New tank Cycle Question.

hoopzers3

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Hey all, This is actually my first post on Reef2Reef! I have been a lurker during my whole setup process so far. I have a question about the initial cycle. Just want to make sure things are all progressing well. Firstly, here is the setup,

Tank - 15 gallon IM
Rock - Dry rock from Marco
Sand - Live sand from Carib-Sea reef
1764700328044.png



I am going for a fish free cycle using both BrightWell Microbacter quickCycle and its Brightwell Micrboacter Start XLM products..

I will go ahead and post a picture of all my testing so far in my first 14 days so far down below... As you can see I started the cycle on November 19th. Got Ammonia up to 2 and added the Start XLM. My ammonia got down to the .25-.50 range with the API tester (which i know can be annoying and usually doesn't hit 0) about 9 days into the cycle. Once I didn't see the ammonia change for roughly 4 days in a row and saw that I had nitrates at 20-25 range.. I went ahead and dosed the ammonia to 2 PPM again for the (24 hour test) that I have read about. SO, today 24 hours later Im getting a reading of about 1-1.5 ammonia and nitrates up a tad more to 25-30. What do you guys think I should do now as that 24 hour test seems to have failed.

Also, is it weird i never "officially" got any Nitrites in my testing? I heard that happens sometimes?


Screenshot 2025-11-30 090333.png



Thanks so much! And once again, glad to be apart of the Reef 2 reef community officially :)
 

lapin

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Let the ammonia go down over the next few days. Since you have nitrates , the tank is done with the basic cycle. Once ammonia is gone , change out 50% of the water. You don’t want to start with high nitrates . No need to feed the algae. You should be good to go.
 
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hoopzers3

hoopzers3

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Let the ammonia go down over the next few days. Since you have nitrates , the tank is done with the basic cycle. Once ammonia is gone , change out 50% of the water. You don’t want to start with high nitrates . No need to feed the algae. You should be good to go.
Awesome, thanks for the feedback. I’ll let the ammonia continue to drop in coming days and update.

In regard to the 50 percent water change.. is that a lot to do after this cycle/so early on? I’ve read and researched that 20-30% is what a lot strive to do. I guess it does depend on my nitrates right? Just don’t want to take out too much of the “good” bacteria that’s in there being it’s such a brand new tank with dry rock and sand… But if 50 percent is good I’ll go with that!

Thanks
 

lapin

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The bacteria live on surfaces . Very little will be in the water column. 30% will work also.
 
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hoopzers3

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Just a little update, 24 hours later on.. Looks like Ammonia and Nitrates stayed roughly the same as yesterday testing. So Ammonia in the 1.5-2 range and nitrates roughly around the 25ppm range. So 48 hours after dosing the Ammonia up to 2 seems to be no change since than...

Can confirm the 24-48 hour test of 2nd dosing of ammonia to 2, after the initial 2 - 0.25 ammonia after 2 weeks in is not happening yet :(

Patience game is in play as I see on other posts. Surprised there wasn't any move though in 48 hours for my 2nd dosing of ammonia.

So my guess is the bacteria in the tank are still a little slow and there isn't a bigger issue going on! haha
 

Skippy The Meh

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the nitrogen cycle goes different for everyone to start. dont be afraid to add some more beneficial bacteria. sometimes it takes some time or a couple doses to really get it established. good job staying patient and not throwing in fish and or turning on the light. what testers are you using?

also keep us updated as you go along on the build!
 
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hoopzers3

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@Benji. Yea, I was thinking about another cap full of bacteria or so?.. Strange as they got the ammonia down early in about a week, than I waited a couple days before this test, but now struggling to do it for this quick Ammonia killing test.. Can you over add bacteria (using the Brightwell Start XLM)?

As far as testers, The Ammonia and Nitrites are on API... And the Nitrates I'm using Salifert.

Staying patient is key! Definitely wont throw in any fish until its ready :D
 

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Patience is the fleeting virtue of red keeping. Is tough to wait on nature to do its thing but I can tell you from experience you won’t regret it later! While you have live sand, it probably isn’t as much as you have of dry rock, and things take longer with dry rock (and dry sand) to fully cycle. Give it a couple more days and then test again. Don’t frustrate yourself testing every day. Even wait a few days. Ditch the API because they are horrible. Get Salifert (or Hanna) for more accurate results. Nitrites have no toxicity in saltwater so ignore them as nitrates are already present and monitor as you have been.
 

