Getting Ph Down

[foxycatfish]

Hi all,
Just after some tips on how i can lower my ph of my tanks.
Have seen in my lfs API ph down but does that work?
Thanks

 

[mark.w.jones]

Why are you looking to lower your pH?

What's it at now?
What size is your tank?
What's your current stock.

 

[foxycatfish]

the tank is 2.5ft
ph is 7.3
looking to put killifish in this tank now.
Tank has been set up for over a year with other fish but now would like to try killifish.