I'd rinse them off first before putting in the tank.
Leggy seedlings are a sign of not enough light or the light is too far away from them.
Ya know aphids can simply be sprayed off the plants with water if pulling the plants out seems like it will be too hard on them. If you have ants farming them, then the ants would just bring them back but otherwise just spraying the plants regularly can sometimes take care of it.
Granted, indoor growing can have more issues with aphids, whiteflys, spider mites and some others getting out of hand because you don't have the natural controls of them like outdoors so you might have to be more proactive at controlling those things than I have to.
We were just introduced to a new natural bug repellent yesterday that we are going to try out. It is called Soap Nuts and it is a fruit that grows in Taiwan and is farmed and shipped here. Apparently it is useful as a laundry detergent, a hand soap, an insect repellent and treats aphids and whiteflys. It suds very little, so may be a great natural alternative for pest control. We will try it out and let you know! They say they even use it as a wash for their dogs and it is a flea repellent too.