Can't get tank to cycle!

[edgellj]

I bought a Fluval Edge (6gal with a "standard" fluval filter rated at 20gals) about six months ago. To do the initial cycle, I added about 10lbs of rinsed sand (just under 2"), a couple small decorations and about 8 (very) small feeder goldfish. After about two-three months, the tanks' nitrogen cycle was very stable, and the goldfish retired to the rain barrel outside to live a comfortable life eating mosquito larvae.

I then decided to put in a gourami and three cory cats, with the expectation that if the cories or gourami ever outgrew the tank, I'd move them to another. At the time, the gourami was about 2" and each of the cories were about 3/4", so I felt safe that I was well under the "one inch of fish per gallon" rule.

I vacuumed (as well as one could) the sand weekly and did about 1/3 water changes (it is VERY hard to move a vac around this tank). Then, out of nowhere, I wake up one morning, one of the cories is dead and the gourami has little brown lesions all over his head.

I check the tank: no nitrites/nitrates, a pH of less than 6.2 (the lowest my kit will read - the kit reads in shades of yellow, green and blue, but this was a paler yellow than the lowest reading), and ammonia at greater than 8.0ppm (higher than my kit will read - my kit reads in shades of yellow and green and this was navy blue). I freak out.

I stirred the sand (to get what waste I could floating in the water) and do a 50-60% water change. I go to rinse out the media in the tank water and notice that it's gone from slightly brown (as it had been the past 3+months) to pink and the sponge has gone from slightly brown to blood red. Yes, I've changed my sponge and media once every two months, per package instructions, this was in the middle of the second sponge/media combo. I tossed the sponge and media - they aren't supposed to be that color!

I get everything back into the filter, add water (I don't need a dechlorinator because my water is filtered and has perfect readings across the board) and add Neutral Regulator to put back some of the calcium and magnesium that my water filter takes out. I drop in about 3/4tbsp aquarium salt to help the chemical burns on the gourami and the obviously suffering cories. After about two hours, the gourami has calmed down and the cories are back to doing cory things.

The next morning, I wake up and I walk past my tank and catch a whiff of what I thought was windex. I check the readings again, and again we're above 8ppm on amonia, but today the pH is ok. I do a 30% water change and get the ammonia back down to ~4ppm. This continues day after day with wildly fluctuating ammonia and pH readings. Ammonia is always too high, pH is almost always too low. I'm heading to the lfs every two or three days for new chemicals, new bacteria, you-name-it.

Finally, I decide that, although I really like the guy at the lfs, I start consulting google because daily water changes CAN'T be good. I start reading about buffering capacity and look at the areas of my test strips I've never really paid much attention to, and realize that, well, my tank has no buffering capacity, despite adding Neutral Regulator at every change. I order (because the lfs doesn't cary) crushed coral from Amazon. I rinse everything out, mix it into the sand and we have no more wild pH swings. I do some more research on the ammonia problem and I run across "Zeolite" and "AmmoLock". I order both, figuring one will do if the other doesn't. Boy, was I wrong.

The Zeolite completely ignores the ammonia in the water, in stead dropping overall Alkalinity (apparently it prefers calcium to ammonia) and AmmoLock's effects never last more than a few hours. No nitrites. No nitrates. Ever.

Fish are only getting food every other day (the gourami has now taken to striking at the top of the tank when I walk by).

After more reading, I came to the conclusion that sand may not be the best freshwater substrate. I siphoned out the tank water, removed the sand, put a mix of crushed coral and gravel (again, just under 2"), removed all decorations (except for one hidey hole for the cories). This was about 4 weeks ago and I'm still having daily ammonia spikes and have never seen nitrates or nitrites in the tank since the goldfish moved out. As well, I've never seen the "brown fog" that was present when the goldfish were there (bacterial colonies in-tank).

I've been doing daily water changes for almost 10 weeks now.

