I just tested my water for the first time in 5 days. Ammonia 0, nitrite 0, nitrate 10. However, my high range pH test was unbelievably purple. It was so purple, it looked like it was above 8.8. It's usually around 8.2. It has never been this high and I haven't done anything to the tank since Sunday when I did about a 20% water change. I've posted a picture of my tank; could the decorations because causing the spike? I haven't added anything new lately, though. The lot number of the pH bottle ends in 0409. Is it old? Should I even be worried about this?