How do I cycle my tank fast with bottled bacteria?

Short answer: Add a bottle of live nitrifying bacteria (Dr. Tim's One & Only or Fritz TurboStart 900) and an ammonia source at the same time, turn off your skimmer and UV, and test daily. This seeds the colony instead of waiting weeks for it to appear — most tanks finish in about 5–14 days. Product freshness is the make-or-break factor.

The details — the steps (Dr. Tim's style)

1. Prep the tank. Salt water at ~1.025 sg, heater at 75–78°F, flow running. If your source water is chlorinated, dechlorinate first and wait ~30 minutes before adding bacteria.
2. Turn OFF the protein skimmer, UV sterilizer, and ozone. They strip out the bacteria before it can colonize. Keep them off 48 hours for Dr. Tim's, up to 5 days for Fritz. Remove filter socks for ~48 hours too.
3. Add the entire bottle of bacteria sized for your tank volume.
4. Add the ammonia source immediately — the bacteria need food or they die. Dose ammonium chloride to ~2 ppm (about 4 drops/gallon of Dr. Tim's). Never exceed 5 ppm.
5. Test daily. Both ammonia and nitrite should climb and then fall over the following days.
6. Redose ammonia to ~2 ppm only when both ammonia and nitrite drop below ~1 ppm. Don't chase the exact number.
7. Confirm with the 24-hour test in is-my-tank-done-cycling.

Fritz TurboStart note: standard dose is 1 oz per 25 gallons; you can safely use up to 5× to go faster. Manufacturer claims 5 days or less; real-world is typically 5–14 days, and some report 24–48 hours with heavy fresh dosing.

The numbers

Common mistakes

• Dead bacteria from bad handling. Live bacteria have a shelf life and hate heat. Buy fresh, prefer sellers who ship cold, check the expiration date, and refrigerate on arrival.
• Leaving the skimmer/UV running. They physically remove or kill the bacteria you just paid for.
• No ammonia source. Bacteria with no food starve within days. Bottle + ammonia together, always.
• Assuming "instant" means "skip testing." Even a fast cycle must be confirmed by test, not by the label's promise.

When to worry

• Normal: A small ammonia/nitrite bump in the first days even with bottled bacteria — the colony is still scaling up.
• Worry: Zero movement after a week with a bottle that arrived warm or expired — you likely got dead product. Re-dose with a fresh, cold-shipped bottle.

What's next

Watch the phases in cycling-water-parameters-by-phase and confirm the finish in is-my-tank-done-cycling.