Fishless Cycle Failure

[Rhinox]

Hey MFK. Long time lurker and admirer here. I particularly enjoy reading build and setup threads and like many aspire to have a monster size tank of my own some day. Although, my interests are more in the mini monster african cichlids.

I'm trying to fishless cycle a sump for a 125g double corner overflow tank I've had in storage for nearly a decade. I've been trying to get the cycle going for 40 days now and it's just not happening. I'm looking for some opinions or differential diagnosis on what might be going wrong. Up front, I have not used any bottled bacteria product and haven't sought out cycled media to seed with - maybe that ends up being the answer but I'm not understanding why it's not cycling on it's own by now.

Water parameters:
pH: 7.6
KH: ~5d (it has gone up a drop or 2 due to evaporation and top offs)
GH: ~8d
Chlorine: 2ppm out the tap and no chloramine. Chlorine gassed off within the first 18hrs and was no longer detectable in the sump.
Temperature: ~84F

Media and equipment:
Sump tank: 40 breeder, about 3/4full
Pump: Simplicity 2100DC outlet through 10' of 3/4" vinyl tubing
Initial Media setup: 4" 20ppi poret > 4" 30ppi poret > 300 1.5" bioballs > 4" 300ppi poret
Recently I took out the bioballs because even in the mesh bag they came with they were too much of a hassle when I started moving stuff around. I replaced them with a bunch of old aquaclear sponges to fill the space. I may reintroduce the bioballs later if I build a rigid eggcrate box for them or something, to make maintenance easier.
This weekend I added three 4" puck style airstones in the outlet chamber in case oxygenation was an issue (somehow, despite the high turnover)

Process:
April 18th: added 1ppm ammonia (austin's clear ammonia brand, considered safe to use, no bubbles when shook). Did not add more after.
After March 25th: started testing for nitrites. Expected to find them by March 31, day 14.
(observation: noticed ammonia concentration dropping despite no nitrites. By day 18 it was pretty much gone/trace. No nitrites and no nitrates. It just dissipated. I saw this before when fishless cycling and in the past added more ammonia to compensate, though this time I did not until...)
April 4th-6th: Added ~2ppm ammonia per day for 3 days. Have not added ammonia from the bottle since.
~April 6th: started supplementing with some old fish food, NLS grow, that is a decade old and I wouldn't feed to fish but presumed would be fine for cycling with. I've dumped in maybe half a 2L bottle cap dose of food maybe half a dozen times since then.
(observation: started noticing some organic films growing during the next couple weeks. A white flakey film was growing on the outside of the vinyl tubing. I rubbed it off to let it move to the media. A brownish film started growing inside the vinyl tubing, looking more like how I'd expect biofilm to look. Closer to 2 weeks after upping the ammonia and adding food, I found a thicker biofilm growing on the heater and wires near the pump. I scraped some of that off with my fingers, about a teaspoon, and planted it directly in the filter foam. All this led me to believe I was getting close and would soon get the critical biomass needed to eliminate the ammonia and start seeing nitrites.)
Today, April 26th, Day 40: Still haven't seen the nitrites. Ammonia looks between the 4ppm and 8ppm blocks on the test card but it's hard to tell once it gets that high, and with the food I've been adding I don't really have control on the concentration anymore. Another observation I found is that if I raise the outlet above the water level (or now, with the airstones) the water bubbles at the top and looks sudsy. Naturally I suspected some kind of soap made it in but the bubbles dissipate so quickly and don't feel soapy so I don't really know what to make of them. I try to scoop them out and they just disintegrate.

I haven't done any water changes, just occasionally added top off. I haven't dechlorinated the top off but I let it set for a little while first. Last time I did a test, by the time the top off water went in it was only testing like .25ppm chlorine and after adding 4 liters of topoff I could not detect any chlorine in the sump. So I don't think I'm nuking the BB when I top off.

I don't have many ideas left. I can dump all the water and refill in case there's something in the water stunting bacterial growth. I've been trying to hold off on that in case it's been close to happening so I don't end up disrupting things enough to reset the clock (but if there currently is no clock what am I hurting?). I can thoroughly rinse everything and for sure be starting over. I can give up and try some kind of bottled bacteria or start asking around for some filter squeezings.

Basically I'm stumped at why the cycle is just not happening for me and asking the MFK community for help. Why am I just not able to get a cycle going?

 

[Rocksor]

Any plants in the tank?
So is the chlorine degassing in the tank or some other container?

 

[Rhinox]

Any plants in the tank?
So is the chlorine degassing in the tank or some other container?

Thanks for the reply!

No plants. It's just the sump by itself, not even hooked up to the main tank yet.

When I first filled it up I let the chlorine gas off in the tank. Tap tested 2ppm chlorine. I filled the tank from cold water from an outside garden host spigot so I left it for ~18hrs to heat up before doing anything. When I tested for chlorine then, it was not detectable. That's when I tested the rest of the water parameters and then started adding ammonia.

I've topped off 2-4 liters at a time without dechlorinating the top off water. I usually leave it sitting around a couple hours before topping off. I did a test 1 time and measured about .25ppm chlorine in the top off water when I added it. After adding the 4 liters off top off in to the ~30gallons in the sump, I could not detect any chlorine in the sump with the test strips. It just gasses off so quickly once it leaves the tap. I've only been topping off once or twice a week tops.

 

[Rocksor]

I'm thinking there's just enough chlorine in the water to stop the cycle from starting (even though the test strips don't show any). With cycled tank, it's probably not an issue with how you handle the chlorine.

