Is it possible to recycle salt from water change?

[bklynmet]

Just was wondering if it is possible to recycle the salt from the water extracted from the tank during a water change. I'm thinking running the extracted water through activated carbon for a day to 'clean it' then set out in evaporation tubs so the water evaporates and your left with salt.

Is the feasible? Anyone try it? Any reasons why not to do it?

[daddypugg]

hhhmmm intersting thought! I will tag along and watch the opinions on this one.

My first reaction was the time invested would not yield enough salt to really make it worth while but ya never know.

[Reefugee]

There are two problems I see with this:

1. When you evaporate the old salt water, some of the stuff you are trying to remove will also dry up with the salt. So when you rehydrate it, it will be in the salt.

2. The original salt mix contained some elements that may have been used up by the corals. You will have to try to add those elements/compounds back in.

In my opinion - not worth it.

Minh

[leoskee]

Im not sure you can with the concentration of salt we have in our water. Salt flats contain high levels of desolved salt in the water. This is sometimes achieved by concentrating the water as it evaporates so that the salt content builds up.

I guess you could do it if you have a 500gl plus tank and did 100% water changes. But even then you would only get a small amount of salt back in a crystalized form.

[albinooscar]

Why would you want to do that? One of the biggest reasons to do a water change is to replenish the elements in the salt mix that were used by the coral and other critters in the aquarium.

Ron

[leoskee]

Thats pretty simple AlbinoOscar. I totally agree with you.

[Barry L]

It might be interesting to have the salt checked by a chemist, to see exactly what elements were used and in what proportions. Also what is in the salt now that wasn"t in it before! (maybe from the food? )

[albinooscar]

<a href=showthread.php?s=&postid=7262333#post7262333 target=_blank>Originally posted</a> by leoskee
Thats pretty simple AlbinoOscar. I totally agree with you.
Thank you.

Another thing to keep in mind is that all the different kinds of salt mixes we use are man made.

If I were you I would just fa-getta-bout it. As previously state, to much time and energy for to little re-claimed salt.

[Qwiv]

No, you can't.

First, when the water evaporates the salt will form crystals that will not disolve correctly when you add more water later. Same reason you are not to push salt creep back into your tank.

2nd. All the waste you are trying to remove will be left in the solids. When you add water again, you put it all back in the tank. Putting GAC in the removed salt water will not work for this. If it did, you might as well throw the GAC in the aquarium and save doing the water change.

3rd. New salt water also replaces substances used by your corals. I guess you can rely 100% on supliments, but the test kits, suppliments, time and the fact we can't test for everything would make that pointless.

4th. If you cannot afford salt water, but have time and space to evaporate salt water in qty, you need a job or are in the wrong hobby.

[sunfishh]

I think you are looking at the wrong solution. I remember reading once a long time ago that Martin Moe would sometimes use bleach to destroy dissolved organics in his water. He said it worked well, but of course it did not destroy nitrate :(

[goby1]

If it were easier to remove the unwanted stuff from solid form, it might be a good idea. The process of hydrating an artificial mix, and then dehydrating it, is an irreversible process. The rehydrated residue will not be of the same composition molecularly as the original solution. I believe the problem is with the buffers. If you are or have a friend in chemical engineering, they might be able to advise on the processes available to separate the components. It certainly can be done. My guess is that many of the ingredients in asw come from the ocean to begin with, because the elements are available in the correct ratios, and it's readily available. If you could at least pull off the NaCl, there are mixes available that contain everything but the NaCl. Cheaper shipping...

Pollutant wise, there shouldn't be anything bad in the residue other than nitrogen and phosphorous compounds, the identity of which I don't know.

Even if it cost more, mixing your own asw is more or less unprecidented on rc, and would merit a good thread and lots of laughs...

Ask Randy.

G1

[thereefgeek]

<a href=showthread.php?s=&postid=7261844#post7261844 target=_blank>Originally posted</a> by bklynmet
Any reasons why not to do it?

Because salt is cheap and it's a good excuse to do a water change. You could however scrape the dusty, disgusting salt creep from the sides of the tank and use that for your water changes ;)

[dalbrecht]

It won't work for a simple reason. Salt water is made from a variety of compounds. Each of these compounds precipitates out of solution in a heterogenous fashion, Sodium before magnesium before iron etc...

If you were to try to fully dry the waste water in your tank, you would wind up with a layered cake of precipitates that will not readily re-disolve.

[bklynmet]

<a href=showthread.php?s=&postid=7265860#post7265860 target=_blank>Originally posted</a> by dalbrecht
If you were to try to fully dry the waste water in your tank, you would wind up with a layered cake of precipitates that will not readily re-disolve.

