As someone who actively works to hold down the pH level in tanks, I can tell you using peat in the filter, almond leaves, alder cones and bogwood is a far from ideal control method. You will have regular pH swings with every water change.
Changing pH is not the problem, controlling it so it stays within the range you want it to be is. I use a mix of ro/di water, muriatic acid, a mix of things used to stain the water and act to reinforce what else I am doing (almond leaves, alder cones and rooibos tea). I also use both a TDS meter and a pH meter to control what I am doing.
The reason for the RO/DI water is more than helping to soften it by lowering TDS. pH and KH are closely intertwined. You can not effectively manage the first without managing the second. Adding acid to water may drop the pH, but it also raises the TDS. RO/DI water has 0 KH and 0 GH. The 0 KH is essential to being able to lower pH effectively. Spring water, imo, is not what should be put into a tank.
As MBOU asked, we need to know what substrate and rocks you have in the tank as these are the most likely culprits in raising your pH. The amount- either too much or too little- of dissolved co2 in one's tap is also often the culprit. To much and the water comes out at a lower pH and as the excess co2 out gasses, the pH it rises. Too little co2 and it comes out at a higher pH and then drops as co2 in gasses. You can check for such a discrepancy by placing some tap water in a clean contained and then adding an air stone and letting it bubble for an hour or two and then test.
Before adding "spring" water to your tank, you might want to read this
http
/www.mnn.com/your-home/at-home/questions/whats-the-difference-between-distilled-water-spring-water-and-purified
You can also read here which has the following info:
5)Whenever possible, buy refrigerated bottled water and keep it refrigerated. Storage at or above room temperature promotes bacterial growth and increases leaching of plastic contaminants from the container into the water.
from
http
/www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&ved=0CFMQFjACOAo&url=http%3A%2F%2Fwww.extension.iastate.edu%2Fpublications%2Fpm1813.pdf&ei=cxKRUc-dCeLD0gH-74GgAQ&usg=AFQjCNGXBQEPZYPXQWAs-TCxB_1nvXsg8Q&bvm=bv.46340616,d.dmQ&cad=rja