Are you using test strips for ammonia and nitrite?

 

[dogofwar]

If you have another tank... or know someone who does... just grab some media from it or squeeze out a sponge or two into the new tank. I keep extra sponge filters running in a couple of tanks for this purpose.

 

[Rhinox]

I'm thinking there's just enough chlorine in the water to stop the cycle from starting (even though the test strips don't show any). With cycled tank, it's probably not an issue with how you handle the chlorine.

Are you using test strips for ammonia and nitrite?

Strips for chlorine only, API drops for everything else (picked up a fresh master kit as my old one from years ago was long expired, as well as the KH/GH drops as well).

I've been suspecting my top off water on and off. If that's what the issue is definitely shame on me for not correcting it sooner. If my topoff water was always .25ppm chlorine and I add 4L it should theoretically raise the chlorine level in the sump to about .01ppm. If I hit it with the full tap concentration, then it'd naturally end up 8x greater, .08ppm. Since I can't detect down to those levels anyways, I don't know how long it takes to totally degas on it's own and have no idea if that hit of chorine once or twice a week is toxic enough to prevent the cycle from happening. I've read and been told elsewhere it wasn't but maybe my lack of cycle is evidence to the contrary.

When I'm all set up with the continuous drip water changer I plan to use a carbon refrigerator filter on the inlet line to remove the chorine. But I'm only going to be running like 1-2 gallons per hour in to a ~150 gallon system so that's probably unnecessary. Mostly just there as a safeguard against some unexpected change or surge in tap water parameters. So not really planning on needing to have dechlor around but no reason I can't go track down some sodium thiosulfate and treat my topoff water. Probably a good idea to have some on hand anyways incase I have to set up another tank in a hurry.

If you have another tank... or know someone who does... just grab some media from it or squeeze out a sponge or two into the new tank. I keep extra sponge filters running in a couple of tanks for this purpose.

I haven't had a tank up in about 8 years so I'm starting from scratch. Don't know anyone nearby with a tank. I'd have to resort to cold calling on my neighborhood social media page maybe. I haven't become desperate enough to ask yet. My brother has a couple tanks with aquaclear sponges but he lives 3 hours away.

 

[Cich Mind]

Hello R Rhinox ,
I would check some local LFS to see if you can get some seeded/used gravel from one of their tanks. I have an LFS that can do that for me. It jump starts the nitrogen cycle. There is also a product called Stability by Seachem that is bacteria in a bottle that many people swear by. Either one of these choices would make cycling much easier and quicker for you. GL

 

[duanes]

To me, most new cycles (especially with new unused tanks) average at least 2 months to fully complete.
At 40 days I wouldn't expect to see nitrate (just some nitrite).
At 80 days is when to expect nitrate start to climb.
If you plan to plant (aquatic plants).....why not do it now? The plants can help speed up the cycle

 

[pacu mom]

It would really help to seed the tank liberally (as in dump in a lot) with a biological additive like Dr Tim's One and Only or one of the others out there. It is recommended to add ammonia to 4 ppm. You will find that the ammonia consuming bacteria colonize pretty quickly, and the 4ppm ammonia will drop to 0 ppm in less than a day. Keep adding ammonia back to a concentration of 4ppm. As soon as there are measurable nitrites, add ammonia to a concentration of 2 ppm. It might take several weeks to colonize the nitrite consuming beneficial bacteria, so be patient. It will happen. While slower to colonize, this group of bacteria is hardy. While I have had ammonia spikes (power outage and/or gross overfeeding), I have never had measurable nitrites once the tank was cycled.

I recommend using only the pure ammonia which you can measure, and not throwing in other stuff which will break down and create a cesspool. You can't measure the ammonia concentration by throwing in random food items.

Even with liberal dosing of biological additives and keeping ammonia to 4ppm, it still took about 45 days to cycle my tank. Patience is required to fishless cycle. The beauty of fishless cycling to 4 ppm ammonia is that there will be more than enough beneficial bacteria to handle the bio load of the fish which will reside in the tank.

 

[dogofwar]

Fish store close?

Strips for chlorine only, API drops for everything else (picked up a fresh master kit as my old one from years ago was long expired, as well as the KH/GH drops as well).

I've been suspecting my top off water on and off. If that's what the issue is definitely shame on me for not correcting it sooner. If my topoff water was always .25ppm chlorine and I add 4L it should theoretically raise the chlorine level in the sump to about .01ppm. If I hit it with the full tap concentration, then it'd naturally end up 8x greater, .08ppm. Since I can't detect down to those levels anyways, I don't know how long it takes to totally degas on it's own and have no idea if that hit of chorine once or twice a week is toxic enough to prevent the cycle from happening. I've read and been told elsewhere it wasn't but maybe my lack of cycle is evidence to the contrary.

When I'm all set up with the continuous drip water changer I plan to use a carbon refrigerator filter on the inlet line to remove the chorine. But I'm only going to be running like 1-2 gallons per hour in to a ~150 gallon system so that's probably unnecessary. Mostly just there as a safeguard against some unexpected change or surge in tap water parameters. So not really planning on needing to have dechlor around but no reason I can't go track down some sodium thiosulfate and treat my topoff water. Probably a good idea to have some on hand anyways incase I have to set up another tank in a hurry.


I haven't had a tank up in about 8 years so I'm starting from scratch. Don't know anyone nearby with a tank. I'd have to resort to cold calling on my neighborhood social media page maybe. I haven't become desperate enough to ask yet. My brother has a couple tanks with aquaclear sponges but he lives 3 hours away.