Bob Fenner question
Hello,
*Re*: Bob Fenner's "Up-Flow" Pond Filter 12/24/08
<Okay>
Just a quick question for Bob regarding the *Aeration Tower* on the Up-Flow Filter. It appears that the Aeration Tower or PVC pipe used for this is completely OPEN at the top (other than the Intake line from the pump).
<Yes it is>
Is there any concern for debris like leaves, bugs, etc. entering thru this open ended pipe or is the gap too small for this?
<Not really an issue... that is to state, over the years of making MANY of these units we never had troubles associated with the "stand pipe" being open at the top>
Ideally, how big of a gap should one shoot for..............for example, use a 3 inch Tower with a 1 1/2 inch intake? Would this be too big of a gap or could one use some screening around the Intake line?
<You could use screening of some sort... all-plastic (various kinds are sold by Home Depot, Lowe's and the like), the tower... Diameter? I'd make four inches (stock for schedule 200...) in diameter... above the rest of the filter unit? I'd make at least six inches taller... the intake as in the return from the filter "tank?"... I'd make at least 2"...>
Or what about putting an "elbow" on top of the Tower to keep heavy rains and leaves out? Would the Elbow restrict air flow some what or not be an issue?
<You could... but as I state, there is little that makes its way into this aperture really>
Many THANKS for your reply and all the wonderful info on your website!!!!!
Merry Christmas to you and your family, Britt Dwyer
<And to you and yours Britt. Bob Fenner>

Re: Bob Fenner question... Pond filtration, pb    12/31/08
Hello again! Thank you SO much for your quick and informative reply!
Everything makes sense now and I think I'm ready to start cutting holes and putting this little puppy together. Unfortunately, I did think of a couple more questions, but this should do it and I will be out of your hair.
1) Will 2,000 or 2,500 GPH be too strong or too fast of a "flow" for this55 gallon Bio-Filter (using a 1 1/2 inch intake line)? I want to make sure that I have enough "dwell time" in the barrel so all the beneficial bacteria has time to do its thing! Best that I can tell, from what I have been reading, I will need to have at least 2,000 GPH (at 12 feet of head) for sufficient flow in my stream/waterfall (roughly 18 to 24 inches wide).
What do you think................is this a problem or not an issue?
<Not likely a problem... if too vigorous, a valve can be employed (best to have one on the discharge... the one to taper... and intake side of the pump anyway... true union fitted, to allow for pump removal...>
2) I plan to have *one Intake line* going into the pond (feeding the pump),
<Mmm... do please read here re pond plumbing:
http://wetwebmedia.com/PondSubWebIndex/pdplumbing.htm
and the linked files above... Better to have at least one other intake... perhaps a "wall" one and if one "bowl" basin, one at the bottom...>
but then (once the PVC line got to the bottom of the pond), I was going to use a "Y" or a splitter so that I could have *TWO separate intakes*. One located towards the pond surface (maybe 6 inches down) and the other intake at mid-level (but at opposite ends of the pond, furthest away from the waterfall).
<Ahh! Very good... I should read ahead>
I plan to have some type of "sponge" pre-filter at the end of each of these intakes.
<Mmm, I would go with a "sieve" type design instead... sponges get clogged too easily, and cause problems... you don't want restriction on the intake of a centrifugal pump>
I figure that these small sponge pre-filters will get quite dirty rather quickly, so I plan to have several extras. Anyway, what do you think..................will having TWO intakes off of ONE inlet line work, or will this cause problems?
<Won't cause problems... is far better than one... which might be
problematic if it were to (too easily) become occluded>
Again, THANK YOU for all your help! You are GREATLY appreciated! I just don't know what I would do without some additional input from a Pro like yourself!
Take care, Britt
<An olde pro... for sure. And FWIW, I do encourage you (though it seems you already have) to look into (Amazon, Home Depot/Lowe's... the library) consumer books on pond building, maintenance... NOW is the time to investigate, believe me... Not later when most all the concrete work is done, the basin/s in place. Cheers, Bob Fenner>

