How to automatic mixing water

[sphelps]

Also so if anyone else is interested in another alternative to auto water change without a salinity probe you could setup something like this:

• Two separate top offs will be needed, one for fresh and one for salt.
• The fresh water top off is simply just your standard fresh water top off, set the float switch to trigger at your desired sump level. The only difference is you want the fresh water to be added slowly so use a small pump or restricted pressure/gravity feed.
• The saltwater top off will require a decent size storage tank where you can store premixed saltwater (the same salinity as the display). Install a separate float for the saltwater top off slightly lower than the fresh water float. Just low enough so the saltwater float isn’t triggered from evaporation.
• The saltwater top off should have a fast flow rate so use a decent sized pump.
• Next install another decent sized pump in the sump to remove water quickly for water changes. You can use a timer to activate it or just a switch if you prefer to keep more manual control over the system.

That’s pretty much it. The fresh water top off will replace evaporated water, the slower flow rate will keep up evaporation since this is a slow process. When the pump in the sump is activated to remove water it will do so quickly and activate the lower float switch which will trigger the salt top off. Since the fresh water flow rate is slow the fast saltwater flow rate will top off removed water before much fresh water is added. To make up for the small amount of extra fresh water added during a water change to can keep your salinity a little higher in your make up container. How much higher will depend on your setup and may require a little experimenting.

To limit the size of the container you need for saltwater storage you can try using saturated salt water. You will have to experiment but by placing the saltwater float lower in the sump you can control how much saturated solution is added in comparison to fresh water. You will however have to maintain a constant salinity in the make up container. You can either maintain a high salinity by measuring or you can maintain maximum saturation by keeping temperature consistent and always making sure some salt remains undissolved

[golf nut]

Originally Posted by sphelps

You will however have to maintain a constant salinity in the make up container. You can either maintain a high salinity by measuring or you can maintain maximum saturation by keeping temperature consistent and always making sure some salt remains undissolved

Curious as to why you leave some undissolved?

I agree that supersaturation is the solution to an economical top off design but a number of questions have been raised and it would be interesting to understand how many of the questions are valid, usually we mix batches of salt well ahead of when we do changes, some say this is needed to allow all chemicals to mix thoroughly,can we take a cup of salt, mix and serve immediately with no adverse effects?


Liquid handling isn't rocket science, I use proportionalizer valves every day and they work fine, precipitation is another issue in premixes as I am told, which could lead to other problems, removing a known amount daily and replacing the same volume appears to be less constructive as doing larger batches fewer times... true false?

speaking of liquid handling.......http://www.wimp.com/beerscup/

[mike31154]

Automation can be a good thing, but for mixing your salt water? Come on, such a simple task and we try to complicate it by coming up with some ingenious, but quite technical and work intensive/costly ideas. How long does it take to measure some salt, toss it into your mixing container and give it a stir or start up a powerhead? Augers, valves, proportionizers..... egad. The maintenance of all the extra gear sounds like more work to me than just doing it manually. Apologies if I sound a little negative here, not really my intent, just trying to present the simpler point of view.

[intarsiabox]

I just use the highly advanced method of drawing a line inside a bucket, filling the water to the line and writing on the outside of the bucket how much salt is required to bring that volume of water to the desired salinity. Works every time and takes about 30 seconds a week to make up my water change water. No extra cost or maintenance. Nothing at all wrong with mechanizing things but its up to the individual to determine if it is really saving any time or effort.

[golf nut]

Originally Posted by mike31154

Automation can be a good thing, but for mixing your salt water? Come on, such a simple task and we try to complicate it by coming up with some ingenious, but quite technical and work intensive/costly ideas. How long does it take to measure some salt, toss it into your mixing container and give it a stir or start up a powerhead? Augers, valves, proportionizers..... egad. The maintenance of all the extra gear sounds like more work to me than just doing it manually. Apologies if I sound a little negative here, not really my intent, just trying to present the simpler point of view.

Do you have a rotary phone?

[intarsiabox]

Originally Posted by golf nut

Do you have a rotary phone?

Seen one for sale lately?

