Chicken Grit, pond filtration   6/4/08
I just built a new pond. Its about 25 feet long, 12 feet wide at the widest, tapering to 5 feet wide at the narrowest. It's 18 inches deep at
the narrow end tapering to 30 inches deep at the wide end. It's roughly 2200 gallons. I'm using an Ebara pump, rated at about 4300 gph to an 18
inch Hayward sand filter filled with 100 lbs of crushed granite Chicken grit. The pieces are roughly 1/8 inch to 3/16 inch.
<Mmm>
I've only had the filter up for a couple days and the water is starting to clear. I saved about 100 gallons of my old pond's water for a bacterial boost.
<Good technique>
Unfortunately we've been hit by torrential rains since I filled my pond and have been unable to complete the waterfall or anything else, yet. I
was wondering how well the crushed granite would perform over pea gravel.
<Both can be problematical... in terms of "compacting" and channeling... lighter media is highly preferable>
The pea gravel sold in my area is more like ½ to ¾ inch gravel and with pieces that large, I don't see how they will do much filtration. I
backwashed the filter this afternoon and the water was still relatively clear. I don't have any fish in this pond yet. My son managed to catch
all my Koi from my old pond and carry them like a squirmy bluegill to the horse tank for safekeeping.
Unfortunately they died from the trauma of an overzealous teenager's handling. Any idea you can throw my way would be most appreciated.
<Best to scoop up not-so-handled "medium" (a foot, foot and a half) Koi in thick (4 mil.) fish bags (see your dealer or save old ones) and move with minimum water. Larger Koi still, esp. ones that have been handled from time to time, can be picked up, carefully, from underneath... there is a great deal that can be related re technique here>
I'm kind of a jack-off-all-trades, and I prefer to make whatever I can. My drywall bucket bio prefilter is my first engineering marvel and is still in use in my new pond. It's installed after the mini skimmer with a 900 gph pump discharging toward the waterfall site, so there aren't any dead spots.
<Ah, good. Again, I would look into "more appropriate" filtration methods here period. Pressurized filters, the pumping to run them... is too expensive and inefficient in this day and age... Do check out the Net, libraries for modern books, articles on other means. And we'll chat if you'd like re. Bob Fenner>

Pond Filter Design
Hi Robert,
I read your article in Wet Web Media.com. I think your ideas make a lot of sense. Do you have more details on the construction of this simple idea including the filter media to use.
<Do... in my files at the S. Cal. res... but am out of town... Are you looking for something in particular? We started with encouraging folks to use crushed rock, graded... some people advocated the use of igneous... we eventually found, cut with a band saw, plastic honey-comb used in cooling towers...>
Thanks in advance. I'm installing an 1100 gal fiberglass pond.
Best regards, Horst Riedner
<Bob Fenner>

Rocks, bricks... as Pond Filter Media
Thank you for offering to answer my questions.
I am considering using refractionated bricks or cinder blocks (broken up) as
a filter media.
Will either of these hurt the fish in any way?
Do you see any reason why I should not use one or the other?
Thanks!
Cindy
<It's possible these materials may alter your water pH and alkalinity... but easy to test for... and it may well be that your source water is deficient in alkaline reserve and this might well be a good way of bolstering/supplying it. I definitely would do a chemical AND "bio-assay" with a bit of the proposed filter material in a container, testing the water before and after for pH and alkaline reserve... and adding a few (likely "feeder" gold)fish to the mix to see how they do. Bob Fenner>

Pond Filters, media
Last March(03) my wife and I purchased a 15ac. 200 year old farm house (NC).  The last owner had had the "yard guy" create a 10,000+ gal. fish pond. We were told we only had to clean the filter two or three times per year.
<Some types of systems, yes... some even less frequently... depending on what one means by "clean">
The filter is a circular gray(3 ft dia. and 4 ft deep), 250/300 gal., up flow system with seven, 2 inch thick plastic fiber mats. I cleaned the filters every 30 days during the first summer and let it go during the winter (5 months/ Nov. thru march). There were no fish in the pond to start but my wife added feeder goldfish 1/2 through the summer and they have done very well. We now have 50 to 100 " good size" goldfish.  My question is... what is the best filter media to use to keep a pond this size clean. Ease of cleaning is my highest priority.
<Good question... as you will find, there is an article/discussion of various pond filter media archived on WWM: http://wetwebmedia.com/PondSubWebIndex/pdfiltmedia.htm
Criteria for your particular choice include the make-up of your water (chemical, physical), cost/availability of media there, the degree of "cleanliness" you desire... and what other means you're willing to apply (e.g. other filtration modes like UV, ozone...) to get you where you want to. What you have now is likely 80 some percent of so what you can hope to achieve with the current set-up... and I might just add some live plant material and leave the rest as is. This will be fine along with partial water changes, vacuuming of debris/overburden during warm months and careful feeding of your goldfish, to keep the system biologically (and aesthetically) sound. 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>

pond filtration
hi,
Just wanted to ask for your opinion on the emperor aquatics bag and bio pond
filters.
(http://www.emperoraquatics.com/pondbagbio.html) thanks
<Of products of their kind, they are superlative. I have used these bags as "first lines of particulate and filth (fish, invertebrate wastes) in aquaculture, live-holding facilities for many years. They really work. Bob Fenner>

Foam Filters? (this time for ponds)
Hi Bob,
I recently bought a home with a small Koi pond and am trying
desperately to make sure they survive... My problem is this: the
filtration system pumps the water up into a tank on the bottom of which
are two layers of polyurethane foam with a hole cut in the center
through which the hose from the pump goes pumping the water under the
foam.
<Yikes... hard to clean>
Near the top of the tank is a hose returning the water to the
pond. The previous owners left instructions on when and how to clean
the tank and replace the foam however I am running out of foam and can
not seem to find a source of this "biological filter foam".
<You can get it from a yardage store (as in sewing) or furniture or large hardware store outlet... it's likely just open-cell polyurethane sheet... can be cut in a few ways>
Can you
recommend a place to get more or a better material through which the
water should filter.
<Yes... look into "batting material" from the yardage store...>
I seem to be in trouble because for a few months
an extra fish temporarily lived in the small space over taxing the
environment leaving a lot of algae and other plant life living on the
pond liner (on the sides)and causing the pump and or hoses to slow the
water flow to a trickle every few days. The only way I seem to be able
to clear it up is to force water through the hoses and clear them but
every 3 or 4 days I seem to have to do that again. This was not true
for months before the now gone visiting fish over taxed the pond's
capacity... What do I do now?
<Mainly a seasonal problem... with cooler weather, less sunlight all should settle down>
Replace the filter material more
frequently until it clears up or what?
Help!
Thanks for your time,
Jim Gallagher
<I would really like to start way, way back (watch yourself, don't fall in the pond...) and have you read through the Pond Index on our site: www.WetWebMedia.com: http://wetwebmedia.com/ponds.htm 
and particularly all the sections on pond filtration, starting here: http://wetwebmedia.com/pndfilts.htm
Don't despair, and let's not "band-aid" what you have here, but work toward a better (cost to run, time, overall water quality improvement) solution with me here. Bob Fenner>