cycling trouble

[tjnelson44]

I have been having trouble with the nitrogen cycle in my breeding tanks. They will be fully cycled for a while and then they seem to uncycle. I will just get an ammonia spike and it will not go down. The production of nitrate just halts. In others that I have tried to cycle, the ammonia was being converted to nitrite and then the process would stop. I have not added any more fish and the feedings have stayed the same. I use RO water with some Kent RO right to bring the tds up to 70 ppm. The pH is 6.8 and temp is beween 75 and 80 F depending on the tank. These are bare bottom tanks with a sponge filter in each. This is driving me nuts. I have never had problems with cycling tanks before this and I can't figure out what I am doing wrong.
Trevor

 

[aspen]

your nitrogenous bacteria are being killed off somehow, that is obvious, right? i would think that it is most likely from chloramine in your tapwater. fully test your tapwater for chlorine, free (regular chlorine) and bound (chloramine). as you know, until you get that under control, your fish will be dying from the stress. i bought a chlorine test kit which i use from time to time when my water seems to be stressing out my fish.

rick

 

[tjnelson44]

Thanks for the response, I did consider the possibility of chloramine in the water supply so I called the water company. The guy that I talked to assured me that they only use chlorine gas and raise the level to 3-4 mg/liter. But I would like to test it for my self since I am not sure if I trust them. I did try something that I read some were but i am not sure how accurate or correct the test may be. I tested my tap water for ammonia and there was none. I then added some chloramine remover to my tap water and tested again. A little amnonia was present this time. I just don't know if the chloramine remover falsified the test. The idea behind this was that if there was choramine, it would release ammonia when broken down. Also, would the carbon filter on my RO unit take out the chloramines? Were did you get chlorine test kit?

 

[depthc]

I suppose the bacteria must be dieing off like aspen mentioned. Ive never dealt with this personally so im unsure what could cause this.

My advice is just keep up on your water changes so ammonia,nitirite and nitrate cant accumulate.

Its also possible that your bacteria colony is adjusting to an increased bioload somehow, but as youve said your feedings have not increased nor has your fish load. So im unsure of what the real cause is.

Water changes will do though, good luck.

.dc

 

[fishgeek]

are larger molecules like chloramine going to get through your r/o filter ?

isnt carbon in the prefilter there to remove heavy metals/toxins
when you say you tested your tap , does that mean you are using some water from the tap or you tested your r/o water

my first thoughts are in line with others has to be some breakdown in biological activty of your filters

is the flow over the sponge slowing down as they silt up?
how do you clean the sponge's
anything else that could be getting into your tank and damaging biofiltration
anything else that could be getting in as source of ammonia

more questions than answers sorry

 

[fishgeek]

denitrifying bacteria instead of correct species?
lack of oxygen for you bacteria on the sponge?


again just more questions

 

[tjnelson44]

I clean the sponges about every two weeks by submerging them in the water I remove form the tank and giving them a squeeze. I tested the tap water not the RO water. The reason that I asked if chloramine could make it through the prefilter is that I have seen special prefilters that are supposed to remove chloramine. This made me wonder if a regular one really did the job.

As for the mention of correct species, do you think it would be possible to have a strain of bacteria that is overly sensitive. I do know that many species of bacteria have lots of different strains with some having unique properties. If this is the case then I may try to seed it with some bacteria from a friends tank

I would not know how to tell if the bacteria are not getting enough O2 on the sponge. The fish in these tanks are not gasping at the surface.

I can't think of anything that would damage the bacteria colony unless they are very sensitive and my water parmeters may not match exactly when I do water changes. Maybe that is it.

I don't think there are any other sources of ammonia entering my tank.

Do you think it may have something to do with the RO right? These problems started about the time that I started mixing RO right with my RO water instead of mixing tap water back in. Is it possible that there is some essential nutrient that is not supplied in enough quantities to sustain a bacteria colony long term? Maybe that would explain why it seems that the bacteria is just "running out of gas."

