HITH

[lipadj46]

Usually it occurs in aquariums with under-gravel filters, and sometimes in aquariums with canister filters, but rarely in aquariums with a BIO-Wheel filters.
Hope this helped.

Ha! magical bio wheels! Weird article and seems like someone is trying to marineland filters. No one is quite sure what causes HITH but the std treatment is metro with lots of clean water, up your maintenance routine.