Fishless Cycle Seems To Have Stopped Eating Ammonia

I have two 10 gallon tanks I'm trying to cycle. It's been about 2 weeks and things were going well. I've been using Dr Tim's pure Ammonia and following their fishless cycle instructions. I dosed it up with 4 drops per gallon and got to the point recently where after 24 hours the ammonia would be essentially gone and I'd dose it with another 4 drops per gallon (40 drops total).

The past few days, however, the ammonia is no longer gone after 24 hours. One tank yesterday was really low at 24 hours but the other was not. Then today the one that was low after 24 hours is now not low after 24 hours. Both tanks are off the charts on nitrites and nitrates. But why have I gone from the bacteria being able to eat all the ammonia I add in 24 hours to still having a ton of ammonia after 24 hours?

 

Did you add more ammonia than normal? Or did you add more ammonia sooner than usual?

 

No, I've been following their instructions here: A Quick Guide to Fishless Cycling | DrTim's Aquatics

Each morning I measure the ammonia and if it's < 1ppm (which it has been every morning for the past 4 or 5 days before this) I dosed another 4 drops per gallon. That worked fine for days and the next morning the ammonia would all be gone, until yesterday and today.

 

So one thing I found... My PH seems to be super low, like 6. Which is weird because my tap water is like 7.8. How the heck did it drop so much? One of the tanks is just a filter and gravel...

Would the low PH stall the cycle? Should I do a water change to bring the ph up?

 

Low PH indicates a drop in KH (carbonate hardness), which can definitely stall a cycle. Add about a tsp of baking soda (bicarbonate, NOT baking powder) to get the KH levels back up. If you do not have a gh/kh test kit, then check to make sure that gets your PH back up.

You also said your nitrites were off the charts. A very high nitrite level can stall a cycle. That can be handled with a water change.

 

If your ph is low then it may have become ammonium instead, though I know nothing about ammonium as my ph is 8 and I have never had to deal with it.

 

So the KH was yellow on the first drop. Which is definitely lower, tap water takes like 4 drops. Come to think of it last week it seemed like it stalled slightly but then bounced back and I realize I topped up the water that had evaporated. Maybe I just need more frequent partial water changes while cycling.

 

You have to keep your nitrites in check. When they get too high, it throws things out of whack. Only do water changes when that happens because you don’t want to knock your nitrates down with too frequent water changes.
A little bit of baking soda and you should be back in business. Then just keep nitrites from going off the charts again.

 

I thought you wanted high nitrites to grow the bacteria for those and it was high nitrates you had to do water changes to keep in check? I mean I've got high both so... I did a 50% water change in both tanks and now the ph and kh are good again, will keep an eye on it and hope it finishes cycling soon...

 

High nitrates will not kill your cycle. High ammonia and nitrites will. You just need to keep them under 5ppm.

 

Because nitrates are far less toxic than nitrites and ammonia, the concept of "high" is relative when talking about these things.

1 PPM of ammonia is High to me whereas 10 ppm nitrates is not high because it is about a hundred times less toxic

 

HI there. So some of the info people have given is okay. Some is not exactly right.

So you are adding WAAAYY too much ammonia first of all. These are only 10 gallon tanks. At the very most you would need to cycle to 2ppm. In no way would you need to cycle to anything higher. This means you only need to do 1 drop per gallon to achieve this. So 10 drops maximum. Too high of an ammonia dose will become toxic and stall a cycle.

Having high Nitrites and high nitrates will also stall your cycle. I would do a 100% water change in both tanks. Then retest in 24 hours. Then add your next dose of ammonia.

Your kH is the measurement of your carbonate hardness. In particular it is the measurement of calcium carbonate in your tap water. Calcium carbonate is also called a buffer. A buffer helps to keep your pH level stable and neutral (or alkaline/pH above 7.0) if your kH is too low, then it gets used up very quickly by the nitrogen cycle. Which is a naturally acidic process (pH below 7.0)

A kH of 1 drop is very low. To have a stable kH/pH it needs to be 3-4 drops. You say that your tap is 4 drops. For some tanks that is not enough to stabilize. When it gets used up, your pH will plummet.

There are easy ways to solve this issue. I however wouldn’t use baking soda (bicarbonate) as a long term solution. It will help raise your pH and kH temporarily. But will need to be added more than once a week to stabilize anything. Instead you should add calcium carbonate. You have to choose which way you want to do it. There is the precise, once a week with water changes, or the not so precise, once a month method.

With using a pH upping product, such as Seachem Alkaline Buffer, you will Test your kH and add a precise dose to raise your kH to whatever you are going for. If I was you I would go for 5-6 degrees. So you would want to raise it by 2 points from your tap water. This would be done each week with water changes.

