As long as you're using water from the same water source for all of your water changes, there shouldn't be any pH stress. You should change water according to your fish- and therefore bio-load (wastes). The more the fish you have, the more water changes are usually needed. You can determine how many and how large water changes you need by measuring your water's nitrate concentration (through a nitrate test kit). Nitrate is safe up to 40 ppm, but above that it's considered too high. However, it's always best to keep your water as clean as possible, with 0 nitrate. Or at least always strive to keep the nitrate as low as possible, and certainly not exceeding 40 ppm.
Now, if you're using water from the same water source, regular weekly water changes, say at 10-30%, are safe. Of course the water needs to be dechlorinated if the water you use is chlorinated. Water changes are really healthy for fish. They remove toxins and nitrates from the water, which - if in large concentrations - can be dangerous to fish.
Which Cichlids? I have Angelfish that are Cichlids, and they live in neutral water (pH of 7.0 - sometimes slightly below or above that). They are doing really fine.
Now, how did you get your tank pH at 8? Did you use any chemical pH modifiers (i.e. commercial products to alter your pH). If your water source has a pH of 7.2 and the pH of your tank water is 8, I assume you must have altered the pH somehow.
It is not really safe to be adding any commercial pH adjusters to your water. That's because you'll have to use them on a regular basis to keep the pH at 8, including using the adjuster with every water change. This, in turn, may create unstable conditions - the pH will most likely fluctuate up and down. Remember that stable pH, even if a little lower or higher than you want it to be, is far safer that constantly fluctuating pH. The constantly fluctuating pH may make your fish very sick. pH scale is logarithmic, which means even one degree of change in pH can have serious consequences on the health of your fish. So, as I have said, it is always safer to keep a stable pH than to be adding commercial products to change your pH - this will cause dangerous fluctuations.
If you keep adding the water as it is, without altering your pH, your pH should stay more or less at 7.2 all the time. And that would be safe for fish. I don't know what kind of Cichlids you have, but if you have those that require hard alkaline water with very high pH, then perhaps someone else here will be able to help you with your problem. I personally wouldn't get fish that are not compatible with the pH of my water source. When you get fish that tolerate the pH that you have in your local water source, you avoid many problems this way. Besides, many tropical fish CAN get used to a pH quite different that the one they normally have in nature.
P.S. A more natural way in which you can alter your water's pH is filtering your water through peat - but that decreases the pH, and you'd like a higher pH. Also, adding properly prepared driftwood to your tank can help keep the pH lower. Live plants help keep the pH stable. However, when the plants are rotting instead of growing they release acids that also lower the pH. Excessive feeding that results in fish producing many wastes, and not enough water changes, may cause the wastes to acidify in water as well. Also, not enough water changes may cause the concentration of various elements such as calcium or various metals concentration, both of which cause the pH to go up.
They're african cichlids: kenyi, maingano, electric yellow lab, giraffe hap, orange blotch zebra, and a red finned hap. I've actually been thinking about slowly getting the water back down to it's regular ph, since it is, like you said, better to have a stable ph, and these fish can survive just well in my water's conditions (I see SEVERAL different ph conditions for all these fish, so it's hard to figure which to go by.)
You're welcome I don't really have any experience with the African Cichlids that you have, but perhaps someone will be able to help you (hopefully). Perhaps, if you just very slowly, little by little, decrease the pH to the one that your water source has, your fish may get used to it. You can achieve this by small water changes using water from your water source. HOWEVER, before you do anything, please wait for someone here to confirm whether African Cichlids will do well in a pH of 7.2.
African cichlids actually prefer the higher ph. I have multies and my ph is 7.6. They seem to be just fine with that, but a higher ph would be okay with them. I would not mess with the ph adjusters, and change the ph naturally. You can add crushed coral to your substrate or add a little of the coral placed in a bag or stocking, and put it in your filter if you have room. You can also try finding some Texas holey rock which is limestone, and it will naturally raise the ph in your tank. I think the ph adjusters are a bad idea. To wean off the adjusters and get your ph back to what comes out of the tank, try doing 10% daily water changes until it's back to normal. I don't think the 7.2 will affect your africans all that much, and you can slowly raise the ph back up naturally.