So...here are a couple bits of info about how I'm trying to care for this tank:

1: Inhabitants: one opalescent gourami (approx 2") & two corydora cats (<1")
2: Ammonia: between 4 & 8ppm depending on whether a water change has just been done. Nitrites/Nitrates: 0. Chlorine: 0. Total Hardness: between 250 and 425 (it's hard to tell with my strips). Total Alkalinity (buffering capacity): about 160ppm. pH: stable-ish at about 7.4.
3: 6gal tank. Tank has been set up for a total of 6 months. Currently attempting second cycle due to substrate change.
4: Filtration: 20gal Fluval Edge (came with tank). Recently added additional 6.6gal Marineland in-tank to assist.
5: Daily water changes of between 20 and 50% depending on that day's ammonia reading. Gravel/crushed coral substrate is thoroughly agitated every time.
8: Current fish have been in tank almost 3months.
9: Fish food: NutraMax flake & Hikari sinking algae wafers (small).
10: Chemicals/Bacteria: Neutral Regulator at water changes (the coral seems to make the water a tiny bit more basic than I'm comfortable with for the cories), NiteOut & Stabilizer (nitrogenous bacteria) and Prime. All chems & bacteria added at water change time in amounts recommended on container for amount of water changed or aquarium size.

I know I'm doing too much: my son has a 2L tank in his room that we barely have to touch, except to replace evaporated water every week. The 55 gal in the living room is also perfect. I've even gone so far as to doing water changes from the 55 into the 6gal to try to get things moving. Is my Fluval Edge just haunted?

 

[DeathclawRowe1]

I've had the same problem. I skimmed your post but I had a tank that refused to cycle. After researching I discovered that some times aquariums go through many "mini cycles" where the ammonia and stuff will shoot to 4 ppm sometimes, I would move the Cory's because they are very sensitive fish, the gourami should be moved if possible. I would run the tank for a few weeks to let the ammonia break down to about .5 ppm then re add the fish, when u let the aquarium run don't do water changes. I did that for my 10 gallon for 3 weeks no water change just strait run and it fixed itself. If you have any more questions I'm glad to help

 

[Hbbambislayer]

Water from your 55 isn't doing anything. But that tank can be very helpful. 1st is stop every thing your doing with that fluval tank. 2nd g find a temp home for the fish sounds like you got some space or at least put them in s container so you can do a 100% water change add 2ml of prime to your water. 3rd get something from the 55 not water bacteria doesn't live in the water, some substrate you can put in panty hose or a filter bag and float in the tank some decoration or the best choice is media, pads, balls whatever you can from the filter to seed your little fluval with good BB. Put your fish back in if you can't locate them to another home temporarily check levels every day ammo higher than .25 50% water change same with nitrites until your tank has cycled again. Don't forget your prime after every water change. Id throw all that other stuff in the trash.

 

[edgellj]

Stand back...I'm attempting science!

Unfortunately, the 2L in my son's room and the 55gal are not hospitable places for the fish from my small tank (the 2L is just too small and the 55 gal is a cichlid tank). The gourami might be fine very short term, but the cories are smaller than the feeder fish I buy for the cichlids.

I have a theory that there's something in this tank that's killing the bacteria, so I'm going to use a bit of Special Blend (it's red and super stinky - easy to tell if it's growing) in a mason jar with a sample of the tank water to isolate it from anything that might be happening in the filters or the substrate (or maybe it's some weird stress chemical the fish are emitting).

I haven't set up many tanks in my time, but I've never been two weeks into a setup without seeing nitrates/nitrites and then three weeks without seeing cloudy water and the brown "fuzz" on decorations. But then again, I've never done a "live cycle" with anything other than feeder goldfish.

Thanks for the suggestions.

• I'll try moving a few of the decorations from the 55 gal.
• I'll look into a divider for the cichlid tank if this mason jar experiment yields no results over the next few days.
• I'll try to chemically adjust the ammonia over the next few days (AmmoLock every few hours) with no water changes to make sure I'm not sucking out the bacteria to see if I can get a bloom in the tank while the mason jar experiment is ongoing.
• If I can't get a bloom, I'll try the 100% water change and move everyone to the cichlid tank with the divider and attempt a fishless cycle.

