Cycled tank. 34 gallons. Today Tank: Ammonia =0.25, nitrates =20-40. I have been testing ammonia between 0 & 0.25 for over a month with no clear cause, so I have been ignoring it. So planning to water change (early for my weekly change, but I have time) but tested my source water & Tap: ammonia =1.0, nitrates = 10. (10-20?). In the past when my source water has had ammonia (0-4.0 at times over past 2+ years) my tank has been able to process it successfully in 24-48 hours. Just wondering if a water change is worth it. This is a higher nitrate reading in the source water than normal, it usually is like 5.