pH levels are at 6.0 - should it be higher

Question
I have a 65 gallon fish tank and recently lost three fish.  I had to do a water change and am working to get the correct levels in the tank.  I was informed by the pet store that my pH level needs to be around 7.6.  My tanks right now is around 6.0 to 6.2.  I was told to add baking soda to the tank.  How much should I add in order to achieve the levels that the pet store informed me?

Answer
Hello Clarence,
I'm sorry to hear about your poor fish...
I wish I knew what species you are keeping that would require such a high pH level from what yours is. Remember that most of the commonly available fish species can adapt and thrive in less-than-ideal water chemistry. These fish may not Spawn in this unpreffered chemistry, but as long as the water is kept clean and warm, most tropical fish have no problem with a less than ideal pH level. But then there are some fish who prefer and may not do as well in such a drastic differance than what they need to thrive. Mollies, platies, guppies, and the like are some of these fish who thrive much better in hard higher pH water. If it is your too-low pH level that caused your fishes s than you should certainly do something to raise the level.
First of all, I don't recommend using any chemicals to raise or adjust your pH level any way at all. For one simple reason, it is just temporary. And when these compounds are added, the pH will rise, but in the absence of akalinity (the buffering level which keeps your pH stable), the pH will drop and rise causing more harm than good. It is important to understand, quite simply, that fish will be healthier in a stable water chemistry with lots of water changes, rather than a specific one you try to maintain all the time. So basically what I am trying to say is; please don't use the chemicals. If you must raise your pH level or else, by far the best method is by adding African cichlid salts--when used as directed, will produce a stable (buffered) pH level of the desired value. Now another solution you can try is certain rocks which will raise Alkalinity and the pH level such as; crushed coral gravel, dolomite gravel, and limestone rocks. This method also provides the much needed and essential buffering compound. Keep in mind using rocks is a less than percise method than the cichlid salt and you may even end up with a very high pH of 8.2 in some cases. But still your best method is to not mess with your pH at all. If your local fish shop resides very close to your area--it is quite certain that the fish they keep are in the same tap water and chemistry that is at your place AND are adapted to that specific level and adjusting it may not be necessary. But of course I am only guessing at this. If your pH is not what is used to be weeks and weeks ago than it may be organic buildup in your aquarium causing the low pH the easy solution to this is more frequent water changes.
Unfortunately I have no experience in using baking soda to raise pH levels. So to be honest, I can't say for sure how much to use. I think in the long run using cichlid salts or using the rocks I mentioned would be a much better option. Always keep in mind unless you are keeping very difficult species, just about all of the commonly available fish species can adapt (and may have already) to your chemistry and as long as things are kept stable and water changes done frequently, they should in fact thrive.

I never mess with my pH. And I keep livebearers, tetras, barbs, cichlids, catfish, danios, rainbowfish, paradise fish, gouramis, bettas, angelfish, goldfish and more without ever adjusting my chemistry. And my angelfish pair spawn about every two weeks. I don't have the most perfect pH level either! But it does remain stable and I do very frequent signifigant water changes.

I really hope this helps, I am sorry I couldn't tell you what measurment to use for baking soda as I have never used it myself. And have never came across an aquarist who did use it.

If you have anymore questions, feel free to email me...
I do wish you the very best with your aquarium!

Happy holidays and Happy fishkeeping!
Karen~