PH level

Question
Hi, Our 40 gal. aquarium has cycled and has maintained levels for about 9
weeks now. Our ammonia is at 0.0, our nitrite is at 0.00 and our nitrates are
at about 3.0. Temp. at a steady 77. The pH is a concern. Our water here in
San Diego is hard and the level keeps creeping back up to 7.8 or so. We have
used Proper pH 7.0 and a few other products. They bring it down for a while
but it always goes back up. We have 5 glass-cats, 3 bala sharks (my
favorites), 1 pleco, and 3 goldfish, yes goldfish. I used them to cycle and my
wife won't part with them. All fish act and look healthy. No problems at all.
The bala's and the goldfish swim together, sleep together, etc. I have been
told they (the goldfish) need to come out, why? We use a 305 fluval canister
filter along with an emporer 400 bio-wheel filter. I guess we are cycling about
700 gph. The water is crystal clear. I have been told to use driftwood to lower
the ph. I have researched it as well. My question(s), will the discoloration (if
any after I properly boil, and patiently soak etc. the pieces) eventually subside
and/or completely go away and will the driftwood really help with the ph
significantly enough to matter and if so for how long? I am also told that a
consistent ph is more important than a perfect ph so just leave it alone. What
are your thoughts and recommendations?

Answer
Hi Mike,
Usually the pH is not a concern.  It is very hard to alter the pH without changing the KH and GH.  Its like a triangle.  Products like pH UP and pH Down dont work because of buffers in the water.  Its easier to make the fish adapt to the water rather than the water adapt to the fish if you get what I mean.  7.8 pH is not in the extreme zones and the fish will be fine.  I would personally just leave it alone.  I know some aquarists that have 8.0-8.5 and the fish are perfectly fine.  

You have both tropical fish and cold-water fish (goldfish) and its better to keep one or the other.  Its a hassle to keep the water at a temperature perfect for both because both types will never be satisfied.  Unless you keep the temperature just right for the tropicals since these are your main fish and make the goldfish adapt to the warmer waters.  

Driftwood does lower pH.  However, you need a lot of driftwood.  Which will mean a lot of tannins.  I boiled mine and the it does not leech any more tannins in the water.  But if you are planning to use driftwood to lower the pH, you must get a lot.  

Some people keep a ton of live plants and want to inject CO2.  The pH lowers a significant amount.  For example mine lowers from 7.8 to 6.8.  You could try that route but it is costly.  A CO2 system will cost $300 brand new.   
-Matt-