It's way easier to gravel vac in a tank that has no fry.

Tank 3 now has 13 young males and they are looking great - I add 2 every second day. Tank 2 has 22 young males, the smallest is a bit quiet but I'm figuring he'd rather be back with his sisters of the same size (hoping that's all it is). These 22 will have to move into tank 3 (100litres) over the next 3 weeks which will make tank 3 a bit crowded with 35. Would 20% water changes twice a week be enough do you think? The plants are growing really well with lots of new shoots.

Tank 2 which is only 50 litres will then become the fry tank and I'll remove females from it back to tank 1. I'm going to have to approach some pet shops I think as there are fry everywhere in tank 1 and there is no way I can afford to set up another tank.

Remember my concerns about the flow with the canister filter in the new tank? Well the males in there just love it and spend much of their time swimming in the strongest part right in front of the outlet so I guess it's not a problem to them :)