

🚀 Kickstart your aquarium’s ecosystem with science-backed speed and power!
MicroBacter Start XLF is a 15x concentrated nitrifying bacteria solution designed to rapidly establish and maintain biological filtration in freshwater aquariums. It accelerates the nitrogen cycle within 5-7 days, safely reduces ammonia and nitrite levels, and supports high-density fish populations. Ideal for new setups, post-cleaning recovery, and ongoing tank health, this American-made formula ensures a stable, thriving aquatic environment.









| ASIN | B086Z6VTJW |
| ASIN | B086Z6VTJW |
| Age Range Description | All Life Stages |
| Best Sellers Rank | #10,077 in Pet Supplies ( See Top 100 in Pet Supplies ) #78 in Aquarium Water Treatments |
| Brand Name | Brightwell Aquatics |
| Customer Reviews | 4.6 4.6 out of 5 stars (1,302) |
| Date First Available | April 10, 2020 |
| Date First Available | April 10, 2020 |
| Directions | Important: Do not use this product with untreated tap water. First, use Brightwell Erase-Cl to completely remove chloramines and chlorine from tap water. Chloramine and chlorine are lethal to the bacteria in this product and if not removed will cause it to fail. Shake product vigorously immediately before using. Consult our website for the latest information and cycle schedule. Add the appropriate… |
| Included Components | MicroBacterStart XLF |
| Item Package Dimensions L x W x H | 4.8 x 1.54 x 1.46 inches |
| Item Weight | 4.97 Ounces |
| Item model number | BACSTARTXLF125 |
| Item model number | BACSTARTXLF125 |
| Manufacturer | Brightwell Aquatics |
| Manufacturer | Brightwell Aquatics |
| Model Name | MicroBacterStart XLF |
| Package Dimensions | 4.8 x 1.54 x 1.46 inches; 4.97 ounces |
| Size | 125-ml |
| Specific Uses for Product | Coat |
| Target Audience Keyword | Fish |
B**E
Great bacteria booster for starting and supporting a cycle
I’ve had very good results using Brightwell Aquatics MicroBacter alongside cycled or seeded bio media. Using both together really helps fast track the cycling process instead of starting from zero. It’s easy to dose and has been especially helpful when setting up new tanks or reinforcing an existing cycle after changes. Pairing it with established media has made cycling much quicker and less stressful. I like keeping it on hand for both new setups and ongoing tank maintenance.
G**️
100 % recommend!!
Amazing product!! My tank was cycling for over a month and no changes, my ammonia 0ppm, nitrite super high and barely any nitrate, and I was using brightwell florin bacter 7 which is great as well but for some reason wasn’t working for this bigger tank. So I did some research and it said I could just substitute the florin Bacter for the micro bacter start XLF since they’re the same brand and are compatible (do your research) so I did and after 4 days dosing it my tank was ready and no nitrites at all!! It was like magic. I recommend this to start cycling the tank since it’s so strong and then continue after water changes with the Florin Bacter7 which is what I’m doing and it’s going great so far. Also keep both in the fridge. One think I must add is that for some reason I thought the bottle was going to be bigger because of the picture they display but it’s still enough because it’s concentrated and it’s only to use once in a while. I also use it when I have ammonia in my nano tank I dose it for 2-3 days and it boosts the nitrifying bacteria 🙌🏻 love it and will buy again and again.
K**N
Good stuff worth the money
Absolute best way to start your tropical fish tank and have a perfect environment for fish survival. This stuff is a must and it works well.
C**L
Great stuff
This is the best quick start for bacteria that i have used. I’ve tried all the other brand names that everyone is aware of. My tank was cycled in a week. Will be my go to from now on.
E**L
errr probably worked?
So I moved from a 29 gallon to a 75 gallon and I only brought one decoration and a sponge filter from the 29 gallon. I noticed after 2 days my ammonia was converting but I honestly can't tell if its because my bacteria survived or because this is a great product. Nonetheless, I'm sure it aided in the process. I kind of bought this cause DrTim's was out but I'm sure it actually does work. Also the cap had a little hole so every time I shook a little would come out. Didn't affect my water clarity or anything. For the price I think it's alright.
C**S
This stuff works
I was having a bit of a problem 'cycling' the 125-gallon tank with Seachem Stability. Ordered the Brightwell Aquatics MicroBacterStart XLF and, combined with Fluval's Biological Enhancer added on top of the Seachem Stability, the tank was completely cycled within 48 hours. Granted, the Seachem had the ammonia taken care of, but the nitrites were just not budging and would escalate rapidly without major water changes and additions of Seachem Prime daily. I am SOOO glad to have found the Brightwell product.
D**M
Love it!!
This worked great! Wonderful purchase for cycling my axolotl tank, and worked like a charm. Would recommend 👌🏼
Z**Z
Multi-purpose
I got it to do two things: Keep the water clear in my pond, and help make liquid fertilizer. If you didn't know, you can put grass clippings and other organic stuff into water, and the water will leach out a lot of the good stuff. Eventually this progresses into a fermentation, and finally, nitrization. That's when bacteria start really turning the nitrogen in the liquid into something plants can use. Well, my liquid fertilizer mixture is still sitting, but not long after I added some of this, the water turned black. This is a good sign and shows that everything's working, and quickly! As for my pond, it looks great and has no problems. I recommend this item to people getting into homesteading, aquaculture, regenerative agriculture, making their own fertilizer, etc.
Trustpilot
2 months ago
2 days ago