Solved set potions with specific colors with own effects

Hi, I've made a plugin who give's players custom potions. I got serveral effects at one potion and so on but theres a problem. How I can chose the color of a potion?
I tried several things. Its possible to use

Potion potion = new Potion(PotionType.POISON);

to get a green potion, but if I do that, my potion will have a normal POISON-Effect, but I want only my own effects on this potion. I tried the following one

PotionMeta meta = (PotionMeta) i.getItemMeta();
meta.removeCustomEffect(PotionType.POISON.getEffectType());

but nothing changes.
I tried to write it with a demage value, Im not sure if this could help but I failed to try it.

Please help me, its possible to change the color but I want only my own effects!

 

ItemStack i = pot.toItemStack(5);
PotionMeta meta = (PotionMeta) i.getItemMeta();
meta.setColor(Color.FUCHSIA);
i.setItemMeta(meta);
p.getInventory().addItem(i);