Re: Bob Fenner question, up flow pond bio-filters    12/31/08
THANKS again for all your help!!!! I just printed off several of your articles from the link you gave me ("Pluming Water Features", "Check Valves", etc.), and now I'm moving on to the FAQ's, so by Spring 2009, I *WILL* be ready to tackle this deal and do it right the first time!!!
<Heeeee!>
May God continue to bless you and your family! Happy New Year, Britt
<And to you and yours Britt. BobF>

Question about up-flow filter <Ponds>  7/2/07
Hello sir,
I just finished reading your article on WetWebMedia.com about constructing up-flow filters and it was very helpful. However, I have 2 questions. In your construction diagram, you have labeled an aeration tower and a sediment sump. I don't know what these are. Is the aeration tower a piece of PVC pipe with holes drilled in it to allow water coming in from the pond to leak out into the gravel filtration bed?
Or is it something else?
<Is any given number of mechanisms for super-saturating the incoming water with dissolved gas... often, as you state, just a pipe with inserts in it that water is dropped, sprayed over enroute to the hypoxic stages of filtration...>
Also, what is the sediment sump?
<Is a chamber that allows for the settling out of suspended solids... Often a partitioned sump that incoming to-be-filtered water expands into to allow the removal of these materials to prevent their getting further... Often such traps are fitted with conical bottoms, and automated or manually operated drains to waste>
If you could answer these questions I would greatly appreciate it.
Thank you.
James Allen Clark
<Welcome. Bob Fenner>

ALS 600 Biofilter  12/13/05
Hi Bob,
<Renel>
I am hoping to construct your biofilter.  After looking at several  other
filter ideas, your's is still the best.  I live in So. Cal.  and I think it
will
work out just fine.  Can you give me any dimensions or  measurements for the
ALS 600?
<The "tank" was constructed of either 55 or 60 gal. Polyethylene drums (soda
pop syrup containers), that we cut the tops off of... the plumbing all
schedule forty... the bottom supports from 1 1/4" I.D....>
If you were still in business, I would  purchase one from you.  I
already have a titan 550 sitting around not being  used, so I thought I
would
hook it up to the finished filter.  Would that  be sufficient?
<Don't know the spec.s on such... should be (with sufficient actual
head/flow) about one gallon per cubic gallon of filter media per minute...>
Thank you for any help you are able to give me.
Renel
<Bob Fenner>

Re: ALS 600 Biofilter  12/14/05
Thanks for the info Bob.
Some of the technical stuff like schedule 40 pipe etc. I will leave to
whomever I can get to help me with this project.  I have raised children  
and kept
house until recently, so plumbing was not one of my specialties.
<Your knowledge and skill set is much larger than mine... not to mention
more pertinent>
I can always go to Home Depot or Lowe's and ask them what I need.  I  am not
totally helpless though, and have put together several outdoor projects,
including the 1,000 gal. pond we have.
<This filter will be a breeze comparatively>
The one thing I didn't quite understand was "the bottom supports from 1  
1/4"
I.D".  What do the bottom supports look like?
<Sorry re... and don't have a pic or drawing... but let's see: made of
"tees", elbows and sections of cut pipe... the tees turned down as supports,
the els to make corners, the pipe to join all together... doesn't need to be
solvented, just "jammed" together>
Is there a  tray in there?
<Of a sort. We used sturdy (comes in a couple formats, the styrene is the
one you want if using this) of egg-crate (aka louver... from HD, Lowe's...),
for support, but most any plastic of strength will do... if you use fine
filter media, a layer of fiberglass screen over this is a good idea... can
be attached with a glue gun, silicone seal, or monofilament...>
It looks like the media is approximately 3/4's large and 1/4 small (pea
gravel).
<Most folks use this, yes... but there are a few alternatives... these are
discussed on WWM>
The aeration tower looks like 3"-4" PVC, the intake  from pump 1"-1 1/2",
the gravity overflow 2", and the backwash 1 1/2"-2"?
<Yes to these measures>
  Also, no divider
between the large and small media, right?
<Correct>
Sorry about all the questions.
Once again, Thanks so much.
Renel
<Thank you for asking for clarification. Bob Fenner>

