Want to add bio filtration to my CombiBio 50 system
My cute little tosai are becoming monsters so I want to add more biological filtration.
I have a ProfiDrum CombiBio 50 in a pump-fed, above water level setup. It gravity feeds back to the pond, so to keep the water level in the bio chamber, Norm had Jan at ProfiDrum fabricate a collection box with standpipes. It works well. Before I bought the CBB50 I had metered the pond fill at 13,000 gallons, so the filter was sized just right. After finding that baking soda additions didn't change the KH numbers as expected, I decided to do a salt test. It turns out that my pond is actually 16,500 gallons.
What is my best way to add more bio, given these limiting factors:
- available space is 44" width and 30" depth if I get rid of 16" collection box
- useful height is determined by the water level in the collection box (or water level in the bio section of the CBB)
- must be gravity fed because adding an outlet pump would be complicated to operate
- must outlet on the front (toward the pond) because there is a gate to the right
Should I just add another MBBR with K1? Or should I have Zac Penn fabricate a custom zakki shower to try to get some denitrification? Because the CBB has bottom outlets, I have to figure out how to maintain water level in the MBBR section of the CBB as part of whatever I add. Any suggestions will be appreciated.
Here's a picture of what I have now:
Wow, I like the custom standpipe. I am a bit confused about what it actually does in a pump fed setup. Is is required to make sure you get enough gravity flow back to the pond?
My combi 30 came with 50L of M1 but it can handle 100L. Did you already max out your M1 capacity or can your unit handle more? If it can handle more I would start with adding more M1. As far as adding additional filtration it really depends on you. Obviously you are enough of an advanced ponder to probably know the options and it really is a matter the usual (budget, real estate available, maintenance, etc.). Keep us posted since you definitely can provide good information for those considering a pump fed RDF system.
I'm running 250L of K1 in my CBB50. The collector box is necessary to keep water in the MBBR. Because the outlets of the CBB are at the bottom, without a collector box it would always be empty. Remember the filter is above pond level.
Got it. Thanks for the diagram. Makes perfect sense. I suspect the bottom outlets (on the MBB chamber) could have been easily capped off and new outlets put at the appropriate height on the MBB chamber. Perhaps there might be an issue with the K1 overflowing into the pond so that is why they put in the extra chamber???
It seems like you may be able to add some screens to the top of your standpipes and put in a diffuser in the standpipe box for additional MBB if you decide to do that.
Last edited by Douwe; 03-01-2017 at 02:07 PM.
Zac is currently working on a shower filter designed to follow the profidrum. I believe it for a gravity fed setup so I am not sure if it would work with a pump fed but it might be worth asking.
The outlets are at the bottom because the screen that retains the K1 is suspended above the bottom of the chamber. This is a good system because it gives a huge surface area to screen the media so that it doesn't bunch up like it would if I just put screens over the outlet holes, or over the standpipes. I've thought about adding media and an aerator to the collection box (or a larger version of the box I have) but I worry about screening the media close to the outlets because they would be held by suction where the flow is concentrated.
Originally Posted by Douwe
Maybe I just need to make a second bio chamber to insert between the CBB and the collection box. I would end up with the approximate equivalent of a ProfiDrum 65/40 and a BioFilter 50.
The pump-fed, above water level installation does add some complications to equipment that is primarily designed for gravity feed. This was what I was hoping to find, although I was also considering trying some submerged Cermedia, but I don't know if it would provide the denitrification that showers are rumored to provide. Looks like I need to call Zac.
Originally Posted by tbullard
Last edited by Marlo; 03-02-2017 at 11:55 AM.
Yup, I hear you and clogging of inlets/outlets would be problematic. In terms of screens over inlets/outlets I was thinking more along the lines of extensions, internal to the MBB (a foot, or so, of perforated pipe covered with course mesh), that would roughly provide a similar surface area as the mesh below. In your setup it looks like you have lots of room to add a system since you are not confined to space inside a pit. I kind of like the idea of a an add on shower, if you can do it, since my understanding is that showers are very good at nitrate "removal".
Originally Posted by Marlo
Profi sells just MBB's and showers so if you wanted to keep the same look you might be able to add those to your existing:
BTW I could not help but notice that it looks like your Profi is out in sunlight without protection. I am wondering if there are any concerns about sunlight UV having a negative impact on the plastic?
Yes, polypropylene is unstable in UV, although I was told by someone that the type they use is stabilized. I can't find my reference on that, though. At any rate, I'm planning to build a cover over it.
Originally Posted by Douwe
That would be wise. As a mechanical engineer, that has designed many plastic parts, I am not convinced that stabilizers are long term effective.
Originally Posted by Marlo