Looking for an opinion

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Global Moderator
Staff member
Jan 11, 2013
West Falls NY
Real Name
There’s a risk getting media or substrate from outside sources, but you can limit the risk by checking out where it’s coming from. If it’s from a healthy tank with healthy fish, it’s most likely ok, but there’s a risk. I have many tanks to pull from and I’ve given old media to people, a couple times people I met at petsmart getting bad info and I couldn’t help but step in.
In regards to the OP's situation, he's starting from brand new. You can bring anything in with new fish, or from established filtration / substrate. It's basically starting off as a quarantine tank.


Registered Member
Dec 10, 2020
I would recommend Dr.Tim's one and only for cycling freshwater fish tanks. I've been using this for 2years to cycle my 3 gallon Betta tank and it is good and really works well for me plus it doesn't cost that much.
Apr 2, 2002
New York
The there is this. Dr. Hovanec has a site where he sells his products and where he gives a ton of information. Here is what he has to say about using One and Only and fully stocking a tank, Oddly, it sounds very similar to what I laid out in my most recent post in this thread.

Using DrTim’s Aquatics One & Only Live Bacteria

The best and easiest way to fishless cycle is to combine adding the ammonium chloride with our Live Nitrifying bacteria. When used in combination, these will cycle the tank in less than one week. Again, do not add too much ammonia. We make it easy by providing a bottle of reagent grade ammonium chloride that is at a concentration such that adding 4 drops of solution to 1 gallon of aquarium water will result in an ammonia-nitrogen concentration of 2 mg/L (ppm)

The procedure is to add the ammonium chloride solution, shake the bottle of nitrifying bacteria well and add it to the aquarium. Measure ammonia and nitrite the next day and record. Add ½ dose and wait 24 hours and measure again. By day 5 to 7, you should be able to add 4 drops per gallon and the next day, ammonia and nitrite will be 0.

From https://www.drtimsaquatics.com/resources/fishless-cycling/
He also has a more detailed step-by-step page here https://www.drtimsaquatics.com/resources/library/quick-guide-to-fishless-cycling-with-one-and-only/

(Note: Dr. Tim uses the nitrogen scale when measuring ammonia, nitrite or nitrate. Our test kits mostly use the Total Ion Scale. So when he says to dose ammonia-n to 2 ppm, on an API kit this will read more like 2.5 ppm.

There is a reason for doing things this way. Because the nitrifying bacteria do not form spores, they eveolved a different strategy for surviving hard time, the go dormant. They do not feed etc. in this state. They can stay dormant for some time and as soon as what they need becomes available again, they wake up and go back to work. How long they survive as a viable group that is able to resume pretty much where it left off depends on what shape there were in when they went dormant. Also, after 5 months to a year, there will be individuals dying and there will be no reproduction. After a year they can take almost as much time to resume fully nitritfying capacity as if one were staring the cycle almost from scratch. But enough individuals can survive for many years that way. One viable bacterial cell can become two then four etc. This helps to insure survival of the species. But we need much more than that to help cycle a tank.

What this means for us using a product like Dr. Tim's is that how fast a bottle of his bacteria can result in a fully cycled tank will depend on how long the bacteria has been bottled. If kept at room temperature is should remain in pretty good shape for at least 6 months. Keep it in the fridge and this time can double. After that it becomes increasingly slower to resume full capacity relative to what it could do when it went into the bottle. This is why the bottle has a date stamp showing when the bacteria went into the bottle.
Apr 2, 2002
New York
Which of the two products, DrTim's or SafeStart, one might use is mostly based on where on lives. Tetra is headquartered in Germany and DrTim's in California. Therefore in the states we tend to use DrTim's and in Europe the use SafeStart.

The products were both developed by Dr. Hovanec when he was the Chief Scientist at Marineland. This company as well as Tetra are now owned by the same conglomerate. Both Dr. Hovananec and Tetra (by lineage) share the patent which protects their use of Nitrospira as the nitrite oxidizer in their respective products. Until the patents involved expire, these two products are the only ones which contain Nitrospira.

From a scientific point of view, there is no reason not to use either of these products. They both contain the strains of bacteria which have been shown, time and again, to be what are found in established (cycled) tanks. However, not everyone believes this.


AC Members
Mar 21, 2020
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why do you not recommend Tetra Safe Start?
Used FIVE bottles and did no cycle my tank at all whereas i did following there instructions.