Nitrite Spike... Worried!

bmonki

Fish Crazy
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Well i just did my normal water test (usually done daily but yesterday was missed) -
amm - 0
N-Ite - 2ppm!!!!!

#136###! what could have caused that to happen? we've had 0 amm, 0 nitrites for months now! No chlorine has gone into the filter media as i always take it out of the tank while doing a wc (it gets put into old tank water so it doesnt dry out)

i added some nerite snails on weds, but no other additions to the tank recently.

i took the fake plants out and gave them a good scrub a week ago tomorrow as they were covered in algae but the substrate wasnt removed and the filter was only wiggled around in dechlorinated water.

im just waiting for the heater to cool down before doing a water change, planning on a 90% ish to try and rectify the nitrite readings but i would really like to know WHY this has happened in a now stable running cycled tank so i can stop it happening again :/

temp is around 77 F
 
I would do a "head count", especially of the new Nerite Snails. I had a poor adult Rabbit Snail die out of view and the ammonia/nitrite spike was incredible considering the size of the body inside the shell.
 
Why do you take the filter out when doing a water change? You should just switch it off, do the water change adding dechlorinated temperature matched water while the fish are in and then switch the filter back on. If you put the filter in tank water it shouldn't make such a change anyhow, it's just not needed(or do you mean the filter media only) Maybe while scrubbing excessively the tank, washing the filter media and if you also siphoned the gravel you may have removed enough bacteria to cause a spike. You should do 1/3rd of the tank at a time and don't scrub the tank and wash the filter at the same time.

In the meantime, after doing the water change, and if you don't have salt sensitive fish(scaless fish) like corys, loaches, etc...(research), you can add 1tbsp of salt for 5 gallons of water(dissolve it first). It will neutralize most of the nitrite so it is not toxic to the fish while the tank is recovering.
 
I would do a "head count", especially of the new Nerite Snails. I had a poor adult Rabbit Snail die out of view and the ammonia/nitrite spike was incredible considering the size of the body inside the shell.

all the snails are fine :/ (although one did try to escape out of the siphon while doing the water change)
 
Why do you take the filter out when doing a water change? You should just switch it off, do the water change adding dechlorinated temperature matched water while the fish are in and then switch the filter back on. If you put the filter in tank water it shouldn't make such a change anyhow, it's just not needed(or do you mean the filter media only) Maybe while scrubbing excessively the tank, washing the filter media and if you also siphoned the gravel you may have removed enough bacteria to cause a spike. You should do 1/3rd of the tank at a time and don't scrub the tank and wash the filter at the same time.

In the meantime, after doing the water change, and if you don't have salt sensitive fish(scaless fish) like corys, loaches, etc...(research), you can add 1tbsp of salt for 5 gallons of water(dissolve it first). It will neutralize most of the nitrite so it is not toxic to the fish while the tank is recovering.

i out take the cartridge containing the media (sponges and biomax noodles) as we're pretty heavily stocked and every weekly water change i rinse it slightly as it collects a lot of debris/poo. hopefully i wont need to do that much longer as im saving for a bigger filter (ours states 500lph but aparently thats not enough for a 170l ish?) also depending on how much water i change sometimes its easier to fill back up with tap water then dose whole aquarium with dechlor so i take the filter out as habit

i have corys and plecos so i dont think i can use salt - but i've put some extra prime in to try to detox it.

i only washed the plants and vacced the gravel (plus rinsed off excess from filter) last time but it did look a lot lot cleaner when i was done so maybe i had overdone it... i just hope it doesnt take too long to rectify!
 
Yeah, this filter is way below the tank requirements, for a tank this size and if it's heavily stocked, get a nice external 1500L/H. Even with washing the media of this 500L/H filter is just waiting for a disaster to happen which seems to be the problem. When the filter in a tank is small for the tank, in order to cope with the bioload of the tank bacteria will settle everywhere else where it finds it livable. The good clean you gave your tank actually has the opposite effect of good maintaining.
If you can't afford a bigger filter in the mean time, instead of washing the filter media everyweek which removes part of the bacteria no matter what, just don't overfeed and siphon the gravel from every excessive ammount of debris and food instead, so the filter doesn't get clogged and can handle the biological filtering, rather than mechanical filtering of poop and food.
 
does it have to be an external? or are there internals that would be good enough? not sure we have space for external :/
 
does it have to be an external? or are there internals that would be good enough? not sure we have space for external :/

I can't recall an internal filter that can filter over 1000L/H. The best way is to put two internal filters in this case, adding an extra one and keeping the old one, if you don't mind taking space from inside the tank. I have the Fluval U4 which is a very good filter and is rated 1000L/H. It costs 50 euro in the zooplus online shop.
 
does it have to be an external? or are there internals that would be good enough? not sure we have space for external :/

I can't recall an internal filter that can filter over 1000L/H. The best way is to put two internal filters in this case, adding an extra one and keeping the old one, if you don't mind taking space from inside the tank. I have the Fluval U4 which is a very good filter and is rated 1000L/H. It costs 50 euro in the zooplus online shop.

would one u4 not be enough then?
 
Hi bmonki

I would say not. If you say you are heavily stocked, you really need a filter that can filter more than a 1000l/h otherwise you may encounter the same problem.

Is there no where to hide the external filter below the tank on a cupboard or behind it somewhere? I really would recommend an external, you won't regret it!
 
if i put some of the toy boxes in the loft i could poss squezze it underneath... if it werent too large or tall... how does it pick up the water and put it back in? would i have to make holes in the tank? any reccommendations of cheap but good filters then? budget is stretched as is :(
 
I have a tetra Tek ex600 in the cupboard below my tank. It's basically a canister with an in and out pipe that hook over the back of my tank. If you you tube it you will see the basic set up and how it works.

Perhaps see what second hand ones you can get, or as mentioned, get a second internal in addition to your current.

Are you able to re home some of the fish so you are not so over crowded and stretching your filter?
 
Really would rather avoid re homing any fish, it's a nice balance in there, it's just the plecs pooing too much I think. The only fish I'd want to re hone us the remaining albino Cory as he is lonely now.

Aren't external filters noisy though? I like the silent internal we have
 
My external is quieter than the U3 internal I had......its very nearly silent!

I am realy pleased with it and its the best thing I have bought too. The water is much clearer for it to as its filtration is just far superior to what I had.

Have you had a look in the classifieds section to see whats about?
 

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