FluvalCycle Biological Enhancer, Aquarium Water Treatment, 16.9 Oz., A8351

Great for water changes and weekly maintenance. Highly recommended

So I know this product is meant to kick start your aquarium until it stabilizes but as someone who travels and needs to rely on others to keep my fish alive, this product is literally a life saver.I have the person caring for my tank put a capful in every other day and it helps keep the tank stable. No more fish doing the back float due to spikes in nitrates or ammonia.

This stuff is a absolute necessity, If you're new to owning fish or If you just want to set up a brand new tank. You need this Beneficial Bacteria to start up the Nitrogen Cycle in your tank and this is the best way to get it. For those who's new to owning fish or who doesn't know what the nitrogen cycle is and why it is important to your fish to keep them healthy, Im going to explain the easy way. Basically What the Nitrogen Cycle is and why is it important to your fish is because the Nitrogen Cycle is the process of GOOD BACTERICA that is introduced into your tank to help lower the Ammonia, Phosphates, Nitrate Levels that builds naturally from your fish, Un eaten food, and its Poop. Ammonia is the LEADING CAUSE OF FISH Death is given out naturally through your fish's Gills or its POOP, or uneaten food. now back to the Nitrogen CYCLE, which is very easy to understand if explained easliy with out all its technical mumbo jumbo.its basically the introduction of the GOOD bacteria into your tank, now your Ammonia, Nitrate, and Phosphate levels will go up, but don't worry its Suppose to do that, so don't go crazy doing water changes or adding chemicals to lower these levels no. The Beneficial Bacteria will do that for you in that case will provide a healthy Environment for your fish because the bacteria will eat up all the bad stuff your fish gives out. now your will have to monitor these Ammonia, Nitrate,Nitrate, and Phosphate levels with a test kit., and simply test everyday until you see the levels go all the way down to 0% once you see that all dropped all the way down then your tank has successfully gone through the Nitrogen Cycle and only then it is safe to start introducing fish into your new tank, as this procedure (Nitrogen Cycle) is only needed if you are setting up a brand new tank that is fresh out the box(if ordered online) or fresh out the pet store.

I normally used Seachem Stability as my default bacteria treatment for new tanks and as refresher doses. But in my city, both the pet shops nearby have stopped selling Stability or it's only sold in tiny little bottles. Even AMZ seems to be spotty on when they can provide or will ship it. So I needed to find a suitable brand to substitute that I can get quickly. Since most of my tanks are Fluvals with fluval filters, I decided to try this Fluval Cycle.While its difficult to actually verify any measureable level of beneficial bacteria, I am judging by my experience and Nitrogen cycle readings. I setup from scratch a Fluval Flex 15 and used this cycle to put beneficial bacteria into the filter material. Within 12 hours later, I half stocked the tank with nano fish. The nitrogen cycle progressed much more quickly by using this product than it would have without. I gave the tank the 4 doses over 3 days as the label specifies. The fish and plants in that tank now a week later are doing fine. The Ammonia and Nitrites are at 0 and the Nitrates are low according to my API master test kit. The plants and every other week water changes will likely handle the remaining Nitrate levels.I also did a major (50%) water change in my Fluval Flex 32.5 and doped both filters with a maintenance dose of Cycle. There was no fluctuation to the Nitrogen cycle at all except the already low Nitrates went down due to the water change. My plants tend to consume the excess Nitrates to keep low levels of Nitrates in my tanks. No adverse effects of using Cycle on this tank.I also gave another of my Fluval Flex 15s a maintenance dose of Cycle and all went well there with no adverse effects.I'll use this on my other tanks when their times to do water changes come due and update this review if any adverse effects are noted.So it looks to me like Fluval Cycle is every bit as effective as my default Seachem Stability. But it takes double the quantity of Cycle to do the same as Stability in both 500ml bottles. So its a bit cheaper to purchase Stability due to dosing amounts. No adverse effects have been noted with Cycle.There is one minor annoying thing about the bottle of Cycle. The plastic wrap that surpunds the entire bottle including the lid and cap are a real bugger to break open and peel. Its thick plastic film and stretches and is difficult to get started tearing. It has a seam but trying to break the seal free by hand is very difficult. I had to use a sharp exacto knife to get it open. Then it doesnt peel evenly and I had to keep scoring it in places to remove enough away from the lid. The product expiration date is gone as soon as this plastic is removed. This plastic is also part of the product label and instructions. Do tear carefully or you'll end up removing the instructions too. This really was apparently just to hold the little measuring cup down as there is yet another stuck on seal under the cap to prevent leaks.Good luck trying to read the horribly transparent measuring lines on the little cup. They are almost invisible. I dont like having to spend several minutes just to gain access to the bottle contents (1st time opening only) then to not be able to see the measuring labels on the cup clearly at all. Also the instructions on the bottle label use a tiny little font I cant read without a magnifying glass.Fluval/Hagen needs to rethink their packaging/labeling. But the product works well. I will likely use this Cycle as a substitute brand when I cant get what I normally purchase.