donna catching fish in a planted tank is a nightmare. Luckily my sparklers were relatively easy to catch after I moved out the heater, the filter and the bogwood. We managed to nudge them in the net with a bamboo skewer.

I feel like a bit of a prune for not thinking of that idea for myself. 
Two nets would make things a bit easier, so I will get a green net this week, before trying to move my fish back into the planted 70L tank. 

You really need two nets to catch fish. I find that using a  small white net to chase fish into a larger green one held still is best, the green one perhaps looks like plants to fish and so they are more likely to swim into it.

My catch net is a big brown one which was perfect in the shrimpery as it has a black background. Methinks I'll be buying a green net. Great tip Richard.

Good lord, catching fish with 2 nets makes life so much easier. Thanks Richard.
It took me a fraction of the time to return all fish to the planted 70L temperate tank, and the fish seem less stressed about the whole thing as well.
Hooray!
 
Just a few more bits to pick up on Friday and hopefully I can spend the rest of the day moving tanks around.