Tell you what:
Try filtration through peat. Fluval has concentrated peat pellets (I just bought two boxes).
Before you get there, and to do this safely, you will need
GH and KH liquid test. These test work by tritation method: you add one drop at a time, shake and keep adding and shaking until the color changes. If you measure with 10ml of water you can have reasonably accurate measurements of 0.5 degress of hardness.
Only if you have very hard water you won't be able to pull this off.
I've been tampering with pH, to bring it down for a few months already. I happen to have very cheap (5gal for USD1.25) R/O processed drinking water available locally (and the guys at the store deliver the 5gal bottles orders in five minutes).
This takes time and is not risk free but is doable if you have the love for this.
I recently ordered 20 Seachem's pH Alert -works great, real good simple technology behind this. These units don't replace pH readings but come handy if something goes wrong, they last for 6 months in freshwater and 3 in saltwater.
Another option, if your water is moderately high is to use Indian Almond Tree leaves. For pH down in a 145gal tank I use 18 mid-to-large sized leaves (for free in my street all year around), just replace it every two to three weeks.
Whether you go with peat or Indian Almond Tree Leaves, you can use activated charcoal if you don't want the tea-color water they will produce.
A third option, but that depends also of your tap water hardness level, is to use CO2 injection to drop pH. For this to happen you will need to be careful not to over-saturate the tank with CO2 but also to keep a relatively constant input of reasonable high levels of CO2. Going pressurized (a dream for me yet) is the safest and fastest way to go if you opt for fully automated systems (quite expensive); going the
DIY way could work (my method) if you are up to the task (requires maintenance).
At the end if your water is too hard, mixing with R/O might be the only effective choice.
Hope this info helps you.
Pepe
Santo Domingo