The less you mess with your water the better things will be for you and your fish. A varying pH value will make for sick fish very quickly. Most reticulated (tap)water is OK for the vast majority of fish species. All you should need to do is make sure that when you first set up the aquarium and when you do large water changes, any Chlorine is either chemically neutralised by adding a "conditioner" or allowed to evaporate off. If you are having pH variations in an already established tank, you could use a pH stabiliser block/buffer. These are fairly cheap and should keep the water around pH7. I believe there are also various different blocks available that will actually adjust the water to suit both Alkaline and Acid loving fish too.
oak
Use the forearms
Use the forearms
Fake Coral
No. You should use aquarium salt, sold at pet stores.
Progress in the main storyline until you reach North Coast of Canada, after completing this part of the quest, the aquarium should be open for use.
I would use 4"x 3" timbers.
Anything labeled safe for aquarium use. Beyond that, it depends on what type of fish you are keeping, and whether or not you have plants, for which type of aquarium substrate (gravel or other lining for the bottom) should be used.
If they are in a pond, then having trees that are taller away from the pond should help. If they are in an aquarium, you should use a surge protector
basically you have to use an aquarium
A small pebble from inside the aquarium
In a marine REEF aquarium nitrates should be kept as close to 0 ppm as possible. In a fish only marine aquarium you should strive to keep your nitrates below 20 ppm.