nitrate build up question..
 

Hi folks,
I've got a planted 125 chichlid tank, and the nitrates are always off scale.
It doesn't *seem* to bother anything, but I was wondering if this is normal
for planted tanks. Nitrites, ammonia, etc all measure 0, so the bio filter
is definitely cranking.....

I've done water changes (50% weekly), but it doesn't seem to make any
difference. I'm thinking this might be a result of the fertilizer spikes?

Anyway, is this something I Should be worried about? any idea what the
detrimental effects would be?

thanks
-JD