Skippy The Meh

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@Benji. Yea, I was thinking about another cap full of bacteria or so?.. Strange as they got the ammonia down early in about a week, than I waited a couple days before this test, but now struggling to do it for this quick Ammonia killing test.. Can you over add bacteria (using the Brightwell Start XLM)?

As far as testers, The Ammonia and Nitrites are on API... And the Nitrates I'm using Salifert.

Staying patient is key! Definitely wont throw in any fish until its ready :D
Ya definitely at least a cap full, you cannot technically add too much bacteria to a tank. however this is my hypothesis:

bacteria eat ammonia to live (in the case of a new tank). if they don't get enough ammonia they die. if you just dump a whole bottle in the tank, all of the ammonia will be gone very quickly, thus satisfying your 24 hr test. however, not all of that bacteria will live, in fact most of it will die. in an established tank bacteria thrive because of all the things decomposing, so the population thrives, coating everything in the tank including the glass and piping and fish. with a new tank you are temporarily giving the bacteria their food source until the tank is established. so the population of bacteria can vary drastically day to day, thus massive tank condition swings we see in new tanks. all this to say, in my opinion, a balance between your ammonia source, and your beneficial bacteria source is key. if you have a friend or a LFS that has quality, established live rock and will give you a piece, this is the best way to cycle the tank. it will be night and day difference. also trying different bacteria works for some as well, Dr. Tims is a popular one to try.

if you have the money, invest in hannah checkers, you will not regret it. it will save so many headaches of inaccurate tests. i have the hannah marine master kit. its just one photometer for all the parameters. it does become a pain however when i need to check all my parameters, it takes extra time. the individual checkers work good too.
 
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hoopzers3

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Thanks both for the responses. Is it generally a good idea to do a 2nd dose of ammonia to 2? I ask this cause from my testing my ammonia was .25-.50 and nitrates at 20-25ppm after the first week(7days)... Which is what Brightwell says is good on the instructions. Was my tank technically cycled at that point? I'm worried i prolonged the cycle for no reason with this 2nd dose of ammonia which was maybe silly of me?... I just thought it was a general rule of thumb to do that 24 hour 2 to 0 ammonia test. I am just doing it to be extra cautious before adding in a fish.
 

Skippy The Meh

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your doing the right thing. better safe than sorry. i would keep the cycle going until you consistently can add ammonia and tank goes to 0 shortly after. your fish will constantly be producing waste on top of extra food and other stuff decaying. if the bacteria colony is not well established the tank can become toxic quick
 

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Can you over add bacteria (using the Brightwell Start XLM)?
Yes, you can for two reasons:
These bottled bacteria products don't usually include the true bacteria that will eventually be the biofilter in your tank. These bottled products typically contain a fast growing heterotrophic bacteria that can use ammonia as part of their metabolism, but they are not the autotrophic bacteria you really want. Think of these bottles like a bad aid, not a long term solution. Adding too much at this time can allow the bottled bacteria to outcompete the autotrophs that take some time to develop.

And, adding too many bacteria from bottles can lead to large blooms of bacteria that can rapidly deplete the oxygen in the system, which can be fatal if/when you have fish and other livestock.

I wouldn't add anything more, except time 🙂

You have all the bacteria you need, just let them grow. You have all the ammonia that you need, there's no need for repeated "testing", which just results in excessively high nitrate in the end, often necessitating a large water change. Once you see the ammonia concentration go back down to about 0.25 ppm on the API ammonia test, I would then start to slowly stock some hardly livestock.

Don't worry about nitrite, it's non toxic in marine systems (unlike freshwater). However; nitrite when present at this time will cause an artificial high result for nitrate testing. For that reason, you can't know your true nitrate concentration until the nitrites have gone to zero. I wouldn't bother to test for a true nitrate result for another couple of weeks or so.

I hope that helps and good luck!
 

