Lower pH

[Xscape]

Is there any way to lower my pH without using any chemical?
My pH is now 7.8-8 and i have arowana in the tank which i believe its too high for him.

 

[Gshock]

It's not too high as long as it is stable. You'll have more trouble if your pH starts to fluctuate.

 

[Calihawk]

Buy indian almond leaves, worked for me but I dont think I like it. Id rather keep things simple and not mess with pH anymore

 

[Chaitika]

I'd be more concerned with hardness. You can always use RO water or distilled, but like mentioned already, creating an unstable environment is worse than dealing with high ph or hardness.