[sphelps]

Originally Posted by mike31154

Automation can be a good thing, but for mixing your salt water? Come on, such a simple task and we try to complicate it by coming up with some ingenious, but quite technical and work intensive/costly ideas. How long does it take to measure some salt, toss it into your mixing container and give it a stir or start up a powerhead? Augers, valves, proportionizers..... egad. The maintenance of all the extra gear sounds like more work to me than just doing it manually. Apologies if I sound a little negative here, not really my intent, just trying to present the simpler point of view.

Takes even less effort to top off your tank with fresh water compared to changing actual saltwater but most would agree a standard ATO is a must have these days. Not only to make your life easier but to promote stability. AWC is a very simple concept with a programmable controller with salinity measurement and employing a such a system is just another way to promote stability and free your time for more important things like actually enjoying your tank. If you enjoy manually mixing and changing water that's cool but most would agree it can sometimes be a hassle and often gets neglected.

[sphelps]

Originally Posted by golf nut

Curious as to why you leave some undissolved?

I agree that supersaturation is the solution to an economical top off design but a number of questions have been raised and it would be interesting to understand how many of the questions are valid, usually we mix batches of salt well ahead of when we do changes, some say this is needed to allow all chemicals to mix thoroughly,can we take a cup of salt, mix and serve immediately with no adverse effects?


Liquid handling isn't rocket science, I use proportionalizer valves every day and they work fine, precipitation is another issue in premixes as I am told, which could lead to other problems, removing a known amount daily and replacing the same volume appears to be less constructive as doing larger batches fewer times... true false?

speaking of liquid handling.......http://www.wimp.com/beerscup/

Ensuring some salt always remains undissolved insures the salt solution is at max saturation and with constant temperature you can be sure the the salinity of the make up is consistent (max saturation at given temp). You could also in theory measure the salinity and keep it constant however it can be difficult to measure salinity of saturated saltwater and it's easier to just simply look for undissolved salt. It makes other options easier to employ as well. This is of course only important without the use of controllers, a controller eliminates the need to maintain constant salinity in make up water.

Some salts seem to require longer mixing times but I've used many salts that mix clear almost immediately and I've added cups of salt directly to sumps many times while preforming water changes without any adverse effects. Other peoples results may vary but I've never really pre-mixed saltwater ahead more than a few hours or so, typically I mix new water at the same time as I'm removing old water.

In the automated systems I've used and setup in the past I've always put importance on the less more often approach for stability. The systems would usually change a smaller percentage daily rather than a larger amount weekly or even monthly. This could very well be an important part of the systems I've previously described.

[wolf_bluejay]

Originally Posted by sphelps

Ensuring some salt always remains undissolved insures the salt solution is at max saturation and with constant temperature you can be sure the the salinity of the make up is consistent (max saturation at given temp). You could also in theory measure the salinity and keep it constant however it can be difficult to measure salinity of saturated saltwater and it's easier to just simply look for undissolved salt. It makes other options easier to employ as well. This is of course only important without the use of controllers, a controller eliminates the need to maintain constant salinity in make up water.

The chemist in me really really cringed at this. Saturating the salt water mix is bad idea.
This would work IF we were only using one salt, but the mix is just that, a mix. All the different chemicals that make up our fairly expensive salt do not saturate at the same levels.
This saturation is used sometimes to purify (removed unwanted salts) in many production chemicals. The NaCl would be almost the highest solubility. So you end up with just mostly NaCl and almost all the calcium and trace minerals would be what would precipitate out of solution.


Think of it this way -- if you dumped a whole lot of salt mix and pushed it to saturation, separated the precipitate out, add more salt mix and repeat -- you would have some expensive NaCl without much else in it.

[golf nut]

Originally Posted by wolf_bluejay

The chemist in me really really cringed at this. Saturating the salt water mix is bad idea.
This would work IF we were only using one salt, but the mix is just that, a mix. All the different chemicals that make up our fairly expensive salt do not saturate at the same levels.
This saturation is used sometimes to purify (removed unwanted salts) in many production chemicals. The NaCl would be almost the highest solubility. So you end up with just mostly NaCl and almost all the calcium and trace minerals would be what would precipitate out of solution.

So how would you make a good solution that could be handled ?