Water Changes

[MitchM]

BOD (biological oxygen demand) and COD (chemical oxygen demand) may be better determinants of water quality, but I don't know any means of easily measuring them.

 

[Meyer Jordan]

BOD (biological oxygen demand) and COD (chemical oxygen demand) may be better determinants of water quality, but I don't know any means of easily measuring them.

Hanna instruments has a COD test available. here is what they have to say about BOD and COD-
"Biochemical Oxygen Demand (BOD) is an empirical test that determines the relative oxygen requirements of wastewater, effluent and polluted waters. BOD tests measure the molecular oxygen utilized during a specified incubation duration for the biochemical degradation of organic material (carbonaceous demand) and the oxygen used to oxidize inorganic material such as ferrous iron and sulfides. The most common BOD test consists of a 5 day period in which a sample is placed in an airtight bottle under controlled conditions temperature (20ºC ± 1ºC), keeping any light from penetrating the sample to prevent photosynthesis. The Dissolved Oxygen (DO) in the sample is measured before and after the 5 day incubation period, and BOD is then calculated as the difference between initial and final DO measurements. BOD can be considered a more "natural" test in determining the oxygen required to oxidize organic matter, however it does not account for rapid changes in conditions. COD is often preferred for daily analysis since it is inherently more reproducible, accounts for changing conditions and takes a short time to complete"

I prefer the 'Jar-in-the-closet' method (as I call it) for testing BOD. I have never tested COD as, barring exceptional external pollution, it should stay fairly stable. BOD, on the other hand, can vary considerable based on the amount of organics that are added and/or removed from an aquatic environment quickly affecting water quality. Here is where I disagree with Hanna.

 

[MitchM]

I wasn't aware of Hanna's photometer for testing COD (plus other parameters). Thanks Meyer.
At $1000 US, it expensive compared to what we normally spend on testng equipment, but compared to how much we spend on additional equipment and bogus remedies, it may be money well spent.
This holiday season has got me spending too much time in traffic, ect, so I haven't had as much chance to read over things as I would like, but I'll catch up...

This thread is about water changes after all, so I would like to keep things relevant to the topic and to other readers and their ponds

.

 

[crsublette]

So there was a thread on facebook talking about water changes, how much and how often. Is this something that most people do? I only add water when the pond gets low, usually a few inches maybe 1x a month but I'm curious about the reasoning behind it.

Post#33 on thread, Water Changes... My approach, thoughts, and recommendation.

 

[crsublette]

I do the same JB and did the same when I started my pond last year mgmine. I just keep reading that there are people who swear that frequent water changes (up to 30%) is a must to reduce various issues. I was just curious about the reasoning behind it.

Very circumstantial... that is the reasoning behind it... but the people that "swear by it" probably would say otherwise much the same as folk saying no water changes are ever needed... I have seen otherwise from a wide context of circumstances... Usually the type of "swear by it" statements are made due to a mentality of "better safe than sorry" or KISS... even if the "sorry" part has 0.001% chance of occurring or the other options are really are quite simple, they will still "swear by it" because there is that chance or "it really is not as simple"...

Aaahh, the fun of trying to garner advice from forum reading. ... which it is all good... the varying perspectives are enlightening one way or the other...

Best answer for you is what makes the most sense to you in your situation and then do that what makes most sense to you.

I hope that makes sense.

 

[crsublette]

I really think people should also define their terms, such as "muck in pond". In context of my circumstance, due to lack of significant wind blocks and high winds and surrounded by agriculture, after a strong day of 40mph wind, there is a good thin film of soil in my pond. After about a week of this type of weather, there is at least about a 1/4 inch of soil in my pond. Technically, soil is minced up rock material. Plant nor rock eating microbrial life will make this soil disappear before it accumulates quite significantly in my little pond. Still, I only quite sparingly and lightly "vacuum" my little pond maybe once a month.

 

[crsublette]

I guess you maybe have to see it to believe it? We have a completely rocked pond (large boulders line the sides) and the bottom is covered in a layer (shallow shallow shallow!) of gravel. Like so shallow you can swish your foot once or twice and see liner. When I get in the pond (getting in one last time this weekend - gonna be a bit chilly!) I make a point of kicking things around a bit. I will occasionally stir up a bit of silt, but often there is absolutely nothing. And certainly no "toxic gunk".

I think I posted this picture once before when this topic came up - here's a shot from the side of my pond looking straight down. You can clearly see the gravel at the bottom. This is my "step down" spot - the shelf at the bottom left is about 12 inches deep - at the center of the photo it's just over three feet deep.

View attachment 86945

Love it!! Exactly what I did with my little pond.

 

[crsublette]

This is what I wish I knew before I built my pond. I discovered that with the shape of my pond and having the pump in the skimmer I wasn't getting any water circulation at the bottom. I have now been adding either a bottom pump or air stones to circulate the water at the bottom and I have noticed there isn't as much need for me to vacuum.

You are definitely not alone in that sentiment I garauntee!

This is where important to garner as much wisdom from reading fellas whom have done this for many years!

 

[crsublette]

This forum does not have an upload feature for documents, only photos. Perhaps they could add it at some future date. HINT! HINT!

I would be happy to send you a copy by email.

For future note, this is why there are free file hosting servers, which will allow you to hyperlink to a file for others to download. Incredibly useful service. MediaFire is an excellent one that I have used for about 18 years now. ... ugh... Yes, I am that old....

 

[crsublette]

Are we talking about the same thing, MitchM? The key feature of a trickle tower is the colonization of anaerobic bacteria that convert Nitrate into Nitrogen gas which is then off-gassed. Some people confuse these with Bakki showers which are a completely different thing.