Simple enough reason why not to do it and makes perfect sense. Also the response regarding phosphate and nitrate removal is a very good point as you wouldn't want this reintroduced.

I don't understand the comments from some of you that indicated reintroducing salt creep is not good because it will not redissolve due to it's crystalline form. IME it always redissolves - just don't get it on corals. Let me state this before there are more negative posts - I do not intentionally reintroduce salt creep but sometimes dislodge some when scraping the glass.

wow.. you start a thread just a conversation piece and you get some pretty hostile responses from some RC members.

so is all the salt in the aquarium trade totally "engineered"? or is it processed from the saltwater mother nature gives us? It would be cool if there was a simple DIY method to get the salt back up to snuff because paying $40-50 for a bucket of every few months does add up.

[sunfishh]

wow.. you start a thread just a conversation piece and you get some pretty hostile responses from some RC members.
I hope I was not being hostile. I was just putting in my 2 cents. Please take it with a grain of salt (store bought or recycled) :)

[Reefugee]

Hostile? Who is being hostile? I think people are giving you their opinion.

BTW - I don't understand the comment about salt in "crystalized" form not dissolving correct. Also - no sure about the comment about hydrating and dehydrating or the layer comment. They don't make sense to me.

<a href=showthread.php?s=&postid=7266165#post7266165 target=_blank>Originally posted</a> by bklynmet

wow.. you start a thread just a conversation piece and you get some pretty hostile responses from some RC members.

[douggiestyle]

there is a system that does water changes and reuses the salt,
it uses a r/o membrane. the nitrates and phosphates slip through the membrane and the salt stays behind. unfortunatly other things slip through. this requires some fancy technology to ballance out. but essentialy it is constantly doing a water change on your tank. start up cost is high. if i find it i will post a link.

your idea is a good one. perhaps that is where reef keeping is headed in the future.

[goby1]

All the compounds that are involved are crystalline in their solid form.

As I would think about it, scraping the crust back in is only bad if the solid lands on corals before it redissolves, or if it has accumulated other stuff like dust over a long period of time.

If the layered cake theory is true, then maybe that is one way to go about it. I would guess that carbonate would be the form that calcium and magnesium come out as, both of which have low solubilities in water. Once you have the elements separated into oxides, hydroxides, carbonate forms, etc., the rest is energy, equipment, and some research. Getting to this point seems to be the tricky part, including the fate of organics. After figuring out one way to do it, you'd have to consider the money for equipment, money for electricity, and time.

I'd bet there is a way that is feasible, either discovered yet or not, that would be something that some of us would want to do.

Thinking about it another way, what is the point of water changes? To refresh/remove the ions/toxic organic molecules that we don't test for? Along this line, it might be better to confront the impurities/replenishments while the main phase is liquid.

Yeah I don't think anyone was being hostile either. Maybe they accidentally posted that to the wrong thread?

[goby1]

Nevermind, the post is in the middle of other comments...

G1

[BeanAnimal]

The point is that when you evaporate salt water, the concentrations of certain elements become very high. These high concentrations cause precipitation. You end up with different compounds than you started with. Some of these compounds (like calcium carbonate to name one of many) do not redisolve. It's that simple.

You simply don't get what you started with when you disolved the salt in the first place. Yes all that atoms are there, but many have combined to form new substances due to the high concentrations that occur during evaporation.

Bean

[goda]

maybe if you distill it you could get a fraction of the salts back

[douggiestyle]

http://www.reefkeeping.com/issues/2006-04/pr/index.php

here tis

salt water recycling

[goda]

not really . that is dialisis you still need to make new SW and it just is like some wierd ion exchangy thingy.

[douggiestyle]

well that is what dialyseas is. take take out the bad and leave the salt behind. recycling the salt.

i think it would be easier and more affordable to do a continuous water change. mix 55gal of saltwater and remove and replace at the same rate. say 2 gal per day, would last nearly a month.

[douggiestyle]

<a href=showthread.php?s=&postid=7274147#post7274147 target=_blank>Originally posted</a> by douggiestyle
well that is what dialyseas is. take take out the bad and leave the salt behind. recycling the salt.


you may be rightafter reading the review (which is horrible) i have yet to determine what exactly this thing is doing. come on give a synopsis on all its operations (how and why) first, then get into the nitty gritty. my first impression was that it is like a r/o filter only removing the small bad things. he mentions removing Cl and removing Na but no mention on removing NaCl??

But im soooo impressed..:rolleyes:

then again maybe im just not smart enough, and ill be the first to admitt it.