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the actual test is dose ammonia to 4 ppm should be zero 24 hours later Nitrates are for you to deal with later water change skimmer ect lots of approaches there. As said you cannot flush the established bacteria out. Its in the rock as stated. You never said anything about lights . if they are on your tank should be pretty messy by now. If not it will be when you do. That's the so called ugly stage. Don't panic and start doing all sorts of things. It will settle down. My 100 plus sump of 4o took me 40 days . I wanted to be absolutely sure. Throughout the process I dosed ammonia practically every day
 

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Hi one last thing I would not wait once you are done to add inverts of your choice. My favourite is snails. Especially Trochus. They never sit still terrific cleaners of rock ect. Also I have Bumble Bee and Nassarus snails that hide in the substrate and are hopefully eating your left over fish food ect. Others seem to like shrimp and different fish for clean up, which I have never had . I did like my Diamond Goby sand sifter. It made a mess sometimes because they like to burrow but its grumpy face was too funny. My Bully Tang chased it out of the Tank. I sincerely wanted to flush the Tang they have unpredictable personalities and grow fast. I will never get another yet it seems some people choose them first
 
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hoopzers3

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Hi one last thing I would not wait once you are done to add inverts of your choice. My favourite is snails. Especially Trochus. They never sit still terrific cleaners of rock ect. Also I have Bumble Bee and Nassarus snails that hide in the substrate and are hopefully eating your left over fish food ect. Others seem to like shrimp and different fish for clean up, which I have never had . I did like my Diamond Goby sand sifter. It made a mess sometimes because they like to burrow but its grumpy face was too funny. My Bully Tang chased it out of the Tank. I sincerely wanted to flush the Tang they have unpredictable personalities and grow fast. I will never get another yet it seems some people choose them first
Great! Yes I am looking to add 2 small clown fish, and some Nassarus/Trochus snails. Seem like a pretty good setup at first as things get going. :D

Than some coral a couple months down the road!

As far as lights, I know someone asked me, I have a Nicrew 65 watt light that I haven't turned on yet during the process so far. Besides an hour or 2 here and there, (as i couldn't resist seeing the tank glow for a bit) But overall, no light cycle they past 2 weeks :D

With regards to the light, when is it recommended to turn them on (how many days before CUC and fish arrive) to start growing some food for them... Is turning lights on instant ugly stage/aglae? In about how many days in advanced, once i turn them on? I know this varies so hard to answer 😂 But if anyone has a recommendation on when to turn on lights so they don't starve once they arrive. But, I also have read that even if it doesn't look like snails have food in the tank (algae, ugly stage) etc... there still is stuff they will find to eat.
 

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Great! Yes I am looking to add 2 small clown fish, and some Nassarus/Trochus snails. Seem like a pretty good setup at first as things get going. :D

Than some coral a couple months down the road!

As far as lights, I know someone asked me, I have a Nicrew 65 watt light that I haven't turned on yet during the process so far. Besides an hour or 2 here and there, (as i couldn't resist seeing the tank glow for a bit) But overall, no light cycle they past 2 weeks :D

With regards to the light, when is it recommended to turn them on (how many days before CUC and fish arrive) to start growing some food for them... Is turning lights on instant ugly stage/aglae? In about how many days in advanced, once i turn them on? I know this varies so hard to answer 😂 But if anyone has a recommendation on when to turn on lights so they don't starve once they arrive. But, I also have read that even if it doesn't look like snails have food in the tank (algae, ugly stage) etc... there still is stuff they will find to eat.
To me turn on lights now the ugly stage will start very fast like I said don't Panic it will resolve itself do not add any treatment. you can add snails right away then. You should se the rock change colour. The snails will have lots of food then. As to fish I waited until all of that was over. You should ask others to get opinion on that if your in a rush. I know a lot of people just dump them in any old time . I always do things one at a time and if I see a problem then I know exactly where to start. I again unlike some used a Par meter when it came to adding Coral. Again I waited quite a while. Your light ie Par will let you know what type of Coral you can keep LPS ( Large Polyp ) need around 80 to 150 from what I read SPS ( small polyp ) need quit a bit more up to 450. You used to be able to rent a Par metre from Bulk Reef Supply. Mine is an Apogee and is expensive but I use it quite a bit Back to fish I took a chance by buying 7 and adding them to the main display . It worked for me I just used another members method who was Paul B he carefully visually inspects them . Others swear by Quarantine. There are articles on this site for that. I lost one fish trying to Quarantine. It just would not eat went into a funk and died which is why I did what I did. That decision is yours to make. In the articles section search for " Current Quarantine Protocol " The Bumble Bee snails are really good for eating any extra food and you will rarely see them as they burrow. Your Clowns will fight for Dominance and one will remain small and change to Female I recommend a cover or it may get chased right out of the Tank. Be sure to have a place for it to hide it gets pretty violent. Expect the larger one to bite you if you put your hand in the Tank. Mine still surprises me sometimes. It did draw blood once. Where vinyl gloves lol
 

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