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Airwashing Bubble Bead Filters
Air-Powered Washing of Bubble-Bead Filters – by Michael J. Ready, Santa Cruz CA
Cleaning a Bubble Bead with Air
Bubble Beads sometimes get clogged and there is very limited access to the beads. This information is MOSTLY applicable to the Bubble Bead filtration system, which are easily recognized by their vertical “dumb-bell” shape.
Air-Powered Washing of Bubble-Bead Filters
Michael J. Ready, Santa Cruz CA
We know you’re a believer in bubble bead filters (BBF) technology so we thought that I’d send you another idea for washing the beads. I’ve been intuiting that the simple draining technique provided by the BBFs was not breaking up the beads sufficiently and that there may have been some “channeling” going on within the filter. (We determined this by putting an ear to the BBF as it drained. When the beads are thoroughly broken up, the sound is more like static. If the beads are sticking together, it sounds more like rocks and less like static. Clumping beads reduce the surface area available for bacteria, i.e. channeling, and providing pockets for anaerobic conditions within the bead clumps.)
We implemented your power washing technique but have found that it takes quite a bit of water (100-200 gallons for our BBF-5) to thoroughly break-up and clean the beads. We live in Santa Cruz CA and conscious of water usage so we thought there had to be a less water wasting way to clean the filter.
We came up with another technique that does not take as much water as your power washing technique (and have recently seen it in implemented on other fluidized bead filters on the recent Santa Clara CA pond tour). We retro-fitted a 1 HP air blower (that we took off our hot tub because we never used the air-only mode) to blow air into the air port on the BBF as shown in the figure below. Air blowers like this are available from pool and hot tub equipment stores.
Here are some thoughts behind the design:
We “T”ed the blower into the original air check valve so that when we drain the filter, the air comes in through the original check valve. We put another check valve between the “T” and the blower for 2 reasons: 1)to keep moisture out of the blower and 2) keep standing water out of the hose that would probably go anaerobic between cleanings.
The blower should be above the highest point of the BBF in case water ever gets into the hose and thus exposing the electrical motor and power to water. (An alternative design could mount the blower lower but loop the hose higher than the top of the filter to prevent any danger of water getting into the blower.
The blower MUST BE wired into a GFI outlet to prevent potential electrical shock!!
We used a piece of 6’ piece of 3/4″ hose to make the routing easier than with PVC. A larger hose would provide more air volume but the 3/4″ seems to provide satisfactory operation. Using MPT-to-(male) hose adapters made it easy to connect to the two female hose fittings. Female hose fittings prevent the hose from twisting when connecting as would occur if male hose fittings were used.
We put a PVC valve on the air port because we’ve found that check valves can drip a little. Since we have the BBF on a wooden platform out of sight in the garage, we didn’t want any water leaks.
Here’s how it works:
- Power off the pump.
- Open the PVC air valve.
- Open the drain port for about 5 seconds to let some air in, then close it.
- Turn on the blower. If you put your ear to the BBF, you’ll hear the beads breaking up. I’ve found that the beads break up in about 1-2 minutes.
- Turn off the blower and drain as you normally would. (I suppose you could leave the blower on though I haven’t tried it.)
- You could power wash with water it to really get all the flotsam out but we haven’t found this to be that big an issue. Some flotsam washes back into the pond but is recaptured by the BBF within an hour or so.
Our experience has been very good. The beads really get broken up and cleaned. We don’t know how it affects the bacteria population but we don’t see ammonia spikes after cleaning. (We use a BBF-5 on 3000 gallons, a little over designed but we wanted substantial design margin.) With both your original power wash idea and the air blower, we can keep the beads clean and really broken up without substantial water losses. In the summer time, we wash the filter 2x per week.