Ammonia Problems

hi, i have had lots of problems lately with dying fish etc , i have lost 3/4 of my stock,.  but last 3 weeks my remaining fish have battled on. now i have a very high ammonia reading and have done 2 x 30 % water changes, stopped feeding them and still the ammonia levels are very high though my fish don't seem to be bothered by it..  i clean gravel weekly and test weekly with 10% water change..  any one any ideas..  thanks   60l tank with 3 zebra danios and 3 cardinals and a rummy nose tetra..  ph is 6.2 ,nitrate 5ish  and nitrite 0 .. 

The good news is that with your pH you can have a high ammonia level without harming the fish. Ammonia exists in two forms in our tanks, toxic ammonia and less toxic ammonium. The amount in each form depends on both temperature and pH. The lower the pH, the more that is in the less toxic form. Our test kits can't distinguish between the two. The reading is for both added together. With your pH, assuming the temp is around 25 deg C, your ammonia proportion is well below the danger mark even with a test reading of 4ppm.

However, it is still good practice to lower it. It will have to go somewhere, and that is usually into nitrite - and nitrite is more toxic at low pH so you do need to keep an eye on that.

It sounds as though something has happened to your ammonia eating bacteria, and possibly your nitrite eaters too though you won't be able to tell until the ammonia eaters make some nitrite.
Have you done anything to the filter - changed the media, the filter itself, washed the media in tap water - forgotten to add dechlorinator at a water change?
Has anything been sprayed in the same room as the tank?
Have you accounted for all the fish? A dead fish stuck somewhere in the tank will make a lot of ammonia.


In the meantime, I'm afraid a lot of water changes are needed. I know the toxic part of the total ammonia is very low in your pH but it will end up as nitrite which will be very toxic in your water. You need to keep a close eye on your nitrite level and do big water changes to keep that low if it does show up.

For ammonia, use this calculator. Leave the first box set at NH(NH3 + NH4); enter your ammonia reading; set salinity to zero; enter your pH and temperature. Then click calculate. You want the number in the second box on the right hand side, NH3 concentration. If that number is below 0.02, the fish are safe and you don't need to do a water change.

But with your pH, any reading above 0.25 nitrite will be toxic. It is possible to use plain salt to mitigate the effect of nitrite but I'm not sure how your cardinals would cope with salt. If you do get nitrite and want to risk salt, let me know and I'll give you the calculation for the amount to use.

hi, did a big water change and ammonia still high so i tested the tap water… it read .25 to .5, this isn't normal is it? is there anything i could do, i.e. use bottled water, i would like to get the ammonia down even though it doesn't seem to affect my fish
 , thanks

The API ammonia test is notorious for giving false positive results under fluorescent and energy saving bubs.

On this subject - despite having had a tank for a while now I've never been sure whether you should hold the test tubes against the white area on the colour charts are hold them away from the charts? I've found that the readings can appear quite different depending on which approach you use, Nitrate in particular being the most problematic - what can appear orange held up to a window, then appears red when held against the white area of the chart!

Well that's good news at least as that's what I've been doing - would've been somewhat awkward to find out I'd been doing it wrong for the last year!! 

hi, yes i hold against the chart too…  i had 21 fish in  about july with no ammonia or nitrite and everything rosy, now down to 7 fish and big ammonia,( cause unknown why they all started to die ) ill just keep trying to get it down.. also the manufacturer of the tank say to replace the filter and carbon filter every month is this right ?  i change carbon one but not the filter ( they call it a floss algaway media) they also say not to clean the bio holster … i know that if i did that i would lose all my bacteria so obviously i don't  clean it…   so what I'm saying is do i replace both as they say monthly… ( its a panorama media cartridge 64l)  thanks

hi, a bio holder is the case the filter media sits in i guess, they prob think it sounds better. so 2 sponge filter media it is then..by the way the algie pad thing is green and made of a fibre type material not like a sponge i guess more like a scouring pad ;-)  i will try new sponge media this weekend and put some tetra bacteria stuff in too.  how long do you think before i see results in ammonia eating bacteria and nitrite , thanks
 ps it is from pets at home and a love fish brand

ok, ill check before use, thanks sue   

hi, i have been changing water at about 25% every other day and also replaced carbon filter with another sponge , on my readings i was getting high ammonia, high nitrite and low nitrate reading and ph 6.4, so i know my bacteria was working then two days later ph 6.0 high ammonia and no nitrite and low nitrate, should nitrite drop so fast without nitrate going up..  just cannot get ammonia down ……  maybe its my filter, could you suggest a filter that would be good for a 60 litre tropical fish tank as this i the route i might go down , thanks