You can also use Cider Vinegar to lower ph, and baking soda to raise the ph.

But PH-Up and PH-Down are generally easier to use with better accuracy, and theyre not much more expensive really.
Considering that it doesn't take much of it, so 1 bottle of each will last quite a while.

You can get them at most pet stores for aquariums.
I think even some walmarts will carry it as well.