A Trickle Tower is designed to develop areas of low or no Oxygen to foster the growth of anaerobic heterotrophic bacteria that have the ability to convert Nitrate directly into Nitrogen gas. Thus the purpose of a Trickle Tower is Nitrate reduction. Extremely low water flow (trickle).

Hmmm.... This is incorrect and Manky Sanke's article demonstrates a denitrification reactor rather than what would be referred to as a "trickle tower".

Actually, attempting to call a Trickle Tower an anaerobic device is a corruption of the term in aquaculture.

For context, within our water garden hobby, since this hobby and aquaculture industry both involve fish husbandry (which is the primary focus), the most suitable context for definition of "Trickle Tower" would be from the aquaculture industry.

And... the predecessor to the Trickle Tower was the Rotating Biological Contact wheel devices... Neither of them were initially conceived as to be used an an anaerobic device.

And I quote:

http://www.mediafire.com/view/8rgw5erplxcp6os/Biofiltration-Nitrification_Design_Overview.pdf

Slide 43:

"Trickling filters consist of a fixed media bed through which a prefiltered wastewater trickles down across the height of the filter. The wastewater flows downwards over a thin aerobic biofilm and dissolved substrates diffuse into the biofilm where they are consumed by the nitrifying bacteria. As it trickles over the media, the water is continuously oxygenated and carbon dioxide is removed by the ventilated air. Trickling filters have been widely used in aquaculture, because they are easy to construct and operate, are self-aerating and very effective at off gassing carbon dioxide, and have a moderate capital cost. Eding et al. (2006) has published an excellent review on the design and operation of trickling towers.

In municipal waste water treatment systems, trickling filters were traditionally constructed of rocks, but today most filters use plastic media, because of its low weight, high specific surface area (100–300 m2/m3) and high void ratio (>90%). According to Eding et al. (2006), Boller and Gudjer (1986) judged a specific surface area of 150–200 m2/m3 to be most suitable for the corrugated plastic media they applied in their wastewater treatment research. Similar specific surface areas for plastic media (Bionet 160 m2/ m3; Filterpac 200 m2/m3 and Munters 234 m2/m3) are installed in trickling filters applied in aquaculture (Kamstra et al., 1998)."

 

[crsublette]

Bakki is not really the name of a device. Bakki is the name of a product that describes what the koi hobby refers to as a "shower tower". "Shower towers" are basically just very high flow rated wet/dry biological filters. In wastewater terms, I think the "shower tower" would be referred to as an Ammonia Stripping column due to how hobby enthusiasts want to think how the "shower tower" to functions.

Reason everyone says "Bakki" instead of "Shower Tower" is purely due to how the Bakki product was marketed and so it caught on. There are been many DIY Shower Towers, but you would not call these a "Bakki" since "Bakki" entails particular construction materials.

 

[crsublette]

Awesome thread nonetheless!!! I enjoyed it... until page 11 where I got totally thrown off plus me being quite tired... I will have to return to start reading again at page 11. ... whenever I have the free time, ugh, LIFE!!!

Excellent discussion!!

 

[tbendl]

Good to see you again Charles, it's been awhile. Hope you and yours are well.

 

[Meyer Jordan]

Hmmm.... This is incorrect and Manky Sanke's article demonstrates a denitrification reactor rather than what would be referred to as a "trickle tower".

Actually, attempting to call a Trickle Tower an anaerobic device is a corruption of the term in aquaculture.

For context, within our water garden hobby, since this hobby and aquaculture industry both involve fish husbandry (which is the primary focus), the most suitable context for definition of "Trickle Tower" would be from the aquaculture industry.

And... the predecessor to the Trickle Tower was the Rotating Biological Contact wheel devices... Neither of them were initially conceived as to be used an an anaerobic device.

And I quote:

http://www.mediafire.com/view/8rgw5erplxcp6os/Biofiltration-Nitrification_Design_Overview.pdf

Slide 43:

"Trickling filters consist of a fixed media bed through which a prefiltered wastewater trickles down across the height of the filter. The wastewater flows downwards over a thin aerobic biofilm and dissolved substrates diffuse into the biofilm where they are consumed by the nitrifying bacteria. As it trickles over the media, the water is continuously oxygenated and carbon dioxide is removed by the ventilated air. Trickling filters have been widely used in aquaculture, because they are easy to construct and operate, are self-aerating and very effective at off gassing carbon dioxide, and have a moderate capital cost. Eding et al. (2006) has published an excellent review on the design and operation of trickling towers.

In municipal waste water treatment systems, trickling filters were traditionally constructed of rocks, but today most filters use plastic media, because of its low weight, high specific surface area (100–300 m2/m3) and high void ratio (>90%). According to Eding et al. (2006), Boller and Gudjer (1986) judged a specific surface area of 150–200 m2/m3 to be most suitable for the corrugated plastic media they applied in their wastewater treatment research. Similar specific surface areas for plastic media (Bionet 160 m2/ m3; Filterpac 200 m2/m3 and Munters 234 m2/m3) are installed in trickling filters applied in aquaculture (Kamstra et al., 1998)."

Here we go with semantics again. A Trickle Tower and a Trickle Filter are two (2) different configurations designed to accomplish two (2) different things.

 

[crsublette]

Here we go with semantics again. A Trickle Tower and a Trickle Filter are two (2) different configurations designed to accomplish two (2) different things.

Yep, and I use aquaculture text (which has the most in common to our context) to support my semantics, and no where is there a suggestion that a Trickle Tower is, as you stated in post#206, "a Trickle Tower is designed to develop areas of low or no Oxygen to foster the growth of anaerobic heterotrophic bacteria that have the ability to convert Nitrate directly into Nitrogen gas".

And my post above, stated by Ebeling, uses the terms "trickle tower" and "trickle filter" interchangeably.