hey buddy so you said its a seedling how high is your water in the bucket? if the roots haven't shown yet you may need to raise the water level higher so the roots can touch the water then as they grow out your net pot drop the water level down.
thanks for your reply mate its about 3 inches high I will try what you said and see if that works what about nutrients how much would you give it it is a 15 liters of water and thanks again for the advice