Empty Cycled Tank Still Running....

[marcybeth0281]

When we transferred our fish to the 46gallon tank, we left our 10 gallon tank up and running with the gravel, plastic plants, water, the whole nine yards. The only thing that changed was that there wasn't fish in the tank.

We've been keeping up with water changes every 2 weeks because we eventually want to get a pair of dwarf puffers - but we just haven't had the time or the money to deal with it right now. We just don't want to lose all the beneficial bacteria we've built up in the year the tank was running.

All of a sudden it occurred to me that maybe I should be doing something to promote the biological filtration since there are no fishies in the tank. I may have screwed it up beyond repair - it's been empty for about 2 months now.

Just tested the water: NH3 is at 0 (obviously - no fishies!), NO2 is at 0, NO3 is at 10ppm, and pH is at 6.0. If we need to put fish in as a holding tank or if we get new puffers, is the tank going to need to re-cycle or anything? Have I screwed something up? I'm still a semi-newb when it comes to this type of thing. Help!

 

[m00se]

2 months? I believe, without a food source of ammonia, your filter bacs will die off at the rate of about 10% every 24h, assuming your water is oxygenated. Unfortunately, with no fish in your tank for two months, you're likely to have lost your colony. What you need to do is dose the tank with ammonia and check your water stats at 24 hours. I'd guess, though, that your tank will be near fully un-cycled by now, unfortunately.

 

[deathy]

yeah m00se is right, you will need to restart the cycle process again, if you got some media from the other tank you may be able to boost it quicker, but you need to give the tank some ammonia.

Hope this helps

 

[marcybeth0281]

okay - so i should dose the tank with a few drops of ammonia every day to keep the cycle going just like i was starting over? filter has been running with media since the fishies left.

if the tank has lost all the bacteria, why is my NO3 testing at 10ppm?

the science of the thing really gets to me. i understand how to test water parameters and what is unsafe and take direction on how to cure problems - but the actual science baffles me, even in the easiest of tutorials. so forgive me if i sound naive. i'm a right brain thinker.

 

[marcybeth0281]

also, i have a 5g hospital tank up and running with no fish currently (thankfully). it has mature media and the heater from an established tank to promote biological filtration.

my platy is about to give birth and i'm going to transfer her there soon. should i be dosing that tank with ammonia, too? it tests the same as the 10g with the NO3 being a little lower at 5ppm. how do people deal with un-cycled hospital tanks when they don't leave them up and running all the time?

 

[Rediahs]

NO3 is at 10ppm just because it could have come in in the tap water, could be leftover from when you had fish, could be random matter decaying... it has no bearing on whether your tank is cycled or not.

2 months without food is a long time!! I think the bacteria are dead... sorry.

You have a different tank? You could seed it with mature media.

The way I learned to do a hospital tank is not to keep it up and running all the time, but just to keep some filter media ready in your tank to switch into the hospital tank anytime. If 100% of the media you put into the hospital tank is mature media it will probably be instant cycled.

 

[marcybeth0281]

OK, so when the fry come, I can just cut some of the sponge off from the current sponge in my 46gallon to put in the filter in the smaller hospital tank. Should I add some carbon and ammo stones? I usually don't have that type of media in the hospital tank, but since I'm going to be using them for the fry...I'm not sure if that would be beneficial.

In regards to the 10gallon, I dosed it with 30 drops of ammonia this morning and will take a reading tomorrow morning and then ask for further advice.

 

[marcybeth0281]

OK - I dosed the tank with 5ppm of ammonia yesterday (i did 2ml, which is the equivalent for 5ppm in a 10g according to the calculator) and just tested it at 24h.

NH3: 1ppm
NO2: 0ppm

I suppose I should just continue to dose the tank with ammonia like with a fishless cycling and wait for my nitrites to start showing up? It sucks assuming all my bacteria is gone, but I don't really know what else to do.

Advice???