Simply, a Herbie is nothing more than two standpipes in a overflow chamber, one higher (secondary or emergency) than the other and the lower one (primary) having a valve on the drain line just above the sump.
The valve is closed until the water flowing into the primary is over the top of the standpipe and not drawing air. The secondary is higher than this water level and is normally dry. Purpose of the secondary is since the primary is already restricted and backing up water, if the was to become more blocked it would overflow the tank, the secondary prevents this. Often the primary drain output is a little below the water level in the sump, the secondary just above. If you start hearing water splashing from the secondary, it indicates the primary needs to adjusted or has gotten a blockage. Combined with a ATO they are set and forget though.
The huge
RC Herbie thread
Also check out Reefjunkie non-traditional Herbie layout
here
11-06-2008, 01:02 AM
Threaded Mode
