High pH

This is just to add to what was said in a previous thread. I talked to my
wife (who is a geologist like me, but also has experience with waste water
treatement) about high pH levels some here have mentioned, and she pointed
out that high pH can also be an indication of high waste loads in the pond.
If the bottom of your pond (or rocks at the bottom of the pond) is covered
with black sludge and/or rotting detritus, you might want to try to clean
that up, and do a partial to full water change to see if that corrects the
problem. Just a suggestion.

George

George,

Does the sludge and rotting stuff push the pH down or up? I thought
it would move things in the acid direction.

Jim

in an aquarium it kills the biofilter and the nitrites which are acid
plus the organic debris which is acid drive the pH down. I would
imagine in a pond the same thing would happen, altho if there is just
high ammonia, that would drive the pH up.

I have never let my ponds get to sewage stage yet. Ingrid

On Tue, 3 Jul 2007 07:17:47 CST, Phyllis and Jim
<> wrote:
>Does the sludge and rotting stuff push the pH down or up? I thought
>it would move things in the acid direction.

<dr-> wrote in message
news:468a6176$0$1346$. com...
> in an aquarium it kills the biofilter and the nitrites which are acid
> plus the organic debris which is acid drive the pH down. I would
> imagine in a pond the same thing would happen, altho if there is just
> high ammonia, that would drive the pH up.
>
> I have never let my ponds get to sewage stage yet. Ingrid
>
> On Tue, 3 Jul 2007 07:17:47 CST, Phyllis and Jim
> <> wrote:
>>Does the sludge and rotting stuff push the pH down or up? I thought
>>it would move things in the acid direction.

That is true. However, few people build their ponds with an included
undergravel filter as is found in most aquariums. Most people who have a
biofilter (such as myself) build it as an enclosed structure or vessel.
Within that vessel, water is constantly being fed into it, bringing with it
oxygenated water. The sludge I was referring to occurs on the bottom of
the pond where detritus settles out and can become anoxic in areas with
little or no water flow, especially where there are rocks piled up. If
your biofilter is working properly, the nitrate and ammonia levels will
usually remain low, but the pH, over time will begin to rise because of the
build up of sludge on the bottom. That's my understanding of what happens.
It's a good argument for using sludge-loving bacteria in your pond to
prevent such build up from occurring, and also argues for increasing water
flow in areas where such build up can occur.

George.

that sludge is anaerobic, and anaerobic digestion releases hydrogen
sulfide H2S, which when combined with water is sulfuric acid H2SO4 ...
an acid. Nitrogen is released, bubbles rise to the surface and leave
the pond.

I would like somebody to do an experiment!!!! Ingrid

On Tue, 3 Jul 2007 14:57:25 CST, "George" <>
wrote:
The sludge I was referring to occurs on the bottom of
>the pond where detritus settles out and can become anoxic in areas with
>little or no water flow, especially where there are rocks piled up.
the pH, over time will begin to rise because of the
>build up of sludge on the bottom. That's my understanding of what happens.

>On Tue, 3 Jul 2007 14:57:25 CST, "George" <>
>wrote:
> The sludge I was referring to occurs on the bottom of
>>the pond where detritus settles out and can become anoxic in areas with
>>little or no water flow, especially where there are rocks piled up.
>the pH, over time will begin to rise because of the
>>build up of sludge on the bottom. That's my understanding of what happens.
>On Wed, 4 Jul 2007 11:33:21 CST, dr- wrote:

>that sludge is anaerobic, and anaerobic digestion releases hydrogen
>sulfide H2S, which when combined with water is sulfuric acid H2SO4 ...
>an acid. Nitrogen is released, bubbles rise to the surface and leave
>the pond.
>
>I would like somebody to do an experiment!!!! Ingrid
>
I was thinking similar. My understanding is when one has a build of sludge
one is heading for a pH crash, where it goes acidic. I suppose that could
be because the breaking down of sludge is also using up the buffering/KH.
~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us

"~ jan" <> wrote in message
news:...
> >On Tue, 3 Jul 2007 14:57:25 CST, "George" <>
>>wrote:
>> The sludge I was referring to occurs on the bottom of
>>>the pond where detritus settles out and can become anoxic in areas with
>>>little or no water flow, especially where there are rocks piled up.
>>the pH, over time will begin to rise because of the
>>>build up of sludge on the bottom. That's my understanding of what
>>>happens.
>>On Wed, 4 Jul 2007 11:33:21 CST, dr- wrote:
>
>>that sludge is anaerobic, and anaerobic digestion releases hydrogen
>>sulfide H2S, which when combined with water is sulfuric acid H2SO4 ...
>>an acid. Nitrogen is released, bubbles rise to the surface and leave
>>the pond.
>>
>>I would like somebody to do an experiment!!!! Ingrid
>>
> I was thinking similar. My understanding is when one has a build of
> sludge
> one is heading for a pH crash, where it goes acidic. I suppose that could
> be because the breaking down of sludge is also using up the buffering/KH.
> ~ jan
> ------------
> Zone 7a, SE Washington State
> Ponds: www.jjspond.us

