Ammonia spike???how?

[martinbinn]

So I've recently built a sump for my tank and its been running for about two months. I've seeded it with the sponge from my old filter sitting under the sumps input.
I've had no ammonia or water quality issues for about a month since my sumps installation.
now a little bit through my secend month I've gotten huge ammonia spikes at around .5ppm.
Overflow for my tank gets dumped into a compartment with some gravel to act as a pre filter, then into seachem matrix. after the matrix it runs through a sh*t tonn of very course sponge. then back into my tank.
could it be that my matrix has been fouled? but even if it has wouldnt the sponge have enough surface area to house the bacteria?
how quickly does bacteria die when it is no longer in water? because when i clean my sump its dry for about 20mins (or not dry, still really wet aha just not submerged or in flowing water)
my tank is fairly heavily stocked
thankyou guys

 

[David R]

To help answer your question it would be helpful to know;
-tank size/system volume
-pump size/flow/turn-over
-amount of media
-tank stock/feeding regime
-other water parameters (nitrite/nitrate, pH, temp etc)
-water change schedule

To me, it doesn't sound like a very good system if the only mechanical filtration you have before your matrix is gravel, and that may be the cause of your problem. You shouldn't really have to "clean your sump" if it is set up correctly, you should only be changing/cleaning the mechanical filter media every week or so.

 

[martinbinn]

okay thanks, so my matrix is probably fouled. how do i clean it up?
I'll add mechanical asap