1. Unexpected loss of beads from a PBF filter may result from:
A. When initially starting up a PBF unit, it is common to have a small number of small, undersized beads pass through the bead retention screen and into the culture tank. While we us virgin plastic bead media in all of our filters, we cannot totally eliminate undersized beads.
B. The bottom screen on most PBF filters is not screened. Failure to install a siphon break as part of the external plumbing assembly can result in the loss of beads from the filter through the drain line due to a siphon. If the siphon break is installed properly, the water level in the filter cannot drop below the inlet fitting on the side of the filter, thus preventing the beads from being drained from the filter.
C. Over washing the beads or extended operation of the mixing motor can result in bead loss. If the mixer is run for an extended period of time, bead are forced to the bottom of the filter and become captured in the diffuser. If you suspect this is occurring or have reason to run the mixer for an extended period of time, you can eliminate the bead loss by turning on the recirculation pump for 5 seconds to force any trapped beads from the diffuser.
2. The mixing motor should never be run unless the filter is full of water and the circulation pump is turned off.
Running the mixing motor even for very short periods of time without water will result in overheating of the bushing in the shaft support pipe. If this occurs you must replace the bushing.
3. If sludge drains from the filter rapidly then slows to a trickle it is generally due to lack of an air break on the top of the filter.
This typically occurs when the effluent line is submerged in the culture tank and there is no way for air to enter the filter as the sludge is drained from the filter. Installing a check or manual valve in a TEE on the effluent line easily solves this problem.
4. If you experience cloudy water, you may have a small air leak on the suction side of your pump or an air stone may have migrated to the vicinity of your pump intake.
Bubbles accumulating under the bead bed eventually channel upwards releasing solids. If you suspect this may be causing a problem in your system you can tighten all threaded fitting on the intake side of your pump, wipe silicon sealant on all pipe joints and/or move the air stone(s) away from the pump intake.
5. Never open the unscreened emergency bottom drain unless your pump is turned off and your filter is full of water.
This valve is not intended to use during normal backwashing of the filter, it is only to be used periodically to check and see if sludge is accumulating in the bottom of the filter or to completely drain the water from the filter. If this valve is inadvertently left open, you can, and will, drain all the beads from your filter.
6. If when you turn on the mixing motor for the first time, And the beads do not mix- check the direction of motor rotation.
The motor should be spinning clockwise. (From right to left). If it is not, the motor has been installed incorrectly on site. Rewire your motor correctly and the shaft should spin clockwise.