It's much more important to have a stable pH than to have a perfect 7 for the most part. Some fish demand a specific pH (below or above 7 depending on the fish) but unless you plan on keeping those fish, don't be too concerned unless your pH is fluctuating. Do you have hard water in your area? If you have water like mine, it has a high pH from the tap and buffers galore; your pH won't be going anywhere with additives. If you have very soft water with very little buffering capacity, you'll see your pH change a lot and will want to add a buffer like bicarbonate of soda for stability.
If your tap water is soft but you're still getting a high reading from your tank, it may be some of your decoration. If you have gravel, test a bit with vinegar to see if it fizzes. Anything made of shell in your tank will also bring your pH up.
Assuming it is your tap water and you still want to bring the pH down, you could try a few things. Bogwood in the tank or peat in the filter will help to soften your water a bit. You could also try using rain water instead of tap water, or invest in an RO unit (I wouldn't bother with that last one unless you've got your heart set on finicky fish like discus.) I've got a pH of 8 from the tap and no fish troubles though I wouldn't dream of trying any fish that require soft water without an RO unit.
Hope that helps a bit.
since putting some plants in there it has come down a bit! so i'll see how it goes over the next few days and maybe put some bog wood in there! cheers 