Now if you want to do the easier, non-precise method you would pick a solid buffer to work with. Crushed coral, cuttlebone, aragonite, limestone, seashells, or Texas holey rock. You can use it as a decoration, or put it into a media bag, and place into the filter. For Crushed coral, the dose is 1/4 cup per 10 gallons. Put into a media bag, and add to filter. In 24-36 hours your pH will stabilize. It may take a little longer for your kH to raise. Usually your kH will stabilize around 6-ish and your pH will stabilize between 7-5-8.5. You will need to replace the crushed coral about once per month when it gets used up. Less control, but much less work.

While doing the water change, you can also add whichever pH upping product you want. This will give it time to raise your pH and your cycle will again be back on track. A crash in your pH will indeed stop your cycle, and may even kill off some of the bacteria. So it is important to get this taken care of also.

 

In my experience with cycling, if the kh and ph are good out of the tap and a drop occurs, it is due to overdosing ammonia like alliesten said. In that case, the quick fix of bicarbonate gets the levels and the cycle back on track and you will likely not need to use other means to elevate kh or ph. Sounds like a water change did the trick for ya.
Using buffers, etc is not recommended unless your water source is really low or for specific fish such as African cichlids that need high ph. That is because it is better to have low consistent ph than to have swings. If you go that route, it is critical to stay on top of it like recommended to change out every week etc. Crushed coral has worked well for me in cichlid tanks to bump the ph a bit.
I do disagree that high nitrates will stall a cycle. I have had it off the charts cycling many many tanks and never stalled. I wait for the cycle to finish before performing large water changes to get it down. Having said that, a partial water change is ok to get your level down, but nitrates are in the water column so 100% may kill your cycle leaving too little to handle nitrites resulting in a huge nitrite spike.

 

My PH is stable in my main tank. I assume the PH and KH dropped due to the high nitrates due to cycling so I don't think I require any long term stabilization. I did a 50% water change in both tanks yesterday, and a 90% today. That brought the PH and KH back up. Ammonia is back to going away like crazy. I dosed 30 drops in each tank this morning and it's now down to 0. I added another 20 drops tonight. I'll try to dose it less but it's eating the ammonia so fast I'm going to have to add it 2 or 3 times a day with a lower dose... Nitrites are up but not turning instantly purple anymore.

I feel like at this point I need to do 50% water change daily, and if I dose less ammonia I'm going to have to add it more frequently. I mean if it can eat like 3ppm ammonia in 10 hours... Why the heck won't it eat the nitrites that fast?!?!?! But I have to keep dosing it right? I'm worried if I leave the tank with low ammonia for too long I'll stall out again. I'm going on 3 weeks here and I saw nitrites and nitrates within the first week so I'm getting a little frustrated!

 

You only need to dose every 24 hours. Patience is key in cycling. It is normal to have nitrite once ammonia starts processing in 24 hours. That means your cycle is progressing nicely. Ammonia is handled first, then nitrites as the bacteria grows.

If you change out too much water, it will take longer for nitrites to start processing because you are removing the bacteria that eats it, nitrates. 90% change is going to knock your nitrates too low to handle the nitrites that have built up in your filter media.

 

You only need to dose every 24 hours. Patience is key in cycling. It is normal to have nitrite once ammonia starts processing in 24 hours. That means your cycle is progressing nicely. Ammonia is handled first, then nitrites as the bacteria grows.

If you change out too much water, it will take longer for nitrites to start processing because you are removing the bacteria that eats it, nitrates. 90% change is going to knock your nitrates too low to handle the nitrites that have built up in your filter media.

Nitrates don’t handle nitrites. Not sure what you mean by this.

The second half of the cycle where the bacteria that converts nitrites to nitrates is slower growing. You may need to do daily water changes at this point to keep the nitrites low enough. The more ammonia you add, the higher the nitrites and nitrates will be. As long as your nitrites are below 2ppm and nitrates are below 80ppm you shouldn’t need to do a water change. But anything above that, you should do a water change to keep the cycle going.

 

Currently 24 hours after a 90% water change my nitrites are probably 2-5ppm (really hard to tell the shade) and nitrates are 80-160ppm. Going to keep up with water changes and start dosing less ammonia and see how it goes.

 

Well I think one tank might be ready! Last night nitrites were pretty purple, did a 50% water change and still purple, then dosed with 20 drops of ammonia chloride. This morning ammonia and nitrites are both at 0!

Going to dose it with another 20 drops and if there's no nitrites tomorrow then my daughter can finally get her beta, she'll be so excited. The other tank is still pretty purple on nitrites so not quite ready yet but hopefully soon.

 

If you are dosing 20 drops per day, and it's all going to nitrates, that should support more than one betta for sure.

If you could get a young male and a young female they might have some fun in that tank.

But if they're mature they might not get along.

 

Yeah I don't know if I want to mess around with multiple bettas! I was thinking of either doing some amano shrimp or some pygmy corys (if I could find any). A small tetra might be nice too but 10 gallons seems a bit small for a betta and a school of tetras to keep away from each other.