Are water changes really necessary?

Discussion in 'Pond Archive' started by Joan, Apr 13, 2008.

  1. Joan

    Joan Guest

    Hi, ponders! It's that time of year again when I start re-thinking
    how I've been managing the pond and nervously watching the fish
    closely for health issues. I've been reading, which always confuses
    me, so now I'm wondering:

    Do you really have to do partial water changes in ponds if the water
    chemistry is okay? My pond is probably about 1500- 2000 gallons, only
    about 12 goldies, pH solid at aroun 8.5, alkalinity around 100, no
    ammonia or nitrite, lots of plants, a good waterfall, a nice
    mechanical/bio filter.

    Do I really have to drain the pond every few years for a major
    cleaning, or can I just scoop the gunk up off the bottom with a net?

    It took so long to get the water just right; I hate to rock the boat.


    Joan in Oregon, always appreciative of you guys.
    Joan, Apr 13, 2008
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  2. Joan


    I top up my pond. I change about 1/3 each year. I have a veggie filter drags
    "stuff" out of the pond. After 8 (9?) years I can still see folds in the liner at
    the bottom of the pond (4'). My koi stir up any sediment and the pump gets it into
    the veggie filter and I remove the mulm with a shop vac. My pond is netted and there
    really arent a lot of trees nearby to dump leaves etc into the pond.
    I have nice lake water, but there is chlorine/chloramine and I am not thrilled with
    having to put sodium thiosulfate into the pond. My fish are healthy. Ingrid
    , Apr 14, 2008
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  3. Joan

    Reel McKoi Guest

    "Joan" wrote in message

    (brevity snips)
    You'll surely get different opinions on this subject. I believe DS
    (dissolved solids) build up in the water that should be removed. Plants and
    filters don't necessarily remove them. I do partial water changes on both
    my ponds and a yearly or every-other-year cleanout. Mulm builds up on the
    bottom that the pump doesn't get, even though the fish may stir it up. I've
    never had a fish die with these total cleanouts. In fact the clean fresh
    water almost always stimulates them to spawn.
    That stirs up foul gasses which are not healthy for your fish and leaves all
    the "fines" behind. It also doesn't remove all the dissolved solids in the
    What was it before it was "just right?" My GF and koi have thrived and
    spawned in water from a PH of 7.6 to 8.2. Your 8.5 is a little high. Just
    curious, why do you keep it so high?
    Frugal ponding since 1995.
    rec.ponder since late 1996.
    Zone 6. Middle TN USA
    ~~~~ } ~~~ }
    Reel McKoi, Apr 14, 2008
  4. I have had a small stone and clay pond in my garden for nearly 30
    years. Some of the water is "changed" every time it rains because it
    has an overflow. Occasionally I scrape the leaves off the filter inlet
    but that's all I ever do.

    Stephen Wolstenholme, Apr 14, 2008
  5. Joan

    Joan Guest

    The pH comes out of the tap at around 7, but the alkalinity is
    approximately zero, so I have no buffering capacity unless I add some
    buffer. I try to keep the alkalinity at around 100.

    I'd prefer that the pH be a little lower than 8.5, by the time I've
    gotten the water suitably buffered, the pH is up. I use the
    commercial product "Buff it Up" for ponds. Dissolves nicely and
    doesn't cloud the water, and keeps the alkalinity up for longer than
    sodium bicarbonate. The pH stays nice and stable, varying hardly at
    all from day to day, and even not varying much from AM to PM.

    I do get a lot of string algae in the pond, which I take out as I can,
    but it keeps on growing. I don't mind it as long as it doesn't get
    too carried away. But I suspect that it pulls a lot of CO2 out of the
    water during photosynthesis, which pulls the pH up by the end of the
    day. I do make it a point to keep the submerged algae under control
    so it doesn't drive the pH up too too high by the end of the day.

    Joan, Apr 14, 2008
  6. Joan

    Joan Guest

    Okay, thanks. How often do you do the partial water changes, and what
    percentage do you change?

    When you do the cleanout, what do you do with your fish?

    Joan, Apr 15, 2008
  7. Joan

    Joan Guest

    Thanks, Steve. 30 years is a long time, so you must be doing
    something right. Do you have fish in there?

    Joan, Apr 15, 2008
  8. Joan

    ~ jan Guest

    As Carol mentioned, lots of various answers, and your situation/environment
    and water source all have to be considered. There are different things you
    can get away with based on what kind of pond and fish you have. Koi only
    ponds the latest is to do a continual flow, people are using carbon filters
    for the input with the output flowing to water the garden in some way.

    Those who mix fish & plants can get away with less extremism. How many fish
    to gallons makes a difference. I feel I'm on the line in the koi ponds, so
    I do a 10-15% water change once/week. The goldfish pond, with much less and
    smaller fish, once every other week.

    In my case though, doing a water change out keeps the buffering up,
    decreases heavy metals and can reduce parasites & bacteria, imo.
    Better would be a shop vac, as all the gunk, plus fines, are suck out of
    the pond. If you're just talking a few leaves not a problem. Draining the
    pond is not a necessity, nor preferred, if you can keep the bottom clean.
    That's why small frequent water changes are the mantra of most pond clubs.

    When I first got into ponding one of the senior club members compared not
    changing one's pond water to staying in a room without opening the windows
    now and again. Or imagine having your car on recir. air after you've just
    taken the family out for a Mexican dinner. ~ jan
    ~ jan, Apr 15, 2008
  9. Joan

    Reel McKoi Guest

    "Joan" wrote in message
    For buffering have you tried something more natural like oystershell chicken
    grit or small limestone rocks? I found neither one raises the PH much but
    does buffer the water and keeps the PH from dropping. Both keep the water
    above 7.

