One And Only Saltwater Live Nitrifying Bacteria – Dr.Tims 500 ml

Dr. Tim’s One & Only instantly establishes a saltwater biofilter, eliminating new tank syndrome and removing toxic ammonia and nitrite without odor.

Size: 500 ml

Instantly create a bio filter in saltwater aquariums that can eliminate new tank syndrome and remove toxic ammonia and nitrite without any sulfurs or odors.

Perfect for fishless cycling new aquariums, especially if used with Dr.Tim's Ammonium Chloride.

Dr.Tim's One and Only Live Nitrifying Bacteria for saltwater tanks is widely used throughout the hobby and can be used to help prevent common issues with new tanks while helping stabilize existing tanks. Dr. Tim is considered to be one of the premier authorities on marine nitrifying bacteria in open and closed systems. One & Only contains millions of live nitrifying bacteria that will help quickly establish a biological filter in your aquarium allowing you to add fish almost immediately.

• New Tanks.
• After Water Changes.
• Adding New Fish.
• After Treatments.

Refrigeration not required - Never freeze or store in temperature over 95°F - Stable for up to 6 months at room temperatures and up to 1 year at temperatures ranging 40°F to 50°F.

The One And Only Saltwater Live Nitrifying Bacteria - Dr.Tims 500 ml introduces live nitrifying bacteria to jump-start biological filtration — see our guide to the Nitrogen Cycle for why this matters when setting up or restarting a tank.

Compatibility

This is the saltwater formula. DrTim's make One & Only in separate formulations for freshwater, saltwater, reef, nano and seahorse aquaria, and for koi ponds and water gardens. Ours is the saltwater one, part DT-20.

Brackish tanks — the rule is by salinity, not by intention. Below 10 ppt (specific gravity 1.007) DrTim's say use the freshwater formula. At or above 10 ppt, use this one.

What it will not do. DrTim's are unusually direct about this: One & Only is not a sludge buster and it will not remove nitrate. It does one job — establishing a working biological filter so ammonia and nitrite stay below toxic levels. For sludge, organics and nitrate their answer is Waste-Away, which we also stock.

Turn the UV and the skimmer off. Both should be off before dosing and stay off for 36 to 48 hours. This is the most commonly ignored instruction on the bottle and the most common reason people conclude the product did not work.

Dechlorinator compatibility, which is a real trap. The water must be dechlorinated before dosing — but DrTim's warn that some dechlorinators are actively harmful to the bacteria: do not use any product containing aldehydes. They confirm their own AquaCleanse is safe. If your conditioner's ingredients are not published, dose the conditioner, wait, and then add the bacteria rather than adding both together.

Uncured live rock will overwhelm it. DrTim's say plainly that on a new saltwater tank set up with uncured rock, One & Only may not be able to control the ammonia, because the decaying organic matter produces more than the starting bacterial population can process. Cure the rock first, or expect to dose again.

Sensitive species should wait. Some fish react to any measurable ammonia; DrTim's suggest keeping those out of the tank for the first twenty days or so after setting up, whatever your test kit says.

After medications. Antibiotics and many chemical treatments kill nitrifying bacteria. Re-dosing One & Only after a course of treatment, after a heavy gravel clean, or after a filter failure is exactly what it is for.

It needs somewhere to live. A bare-bottomed tank with no filter media gives the bacteria nothing to colonise — glass walls and a plastic filter grid are not enough surface area. If you are cycling a quarantine tank, put a sponge filter, some substrate or a filter cartridge in it first. This is DrTim's own answer to the most common complaint they get.

If the water goes cloudy the day after dosing, that is not this product. Nitrifiers cannot multiply fast enough to cloud water. Cloudiness is a heterotrophic bloom feeding on organics — do a partial water change, cut back feeding, and it clears in a day or two.

Dosage & Directions

Shake the bottle hard before you open it. DrTim's give a simple test: if what you pour is a clear liquid, you have not shaken it enough. The bacteria are grown on a solid microstructure rather than floating free, and that is what settles to the bottom.

The dose. DrTim's print a minimum of 10 mL per 10 US gallons (about 38 litres) on the label. Their bottle-size chart is more generous than that — it rates a 2 oz (59 mL) bottle for 30 gallons / 114 litres, which works out at roughly double the minimum — so treat 10 mL per 38 L as the floor and the chart rate as the figure to actually use.

On that basis this 500 mL bottle treats about 960 litres (250 US gallons) at the chart rate, or up to about 1,900 litres at the bare minimum dose.

DrTim's would rather you used the whole bottle at once. Their label says so in as many words: for best results, use the entire contents at one time. And cannot be overdosed — there is no penalty for putting in too much, only for putting in too little.

The order of operations, which matters more than the dose:

1. Set the tank up, bring it to temperature, and make sure the water is dechlorinated first.
2. Start the filter and check it is actually running.
3. Turn off your UV steriliser and your protein skimmer — and leave them off for 36 to 48 hours afterwards. A UV kills bacteria in the water column; a skimmer strips them out. Both will remove what you just paid for.
4. Shake, then pour the One & Only over the biological filter media. If you have no dedicated media, pouring it into the tank is fine.
5. Add fish within 24 hours, or add ammonia. The bacteria need a food source immediately or the population starts to fall away.

How many fish to start with. DrTim's rule of thumb is one giant-danio-sized fish per gallon at the initial dose. Feed normally, test ammonia and nitrite, expect perhaps a trace for a day or so, and add more once it clears.

For a fishless cycle: dose the One & Only, then bring ammonia to 2–4 ppm. It should fall away quickly. Dose ammonia once or twice more, and once your tests read zero ammonia and zero nitrite you can start stocking. DrTim's own view is that there is no particular reason to cycle fishless when using this product — but it works if you prefer to.

If your tank already has high ammonia or nitrite — above about 10 ppm — do a water change before dosing. Nitrifiers prefer low concentrations and are actually inhibited by high ones, so dosing into a crashed tank works more slowly, not faster.

Storage: never freeze it, and never let it sit above 95 °F (35 °C). DrTim's rate it for 6 months at normal room temperature and a year at around 50 °F (10 °C); refrigeration is not required but gives the longest life. Every bottle is stamped on the back with a ‘best used by’ month and year — past it the product is not dead, only weaker.

Backorder & Dispatch Timeline

This item is stocked to order. Back-orders are consolidated and placed with our overseas suppliers once a month, on the last day of the month, and all such orders are shipped before the 15th of the following month.

Back-orders cannot be cancelled once they have been placed with the supplier. If you cancel before that, payment-gateway charges of 2% plus GST are deducted and the balance refunded. In the rare case a supplier cannot fulfil the item, we will offer you an alternative first, and refund in full with no deduction if you would rather not take it.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number — or email us, if you would rather — and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months' remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.