Depends on the tank, the filter, and the amount of Purigen you're using. That's certainly on the short end. I usually check mine after a few months, not weeks. Are there a lot of organic materials in the tank?
It turned brown, thought maybe it was a stress coat I used, but had no problem regenerating it. This is on a 72 bow with an eheim 2217 a marineland hob and a sponge filter, no plants and 20 fish.
Sent from my C5215 using MonsterAquariaNetwork App
That's incredibly fast. I use 750 gallons worth in my 125 and it stays relatively light for atleast 4-6 weeks and doesn't turn brown for 10-12 weeks atleast. I also have an enormous bio load so I'm not sure why yours would go so quick. Just because it turns brownish doesn't necessarily mean its exhausted I've read it can turn black before its totally useless. Seachem has a great site with question forum it may be worth searching or asking on there.
Sent from my SCH-S960L using MonsterAquariaNetwork App
Yeah, I'm going to check out the Seachem site, I haven't used the api stress coat in awhile, but that is one listed as causing it to turn brown and not exhaust.
Sent from my C5215 using MonsterAquariaNetwork App