    Frugal ponding since 1995.
    rec.ponder since late 1996.
    Zone 6. Middle TN USA
    ~~~~ } ~~~ }
    Reel McKoi, Apr 16, 2008
  10. Joan

    Reel McKoi Guest

    "Joan" wrote in message
    About once a month I drain off about a third of the water. We don't really
    measure it. Then slowly refill from the hose using a dechlorinator. We buy
    the crystals and mix our own. Or you can degass the water by running it in
    slowly over a trashcan lid exposing a thin layer of water to the air. That
    is if you have something to set the lit on over the water. You can also add
    water by letting it run down a waterfall. If you have chloromines in your
    water that will not work.

    When we do a draindown all the fish go in to an aerated child's kiddy pool
    of 1/2 pond and 1/2 fresh water with a hardware cloth surround and net over
    the top because fish jump. We also have too many predators here not to net
    the top. I add plants and a floating cooler lid for them to hide under. They
    go back in the next morning.

    Frugal ponding since 1995.
    rec.ponder since late 1996.
    Zone 6. Middle TN USA
    ~~~~ } ~~~ }
    Reel McKoi, Apr 16, 2008
  11. Joan

    Joan Guest

    Thanks, Jan.

    [respectfully snipped for bandwidth]

    Glad to know I don't have to drain the pond.

    I did get an Oase PondoVac, which I am trying to get to work right,
    but it's being a tempermental pain in the neck. In the meantime, I
    know I have to be careful about fines and hydrogen sulfide gas, so I'm
    net-cleaning the bottom just a little at a time, so I don't stir too
    much up at once. I do have a good filter that I think will trap much
    of the stirred up fines, and also a UV sterilizer.

    Okay, I guess you've convinced me though. I'll have to start doing
    small water changes.

    Fortunately, I live in Pacific Northwest like you, where we get plenty
    of rain in the fall, winter, and spring, and the pond has a nice
    overflow, so I think we've been getting some water exchange that way.

    Joan, Apr 16, 2008
  12. Joan


    your tap or rain water has heavy metals?
    The parasites and bacteria are ON the fish, not usually free in the water.
    up here in the frozen wasteland one DOES NOT open the windows all fall, winter and
    spring. instead we use air exchangers. a veggie filter is like an air exchanger and
    the surface of the water exchanges gases.

    I think more fish die each year from people forgetting that the water is running than
    in ponds with a veggie filter. Ingrid
    , Apr 17, 2008
  13. Joan

    ~ jan Guest

    You must live on the wet side of the state? I've yet to see a
    rain heavy enough to give me overflow here on the East side. ;-) ~ jan
    ~ jan, Apr 17, 2008
  14. Joan

    Reel McKoi Guest

    "Joan" wrote in message
    Rain, containing no minerals, will soften your water, washing out your
    buffering capacity and lowering your PH. Check after a heavy rain.

    We can't use the pond vac in our ponds because one pond is too deep and in
    both, and the "stuff" at the bottom clogs in the hose. If these vacs work
    for you - more power to you! :)

    Frugal ponding since 1995.
    rec.ponder since late 1996.
    Zone 6. Middle TN USA
    ~~~~ } ~~~ }
    Reel McKoi, Apr 17, 2008
  15. If it doesn't overflow, where does it go? Does all the rainfall
    Stephen Wolstenholme, Apr 17, 2008
  16. Joan

    ~ jan Guest

    It could, Columbia River, heavily polluted by slag from Canada. Why we
    filter it.

    I have no idea what the OP has, so always take that into consideration when
    offering advice.
    Not if their slime coat & immune system is working. Parasites have free
    swimming cycles and bacterium blows in the wind, and like parasites ca
    enter the water on critters' feet/bodies.
    Apples and oranges, square footage, I bet there are less people in your
    house space-wise as there are in fish in your pond.
    I disagree, there are water timers that auto shut off for the forgetful.
    Plus it goes against all documentation to advise not doing water change
    outs. Noga surely recommends them? He, I believe, recommends the small
    frequent water change, as would I, because it doesn't change the temp, or
    pH by much, and that kills more fish than forgetful people, who probably
    shouldn't own pets in general. ;-) ~ jan
    ~ jan, Apr 17, 2008
  17. Joan

    ~ jan Guest

    Speaking of rain, that can really lower the buffering.... but you said
    you've checked it straight from the tap? ~ jan
    ~ jan, Apr 17, 2008
  18. Joan

    Joan Guest

    For buffering have you tried something more natural like oystershell chicken
    What is oystershell chicken grit?

    Limestone rocks is a good idea. I imagine it will take some time to
    equilibrate, but once it does, it should stay pretty solid. I'd be
    really happy if I could manage to keep the carbonate hardness up
    without the pH going so high.


    Joan, Apr 17, 2008
  19. Joan

    Joan Guest

    Oh! Good idea about running it down the waterfall! I do have an
    in-line dechlorinator I can put on my hose, but running the water
    down the waterfall ought to give me an added measure of security.
    All right, thanks for all the good ideas. I've been nervous about
    disturbing the fish too much, but I know it's a much bigger threat to
    them if their water and pond aren't maintained properly.

    Joan, Apr 17, 2008
  20. Joan

    Joan Guest

    Fortunately, I live in Pacific Northwest like you, where we get plenty
    Ah. Yes, I'm on the wet side.

    Joan, Apr 17, 2008
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