Re: ALS 600 Biofilter  12/14/05
I can't thank you enough Bob.  I did read WWM and  see some other choices
for
media.  I like the pea gravel idea  because it seems so natural, but will
reread WWM and reconsider.
<Hotay... the gravel is a good choice (if available) for a few sound
reasons... but many folks like fibrous material/s for ease of cleaning,
moving about... brushes are neat, but expensive to purchase, and don't do
much to bolster alkaline reserve...>
Many thanks,
Renel
<Welcome. Bob Fenner>

Re: Biological Filter (for pond "down under")
Bob,
Thank you very much for your quick reply.
I had read your article and found it & your entire site excellent.
My existing filter has crushed basalt (we call it blue metal) about
1/2 inch in diameter. I was going to also use this for the new filter
but it was suggested to me that crushed volcanic rock would be a
much better medium (like the gravel sometimes used for paths).
Again about 1/4" to 1/2" in size. It's benefit over blue metal, would
be a much more jagged surface giving many 'nooks & crannies' for
the bacteria to grow & multiply.
<A toss up as you've probably heard the controversy... the blue metal/basalt might actually be the better of the two... having more clay/feldspar mineral to contribute to the system/processes of filtration... and likely being easier to wash/backwash than the likely more dense, angular (but microscopically very much smoother) volcanic rock... I would likely use at least a small amount/layer of the basalt in addition to, if not in the place of the volcanic> 
Bob, a couple of other questions.
Is aeration of the filter an asset (via an air blower)?
<Yes... in particular a worthwhile addition if the water issuing from the filter is bereft of oxygen, decidedly of lower pH... And construction of an "airlift" of compressed air (not blower) can be a great asset for helping raise, clean a reverse-flow type arranged pond filter of size>
Any suggestions for a method for holding media off bottom, giving
say a 6" free space on bottom for solid settlement etc.?
<All sorts. If you can afford it, there are some industrial grids made of various plastics, resins, that aren't too hard to cut/shape to fit your tank (which is circular if memory serves, and likely polythene, perhaps fiberglass/resin). I would raise it up on block (cementatious) probably, though PVC or ABS cut piping with "V" notches (to allow water circulation), fittings could be made, found to do the job>
I was also thinking of using plastic 'shade cloth' (hope that translates)
to sit the media on (once I figure out the support system). Do you
have any experience as far as possibility of deteriation over time
due to being under water etc. or other problems?
<I do, and this shade cloth is really very useful. Does last, not toxic>
I tried to subscribe to your newsletter but it would not connect!!!
<Hmm, will send this along to Mike and Zo (my friends/mates) who know about such things (As I say, I am NOT in the computer business, I'm in the ornamental aquatics content biz... the net, devices to/from it are only TOOLS>
I really, really appreciate your help.
Thank You
David
<Be chatting. Bob Fenner>

Biological Filter
Hi Robert,
I'm in Australia and would appreciate your advice.
I have just been given an old fibreglass rainwater tank (approx 1100 gals & 8 ft in diam.). 
I am going to use it as an additional biological filter for my 10 yr old 6000 gal koi fish pond. It will be an upflow system through a crushed rock medium gravity feeding to my existing filter (it will have a bottom drain for cleaning). In the future, if needed, I will add a vortex settlement tank at the start of my system.
<Many possibilities... the settlement one is good... with brushes, some sort of material as a "pre-filter"... maybe dacron "batting" material from a yardage store.>
The outlet from this new tank will need to be about 4 ft from the bottom to enable gravity feed to existing filter.
I have 2 questions:-
1) I have read varying reports on filter media depth and would love your perspective on the optimum thickness?
<Mmm, depends on make, diameter, and to some extent on "roundness" of the media. Have you read over this: http://www.wetwebmedia.com/pndfltmedia.htm
re filter media for ponds?>
2) Because of depth of water in this new tank (4 ft) will it affect bacterial growth if say there was 2ft of water over the top of this media?
<No problems... better to have a large amount of water than have difficulties with too much media, clogging/channeling... Other possibilities include stratifying media types, grades over a screen... even using lightweight "beads" or plastic "rings" as per sewerage treatment... even floating plant material in the water column above (like hyacinths, myriophyllum... many more). Some of these are covered on WetWebMedia(.com) under the "Planted Aquarium" index>
Thank You very much,
David McPherson
<Let's keep chatting this over if anything is unclear. Bob Fenner>