What Causes Ammonia Spikes?

[sycko]

Hi
My tank has been cycled for about a month now with good readings of no ammonia, no nitrite, 10 nitrate and 7.4 ph!
but yesterday i did a waterchange to clear cloudy water(which worked a treat) but today when i did my test i had a ammonia spike of 1 with the same readings as b4 apart from ammonia! i treated the new water with Prime water conditioner and my average temperature is around 25-27c but i had noticed that i had turned the heater up to compensate for any cold water in the water change and 4got to turn it down so the temp was 30c!!! i have just started to feed my 25 fish in my 27 gallon tank with frozen blood worm instead of flakes but cant work out why i have this spike?

 

[Puffdaddy]

There are many factors that can cause an ammonia spike. How big is the tank and what kind of fish are in there? Did you do a fishless cycle then add all or most of the fish at once.

 

[sycko]

There are many factors that can cause an ammonia spike. How big is the tank and what kind of fish are in there? Did you do a fishless cycle then add all or most of the fish at once.

the tank is 127 litres its about 4 feet long and a foot and half wide and about 2 n half feet deep and the fish i have are
5 neon tetras
5 glowlight tetras
5 rummy nose tetras
2 peppered corys
3 plattys
2 rainbow neons
2 common plecs (soon to be re-homed to a bigger tank)
1 clownloach (soon to be re-homed to a bigger tank)

i didnt do a fishless cycle because i got bad advise from lfs to start off but the tank has had good readings for a month

 

[Puffdaddy]

Was the cloudy water milky in color? (whitish-gray) looks like smoke in the water.

 

[sycko]

Was the cloudy water milky in color? (whitish-gray) looks like smoke in the water.

Yes that sounds bout right

 

[Puffdaddy]

What I think happened was some how the bio-load in your tank increased which caused a bacterial bloom to compensate (consume the extra load) and since you did a water change which took out the extra bacteria causing the ammonia to spike, which otherwise would have been consumed by the bacteria. Chances are that your water will get cloudy again (bacterial bloom unsightly but harmless) to consume the extra bio-load. Once the bacteria colonises the cloudiness will go away on it's own.