Ammonia problems

[m.ingram]

Hi everyone I have a 300ltr tank with 6 Goldfish in it and no matter what i do or how much water i change the ammonia keeps on going through the roof . This tank has been set up for 18 months now ,it use to be fine but about 2 months ago i started getting ammonia readings of 1 to 2 and they are only getting higher . I do and have always done 2x 40% water changes weekly on the tank . It is like the bio in the tank has crashed and not replenishing .Im using the some sort of rocks that are surpost to remove ammonia put thats not working either .
The fish are only getting fed every second day right now but that doesnt seem to be helping i was doing daily water changes but that only kept the ammonia levels at 1.
I know this isnt discus related but i have tried everything i can think of to try and fix this problem , so was hoping that someone here might be able to point me in a different direction 1

Regards Mark

[Nev]

Is there something evil or dead in the gravel maybe?

Maybe try moving a sponge filter from another tank if you have one, or borrow one from somewhere else like the LFS sure they'd help if you explained the prob.

Sorry not a great help, all l can think of.

Hope someone who knows more than me can help.

[Nev]

Just had a thought, have you checked your test kit? It maybe wrong, test some tap water result should be zero.

Also another dumb stray thought, try using a different de-chlorinator, yours may not be working and your water changes are killing the bacteria, won't kill the goldfish - they'll live in a sewer. And do only small changes for awhile.

[m.ingram]

Thanks for your input Nev
No dead things or anything funky in there i have pulled everything out of the tank and checked and clean all the rocks cleaned the gravel .
I didnt think about moving a sponge filter into the tank i have got 2 already going in my pepp grow out tank i will move one over .Thanks for that .With the test kits i have one from API and a seachem one and they are both reading the same .
Thanks again

[Ghoti]

Still worth testing your water source. If it contains ammonia no amount of water changes will change it.

Cheers,
Scott

[m.ingram]

Hey Scott that was one of the first things i did . It did it straight out of the tap and after it had been ageing for 24hrs 0 ammonia .

[boxters]

do you have any wood in the tank. Tanins give a false positive ammonia reading

[m.ingram]

Hey Marlon no wood just a couple of large rocks .

[boxters]

i had the same problem with a system once before. Have you used any meds in their. Some meds turn the essential bacteria toxic, in which case boiling the media should fix the problem. It may also be that your water circulation is to fast and not giving the water enough contact time with the media or the fish may have grown so their is a need for more media, or your test kits could be out of date. What are the other readings i.e. nh2 nh3 kh and gh

[m.ingram]

Hey Marlon it makes sense now i used some acrifavine a about 6 to 8 weeks ago in the tank . I had the filter disconnected and running into a bucket . But maybe i didnt get rid of all the acriflavine out of the tank before i hooked the filter back up .I will try boiling the filter media .
thanks for the advice .

[m.ingram]

I Just wanted to say thanks to Marlon for his advice . Boiling the media worked a treat .The tank is now back to normal no ammonia and my fish are happy again .