Water Changes

[barryian]

Translation-"Yea, I've done this too!"

Ah ... I'm sure most have. It was just a shock when I returned. All seems well!

 

[MitchM]

The solution to polution is dilution. And water changes replenish trace minerals.

I think we're moving away from that old way of thinking and starting to look at dealing with pollution by processing it within the pond using plants and bacteria instead of using water changes as a means of supplemental fitration.

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[MitchM]

Actually the excess build up of minerals is one reason why I implement an automatic drip water change system in my pond, the other reason is the drip, along with a calculated overflow level, allows me to maintain a perfect water level without having to manually top off the pond.
But in reference to minerals in the water, my source water is on the hard side, and if all I did was manually top off the pond to replace what was lost through evaporation the water in my pond water would eventually get very hard as the pure H2O evaporates leaving the minerals behind, and every time I top up the pond I'd be adding more minerals which would concentrate more and more as only the pure water continues to evaporate.

Have you ever logged an increase of these minerals?
Which minerals are you concerned about?

The only aspect of trickle water changes that appeals to me is that it keeps the pond water level constant.

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[MitchM]

L...

I look at it like this ... If I was in a pool with a floater I wouldn't like it. So I filter it out and get rid of it. And put fresh water in.

..but what if the presence of floaters was keeping your slime coat stable and healthy?

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[addy1]

I think we're moving away from that old way of thinking and starting to look at dealing with pollution by processing it within the pond using plants and bacteria instead of using water changes as a means of supplemental fitration.

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I only do water changes when it rains, the rain water flows in (gutter feed) pond/rain water flows out. So far, 6 years later, the pond/fish/critters are still in good shape. I do have a large amount of plants that take care of the pond.

 

[Mucky_Waters]

Have you ever logged an increase of these minerals?
Which minerals are you concerned about?

The only aspect of trickle water changes that appeals to me is that it keeps the pond water level constant.

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I know my source water is hard, I've tested GH and KH, and we have the tell-tale signs like water spots on dishes in the dishwasher when the salt in the water softener runs out. Also, you can sometimes see an obvious white line of mineral deposits all around the pond at the water line. This line is more obvious after an extended dry hot spell and disappears when it rains or I spray the shoreline with the garden hose. But to answer your question, no I've never actually logged an increase in hardness by allowing the water to evaporate from my pond and allowing minerals to concentrate and then re-testing. However, it's a pretty clear scientific fact that if you evaporate water from a container of water only the pure water and other volatilizes will evaporate leaving the concentrated minerals behind.
As for the exact minerals in the water? That I have never tested, but I'm sure calcium and magnesium at the top of the list.
Regarding the water level, where I live we get pretty hot dry summers (and springs and falls sometimes), It's not uncommon for me to loose 1/2" of water from my pond a day through evaporation and capillary action from the plants growing along the edge of the shore.. Although I've never allowed it to happen, it could take less then a couple weeks for the water to drop below the functioning level of my water skimmer and the pump to start sucking air. Plus I'm just sort of anal about the water level in my pond, I notice a 1/2" drop in the level with a quick glance.

A trickle overflow is such an easy thing to set up and run, I turn a valve on in the spring, and turn it off come fall. And it essentially turns your pond into a flow through design which mimics nature better then self contained pond. The only downside I can see is if your water in metered or you pay a the electric bill to pump it out of a well, then you might notice an increase in your water or electric bill. In my case our water bill is a flat rate, I pay a set yearly amount whether I use it or not.
But if you are one of those who routinely do water changes it's the only way to go, I think the manual drain and fill method is crazy, especially if you have to de-chlorinate the water you are adding.

 

[Meyer Jordan]

it's a pretty clear scientific fact that if you evaporate water from a container of water only the pure water and other volatilizes will evaporate leaving the concentrated minerals behind.

I think that it is important to discuss in further detail exactly what this statement actually means.

"Lake-water composition is influenced by evaporation, among many other factors. As water evaporates, the dissolved minerals are left behind. The more evaporation, the higher the concentration of dissolved minerals (salts) in the water."
Water Encyclopedia

The key word in that statement is "salts".
Since salinity levels of water are determined by the combined total of all dissolved salts, then a simple salinity test is all that is necessary to determine whether or not these salts have reached a level of concern.
Koi/Carp and Goldfish have similar tolerances to salinity. Several separate studies have placed the maximum level of salinity that these fish can easily adapt to at 10 ppt or 0.10 percent. It would take some extraordinary circumstances for a garden pond to reach this level of salinity.
Also to be considered is that plants and other aquatic organisms (and fish depending on the quality of their supplemental feeding) are constantly ingesting these ionic minerals which are necessary for their health, growth and well-being.
An excellent example of what the end results of mineral concentration due to evaporation looks like is the Great Salt Lake in Utah. High evaporation with very little precipitation has created this landmark, but it has taken since the end of the last Ice Age to reach its current state.

 

[MitchM]

Surface runoff will also contribute to raised salinity values, which should not be an issue for our ponds.

