How to automatic mixing water

[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.

[donlite]

What I have set at this point is very simple. I have 2- 30 Gallon drums (coke sells used drums for about $20). One is filled with fresh water and is connected to a float switch in my sump. The other tank has saltwater in it. I use one water lifting pump for the top off and 2 pumps for the water change. The water change pumps turn on and off together throughout the day. The problem is that the 2 pumps must have the same flow rate. I checked them and they are almost the same. I also have a second float switch that turns all the pumps off if something stays on or off. It is not a perfect system but it seems to work.

[sphelps]

Originally Posted by donlite

What I have set at this point is very simple. I have 2- 30 Gallon drums (coke sells used drums for about $20). One is filled with fresh water and is connected to a float switch in my sump. The other tank has saltwater in it. I use one water lifting pump for the top off and 2 pumps for the water change. The water change pumps turn on and off together throughout the day. The problem is that the 2 pumps must have the same flow rate. I checked them and they are almost the same. I also have a second float switch that turns all the pumps off if something stays on or off. It is not a perfect system but it seems to work.

Yeap a very common method and works well for many people. With almost any system you'll still need to check salinity and make adjustments. Even systems with conductivity probes I still found the calibration/set points required slight adjustment every few weeks.

Rather than matching two pumps I find the use of float switches to remove and replace a consistent amount of water takes a lot of the guess work out.

[golf nut]

Originally Posted by sphelps

Rather than matching two pumps I find the use of float switches to remove and replace a consistent amount of water takes a lot of the guess work out.

Would a double stage cylinder be a better choice if it could be produced inexpensively?what volume would you need to move?

[sphelps]

Originally Posted by golf nut

Would a double stage cylinder be a better choice if it could be produced inexpensively?what volume would you need to move?

Not sure what you mean, can you explain? There is of course is a ton of different methods to remove and replace a consistent amount of water, I just mentioned one that I've used before.