Thanks for the help. It is very much appreciated.
Trevor

 

[aspen]

>>'I tested my tap water for ammonia and there was none. I then added some chloramine remover to my tap water and tested again. A little amnonia was present this time.'

i believe that this is proof that chloramine does indeed exist in your water. ie the ammonia isn't detectable till it is broken out of the chlorine/ammonia bond. try adding some prime to your reservoir before you do changes. i'm sure that wil fix you up. the reason i'd be using prime is, that once the chloramine has been neutralised, the ammonia is still toxic to fish. you don't want to use that water for fry tanks, it will likely result in a rise in fry mortality while your adults could probably handle it, till it has cycled through your filtration.

after using prime specifically, the ammonia is not toxic yet testable. but prime will lock up nitrite and ammonia, yet these are still available to the nitrogen cycle apparently but not in a form that is toxic to fish.

as for a regular carbon filter, carbon will not remove chloramine.

let us know how it goes, please.

rick

 

[dhm325]

How often do you test your pH? If you use RO water, the PH will be prone to crash even at 70 ppm. As the pH falls the amonia that the baceria culture "eats" changes to a form that cannot be digested by the bacteria. Eventually the culture starves. There was an earlier discussion of this problem on this forum. You might want to search for it. My breeding tanks were prone to this problem because when fry reach the free swimming stage there is a tendency for the pH to fall because of the acid added to the water from decomposing brine shrimp (or whatever else you feed your fish). Best of luck.

 

[tjnelson44]

I do not test my pH very often but when I do test it is never lower than 6.5. The waste never gets a chance to accumulate. I do lots of water changes. I think I may try several things since I have some empty tanks right now. I will pick up some giant danios and see if I can find something that works now that I have some good suggestions. I am really leaning towards the chloramine thing but would like to try some other possibilities too. I'll let you all know when I figure something out.
Thanks,
Trevor

 

[fishgeek]

dont acyually know aspen's prime product
though would suggest that the pH of the tank is more likly to allter the state of the NH3 low ph tends to favour the non toxic unionised state of ammnia

so if your tanks have high pH you may find primes claim untru, or if you hvae low pH you may not need primes added benefits

 

[dhm325]

...pH of the tank is more likly to allter the state of the NH3 low ph tends to favour the non toxic unionised state of ammnia...

I think that the change to the "non toxic unionised state of ammonia" is what causes the problem when the pH falls. This form of ammonia cannot be 'eaten' by the bacteria culture-- so it starves. Then when the pH goes up again -- say after a water change --. The ammonia reverts to the toxic form and there is no bacteria culture (or the culture is too small) to deal with it.

 

[fishgeek]

i don't know and i dont believe that filter bacteria cant cope at low pH
i have tanks that have low pH 5-5.5 and filters seem to work

bacteria are pretty hardy , though as i stated first i dont know for sure

 

[aspen]

>>'to the "non toxic unionised state of ammonia" is what causes the problem when the pH falls. This form of ammonia cannot be 'eaten' by the bacteria culture-- so it starves. Then when the pH goes up again -- say after a water change --. The ammonia reverts to the toxic form '

that is 2 different things we're talking about here. seachem prime will bond to ammonia and also to nitrite to avoid killing your fish from these toxic forms of nitrogen. that is why it is such a good product as compared to regular water conditioner. what you're talking about is the conversion of ammonia to ammonium realating to changing ph. that is something completely different. here's seachem's blurb about their product:

http://www.seachem.com/products/product_pages/Prime.html

i don't use water conditioner, i simply age my water. but i have some on hand jic.

rick

 

[tjnelson44]

My tanks are back to normal. It seems that there may have been a little something extra in the water supply for a while but now its gone and every thing is good. I tested the water after treating it with chloramine remover and this time there was no ammonia present. Thanks for the help.