 

[librarygirl]

I suspect it's the PH; if PH drops below 6.5 it can keep the bacteria from doing it's job, thereby allowing toxins to build up. I wouldn't add chemicals to the tank unless it's necessary. Get some crushed coral or crushed aragonite (sold at most fish stores in the saltwater section) and put a teaspoon in a mesh media bag or clean (never washed with detergent) nylon stocking and try to fit it into the filter. Keep testing PH and add/remove coral until you can get the PH to stabilize around 7.

You also may want to test your tap water's PH; test it out of the tap and then let a glass of water sit for 24 hours and test it again. This is your true PH and what your tank's PH should be. If it's higher than the tank's PH, then there's something in the tank that's lowering PH. If it's really in the low 6's then your water is just low on buffers and the coral should help. In the meantime do extra water changes to keep ammonia levels down. Also you might want to add something like Prime when you do water changes to help detoxify the ammonia in the tank until you can stabilize it.

 

[edgellj]

Thanks librarygirl, but I've added about 2lbs of crushed coral with aragonite to the gravel substrate when I tossed the sand about a month ago. The pH has stabilized in the 7.5 range. The only reason I'm trying to lower it now is that higher pH causes Ammonia toxicity at lower temperature and the natural pH for the cories should be slightly lower than that (although it's a struggle because the gourami will want a 7.4-7.8 ...) Should've done more homework on the inhabitants for this tank...

 

[Hbbambislayer]

Doing a water change won't hurt anything your not sucking anything out but the bad stuff from the water no Bacteria Lives in water NONE 0. Get that nasty toxic water out of that tank

 

[Hbbambislayer]

If you don't want to move the fish out of that tank do a 50% water change wait 2 hours or so do another 50% water change and just be be safe wait anther 2 hours and do it again and don't feed them. And library girl brings up very good point what's the ph from your tap.

 

[edgellj]

From tap:

*pH: 7.6
*ammonia: 0
*chlorine: 0
*nitrates/ites: 0
*total hardness (GH): 0
*total alkalinity (KH): between 0 & 40ppm

(I have an amazing filter on my tap.)

 

[Hbbambislayer]

Your tank ph should be 7.6 7.8 unless you have driftwood or certain rocks in the tank you had a huge ph crash for some reason. Please change out the water all of it either in steps or all at once put your fish back in don't feed them if you got something you can steal from the 55 use it test your water tomorrow after 24 hours we can go from there. Don't forget to use your prime with your change or changes. 2 ml each time no matter if your doing 50% or 100%

 

[Hbbambislayer]

Test your water after you change your water your goal is to get it to be exactly like your tap or very very close. Just a little hiccup in the cycle no big deal. Just be prepared today do do a few water changes

 

[edgellj]

More water changes

@Hbbambislayer: Water changes every two hours over about six hours. 50ish percent each time. Prime and NiteOut each time. The fish are frenetic and try to hide every time I come near the tank now. pH still nominal at 7.6 (the crushed coral does it's job pretty well), but now dissolved solids (GH & KH) are non-existent. The ammonia still reads at 2ppm.

Good news on the tank water test front, though. The mason jar has actually yielded faster results than expected. The water that went into the jar was 8ppm ammonia, 0 nitrates, 0 nitrites. Over night, it has gone to 6ppm ammo, ~.5ppm nitrite & ~10ppm nitrate.

Could the problem be with an unknown in the filter or another bacteria in the tank? Is there something that would, essentially, be feeding on the nitrogenous bacteria or preventing them from feeding on the ammonia?

 

[Hbbambislayer]

They may be unhappy but there gonna live they'll Thank you later. But 2ppm ammo is 1.75ppm to much for a fish in cycle Amy thing over. 25 is unacceptable your gonna have to keep changing your water out. If you wanna give your fish s break from the changing just do it tomorrow. Unless you have a lot of undisolved food and waste in the tank or a dead fish hiding somewhere nothing I would think is adding to your ammo source. Hopefully your ph will remain stable right now that's important but your gonna have to do more water changes 4 more 50% are probably gonna be needed maybe 3

 

[Hbbambislayer]

Also I read your stirring up the substrate during your water changes don't do that that can rapidly release toxins into the water just hover the vac or siphon over the very top get what you get and let it naturally break down. Remember not to over feed!