Sudden Ammonia Spike? 18 Month Old Tank

[Jezz]

Hi all, bit of a problem i wanted to find the cause of, my 165L tank is about 18 months old, along with the filter i bought with it (fluval 205) 2 days ago i changed the filter foam pads and the carbon media, water stats were fine yesterday but this evening i noticed most of my fish at the surface breathing air, thought this seemed odd so checked water stats and ammonia was at 4.0ppm! Just done an 80% water change, will do another 1 in the morning and again in the afternoon, what could have caused this sudden spike? The filter media was not changed other than the carbon? Hope the fish will be ok

 

[Miss Dib Dabs]

How long had the carbon been in there? And the floss? If the answer is a long time then you effectively removed a portion of the bacteria from the filter. And deaths? A larger fish or a few small ones would cause that spike if left rotting in the tank.
P.

 

[Jezz]

How long had the carbon been in there? And the floss? If the answer is a long time then you effectively removed a portion of the bacteria from the filter. And deaths? A larger fish or a few small ones would cause that spike if left rotting in the tank.
P.

Ahh #41#### thought it would be ok changing the foam as its the original foam so over a year old, all the biomax media is still there though so hopefully wont take long to replenish the bacteria Not seen any fish dead etc, 1 thing though i took a small plant out when i did the water change, the plant looked fine but the roots smelled very bad? Perhaps this caused some of it too? Thanks for the reply

 

[Miss Dib Dabs]

Yup, that could have had an effect too. Substrate that goes undisturbed for a long period of time can go rather manky. Disturbing it would have released trapped chemicals. So all in all, a combo of items. Keep an eye on things, I'm sure all will settle down soon.
I cheated when changing my fish to their new tank. The substrate that had been under the rockwork had gone somewhat unpleasant (it had been a number of years) so I used new sand. The exposed areas get moved about constantly by the fish.

 

[Jezz]

Just tested water again this morning and ammonia hasnt gone down have just finished a 60% water change, will do another 1 this afternoon and same again tomorrow, really annoying!

 

[bitteraspects]

if the filter is full of bio-max, removing the foam should not have made a difference. did you wash the bio-max?

 

[Jezz]

if the filter is full of bio-max, removing the foam should not have made a difference. did you wash the bio-max?

Thats what i originally thought? Its got 2 baskets of biomax and 1 basket of carbon, i sort of rinsed the biomax in tank water, just moved the basket around a bit in the bucket of tank water to get some of the debris off? Know never to do it in tap water

 

[bitteraspects]

that answers my next question then. lol.
if you rinsed the bio-max in tank water, you likely did not kill the bacteria.

also, you should remove the carbon all together if you havent already. you dont need it, and it could be part of (if not the problem)

do you vacuum the gravel every time you do WC?
are you sure none of your fish have died or been sucked into the filter?
is the filter operating properly after you cleaned it?
how long was the filter off?

this is a pretty interesting situation. hope you get it sorted.

 

[Jezz]

that answers my next question then. lol.
if you rinsed the bio-max in tank water, you likely did not kill the bacteria.

also, you should remove the carbon all together if you havent already. you dont need it, and it could be part of (if not the problem)

do you vacuum the gravel every time you do WC?
are you sure none of your fish have died or been sucked into the filter?
is the filter operating properly after you cleaned it?
how long was the filter off?

this is a pretty interesting situation. hope you get it sorted.

Thanks for the help, didnt realise about the carbon thought it would help, any ideas what to use instead in the 3rd basket then or just leave it empty? Filter seems fine as far as i know, will know for sure once the water returns to normal i guess, but water flow etc is all as normal.
Filter was off for probably 30 minutes when i cleaned it? I have sand so cant vaccum it, but i quite often "disturb" most of it to release any chemicals.
No fish have died in the last few months

 

[bitteraspects]

you can either fill it with more bio-max (or whatever bio media you have available), or fill the middle chamber with another (finer) mechanical media for polishing the water, and move the bio-max to the top.

 

[Jezz]

Ammonia spiked back up to 4.0ppm again today About to do a big water change, any idea whats causing it to go up again? Filter cycling again?

 

[loraxchick]

what is your stocking? when you waterchange do you do a gravel vac at the same time? how do you repalce the water (does it disturb the substrate a lot when you refill the tank?). how deep is your substrate? gravel or sand?
by removing the carbon AND the sponges at the same time youve effectively removed quite a bit of media. the biomax has better surface area yes, but the sponges and carbon would have nice colonies as well. if you dont regularly clean the substrate undoubtedly there is all sorts of crud in there (which is why the plant smelled bad). any big disturbance, even from a big, cascading waterchange will kick this gunk up. coupled with the removal of the media.
sounds to me like "old tank syndrome" coupled with the removal of all the media.
*true carbon isnt "needed" unless removing meds and loses its effectiveness after about a week, but after that it is a nice surface for bacteria-just like any other filter media you would use.
best thing to do right now is to REALLY clean the substrate with a gravel vac everytime you do a waterchange...and keep doing those waterchanges until ammonia stops spiking like that.
do you regularly check your pH? had it crashed recently? (another symptom of OTS).
just a thought on the matter. hope you get it sorted
cheers

 

[Jezz]

Thanks for the reply I have sand in the tank, i do disturb it sometimes and no bubbles are released but still do it anyway. Sometimes when putting clean water in for a water change it disturbs a small layer in the corner of the tank's sand. Seems to have been a bad idea to change 2 sponges and the carbon at once, should have realised bacteria was on the sponge not just the ceramic noodles! So i may aswell leave everything in the filter now rather than remove the carbon? Havent checked the PH for a while will do a water test now and post results, have only checked ammonia tonight and its 4.0ppm

 

[Jezz]

Ok so water stats at the moment (before water change) Ammonia 4.0 Nitrate around 20ppm and PH is i think about 7.2 but not a close match to the colour card? So having a bit of a nightmare here! Hope they survive Havent had a spike like this for over a year! Shame on me for changing the sponges

 

[loraxchick]

is that pH reasonable to what youve had in the past? if yes then it was likely replacing the sponges. only waterchanges will help unless you can steal some mature media from somewhere and swap it with one of the new sponges (but dont take more than 1/3 of the mature media).
only other thing is to keep up with waterchanges and maybe increase aeration if possible. it shouldnt take too long for the colonies to replenish...just a pain in the meantime.
hope your fish handle it ok.
cheers