Sludge build up increases the total organic carbon and decreases the
dissolved oxygen in the water. Yes it does release H2S, but only when it
goes anoxic (otherwise, it can't support the anaerobic bacteria that
produces that gas). However, the acidifying effect of H2S production is
usually overcome by the changes in TOCs and DO, as well as gas exchange
into the atmosphere, which is where the H2S will end up if circulation and
pond surface area is adequate. Buffers can be depleted which can lower the
pH, but if you have a lot of carbonate rock in your pond (like I do) or
have a concrete pond, a significant reduction in buffering capacity is not
likely to occur. One thing is clear, and that is that a high pH is harmful
to both the fish and the plants in the long run, and should not be ignored.
So keeping sludge to a minimum and maintaining good water flow and
oxygenation is essential to a healthy pond.

George

dr-s...@wi.rr.com wrote:
> that sludge is anaerobic, and anaerobic digestion releases hydrogen
> sulfide H2S, which when combined with water is sulfuric acid H2SO4 ...
> an acid. Nitrogen is released, bubbles rise to the surface and leave
> the pond.

H2S is an acid all by itself, without any need to react with water.
it's SO3 which reacts with water to produce H2SO4. The conversion of
H2S to SO3 is an oxidation reaction, which won't be happening in the
anaerobic areas of your pond. Also, where is the Nitrogen coming from?

George wrote:
> That is true. However, few people build their ponds with an included
> undergravel filter as is found in most aquariums. Most people who have a
> biofilter (such as myself) build it as an enclosed structure or vessel.
> Within that vessel, water is constantly being fed into it, bringing with it
> oxygenated water. The sludge I was referring to occurs on the bottom of
> the pond where detritus settles out and can become anoxic in areas with
> little or no water flow, especially where there are rocks piled up. If
> your biofilter is working properly, the nitrate and ammonia levels will
> usually remain low, but the pH, over time will begin to rise because of the
> build up of sludge on the bottom. That's my understanding of what happens.
> It's a good argument for using sludge-loving bacteria in your pond to
> prevent such build up from occurring, and also argues for increasing water
> flow in areas where such build up can occur.

I can see how that works for small, decorative ponds. But what about
large ponds (say, one that is 100'x40' and 20' deep)?



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"Chris Barnes" <> wrote in message
news:f6j05l$vg9$...
> George wrote:
>> That is true. However, few people build their ponds with an included
>> undergravel filter as is found in most aquariums. Most people who have
>> a biofilter (such as myself) build it as an enclosed structure or
>> vessel. Within that vessel, water is constantly being fed into it,
>> bringing with it oxygenated water. The sludge I was referring to occurs
>> on the bottom of the pond where detritus settles out and can become
>> anoxic in areas with little or no water flow, especially where there are
>> rocks piled up. If your biofilter is working properly, the nitrate and
>> ammonia levels will usually remain low, but the pH, over time will begin
>> to rise because of the build up of sludge on the bottom. That's my
>> understanding of what happens. It's a good argument for using
>> sludge-loving bacteria in your pond to prevent such build up from
>> occurring, and also argues for increasing water flow in areas where such
>> build up can occur.
>
> I can see how that works for small, decorative ponds. But what about
> large ponds (say, one that is 100'x40' and 20' deep)?
>

Large ponds and lakes are a bit different because of the dilution factor,
and because there are usually inflow and outflow routes. If they have
inflow and outflow routes, then the pH can fluctuate during times of heavy
rainfall, but under normal conditions is relatively stable. Having said
that, large ponds and lakes in temperate zones tend to stratify and then
overturn with the changing seasons. Large ponds and lakes in sub-tropical
to tropical zones rarely overturn, and so remain stratified for long
periods of time, which causes a buildup of gases in the lower levels,
particularly of CO2 and H2S. Disturbing those layers (say due to an
earthquake or landslide/slip) can cause a release of large quantities of
built up gases all at once, which can potentially be a dangerous situation
for lifeforms living nearby. But for the size of the pond you are talking
about, I don't think that is much of a problem. There may be some minor
stratification, but if it is in a temperate zone, it will overturn during
the spring and fall, and naturally get rid of those gases.

George