Got it, thanks. Would being more aggressive with the bleach be a strategy, e.g. if 2gals is to get me to 10 FC, would putting 3 or 4 gals at a time give me a better chance of breaking the ammonia?No need for a new test kit. We know what it is. As for the water exchange, it's really your call based on water cost in your area and what you've done so far. Lots of folks get ammonia each year and make it through, but early intervention and 10-min testing is critical. Yes, you'll use some bleach, but once you break through you'll know it because the FC will hold.