 

[morewater]

..but what if the presence of floaters was keeping your slime coat stable and healthy?

.

Bill Murray, Caddyshack................."It's okay."

 

[Mucky_Waters]

I think that it is important to discuss in further detail exactly what this statement actually means.

"Lake-water composition is influenced by evaporation, among many other factors. As water evaporates, the dissolved minerals are left behind. The more evaporation, the higher the concentration of dissolved minerals (salts) in the water."
Water Encyclopedia

The key word in that statement is "salts".
Since salinity levels of water are determined by the combined total of all dissolved salts, then a simple salinity test is all that is necessary to determine whether or not these salts have reached a level of concern.
Koi/Carp and Goldfish have similar tolerances to salinity. Several separate studies have placed the maximum level of salinity that these fish can easily adapt to at 10 ppt or 0.10 percent. It would take some extraordinary circumstances for a garden pond to reach this level of salinity.
Also to be considered is that plants and other aquatic organisms (and fish depending on the quality of their supplemental feeding) are constantly ingesting these ionic minerals which are necessary for their health, growth and well-being.
An excellent example of what the end results of mineral concentration due to evaporation looks like is the Great Salt Lake in Utah. High evaporation with very little precipitation has created this landmark, but it has taken since the end of the last Ice Age to reach its current state.

" Hard water is formed when water percolates through deposits of limestone and chalk which are largely made up of calcium and magnesium carbonates."
Wikipedia
The key words here being calcium and magnesium.

But as usual Meyers your reply made me think. Answer me this, if water hardness is simply the amount of salt dissolved in the water, what is the difference between General Hardness (GH) and Salinity, and why do they have two different scales for each?

You are correct though, that koi and goldfish can adapt to relatively hard or salty water, and my turtle might even prefer it, but everything I have read says koi prefer somewhat softer water than what I have, somewhere between 100 - 150 ppm. They are already putting up with the hard source water (180 ppm, or mg/L) that I have, I really don't want to make it any worse. The other thing is I also have frogs and minnows, and frogs (my type of frogs anyway) prefer much softer water, as is found in their natural habitat. So like anything it's a compromise. My source water is harder than I would prefer, I can't really change that, all I can do is try and keep it stable and doesn't get any worse, (with the key word being stable), and my trickle water change system works for that, plus it has the added benefit of maintaining a perfectly stable water level in the pond without the need to add water manually all the time.

As a side note, unlike natural lakes and streams and ponds that are generally flow through systems who's source water is continually fed by fresh soft rain water that maybe pick up some salts and minerals along the way, the source water in my pond comes from deep underground and is already heavily saturated with minerals (and salts), so I am already starting with a distinct disadvantage compared to most natural water bodies.

 

[sissy]

By the looks of all the rain we got water changes .I am testing the rain water just to see.They sent me a new test kit for free after I told them I think there was something wrong with the other test kit i got

 

[sissy]

this is ph from pond and rain water out of a stock tank that was empty and cleaned out before rain.I think you can see the difference one is more blue and one is green .The one on the left is the pond and right is tank .The tank has been empty for months and cleaned with peroxide and water and rinsed really well days before all this rain

 

[Meyer Jordan]

this is ph from pond and rain water out of a stock tank that was empty and cleaned out before rain.I think you can see the difference one is more blue and one is green .The one on the left is the pond and right is tank .The tank has been empty for months and cleaned with peroxide and water and rinsed really well days before all this rain

It is a well known fact that all rain water is acidic. Some geographical areas more than others.

 

[Meyer Jordan]

Randy, Total salinity in pond water is the sum of all of the mineral salts (ions) in solution. General Hardness is essentially the level of Calcium and Magnesium salts (ions) in solution. GH is a percentage of total salinity.

 

[crsublette]

It's not uncommon for me to loose 1/2" of water from my pond a day through evaporation and capillary action from the plants growing along the edge of the shore.. Although I've never allowed it to happen, it could take less then a couple weeks for the water to drop below the functioning level of my water skimmer and the pump to start sucking air. Plus I'm just sort of anal about the water level in my pond, I notice a 1/2" drop in the level with a quick glance.

@Mucky_Waters I have witnessed the exact same occurrence last Fall.

My little pond's water level was dropping about 2 inches every day. I was wondering... What the heck man? So I looked on the border of my pond...

Ends up, over time, dirt and debris built up in the rock on my stream's border that created a bridge for significant capillary (wicking) action. This capillary action was wicking so much water out of my stream that the outside ground beyond my stream actually became quite muddy.

I understood the capillary action, but I was floored by how much water was being wicked out of my pond.

I rebuilt my stream so that this "soil/debris capillary bridge" was tougher too occur by using different rock and not so much rock so that I can spray the soil/debris away from the border on occasion.

Since I have done this... I no longer lose up to 2 inches every day of water... I still have about a 1/8 inch water level drop every day due to a water leak in my pond that is somewhere, grrr, but at least it is water my trees that are next to my pond... So, I use a trickle of source water to solve this problem.