How to automatic mixing water

[Coleus]

Well, i am thinking of a process to mixing my fresh salt water automatically so i can have auto waterchange.

I have salinity probe, float switch and outlet controls so i can turn on and off outlet when it meet the salinity. My only puzzle is how i can find some kind of rotating drum (just like a fish feeder), that can slowly pour the salt into the water bucket until it reach the salinity level. Anyone know one that is bigger enough to do the job?

[hillegom]

you might also think of something with an auger, like the pellet stoves use. However, it would have to be made all out of plastic.

[michika]

Auger seems to be the best option, and I can tell you because I've spent two years now looking at and for really well done automatic water change systems. There aren't a lot out there yet.

If you want some other ideas there have been people who have automated the process using their Reef Keeper controller on the Digitial Aquatics forum. Even if you don't have an RKE, some of the styles and problem solving techniques might be worth it for you.

*Edit* While I was looking for something else this thread on RC popped up about different mixing stations. I know they aren't all automated or anything, but it might give you some more ideas. Salt Water Mixing Stations Let's See Them

[Cranky When Wet]

Rotating drums immediately brings to my bunny mind a Lapidary tool.

Lapidary is the art of cutting rough rock into gem stones. Normally, rotating/grinding machines are used for the process.

A less-formal method involves using various sizes of rotating, plastic-lined, drums for polishing rock.... it's a good method for teaching kids how to polish semi-precious gems since the machines are much safer.

Drums can range from one pound capacity to any size you want (i.e. 10, 20, and commercial sizes beyond that).

The trick will be to automate how the salt is dispersed.

I suggest speaking with the Calgary Rock and Lapidary Club. They could direct you to people who could help you see these units in operation and even to buy a machine if someone is no longer using theirs... Here's the link: http://www.crlc.ca/index.htm

Hope this helps and will look forward to hearing your success :-)

Bunny

[Lampshade]

The issue with drums is finding a food safe drum so that the Bearings aren't exposed to the salt, and also made of stainless. Anything else would be pretty scary to use on the tank :S.

My opinion would be a simple hopper with a valve. You need something that will seal off the salt when not in use, if it's in the same area as mixing water, the humidity will make it a salt block in no time. If you made a desenct sized hopper with a small outlet, even a 0.5" opening you could open/close that to add salt. Program it so that the hopper is open for a short period then closed for 20+ seconds to allow the salt to mix. Make it cycle whilever your salinity is low.

[Cranky When Wet]

All very valid points...

With that in mind, Lapidary tumbler drums are typically isolated from bearings... I wish I could comment on the grade of the poly/vinyl liners but I've never tested the units for SW applications.

There are a number of manufacturers worth speaking with i.e. Thumlers, Covington or Lortone (just don't look at the cheap units - they are trash and don't last.)

Covington does make a "Hopper-type" unit for polishing gold/silver castings... Here's a link to see what they look like...
http://www.covington-engineering.com/deluxe_tumblers.htm

One might look at their "Vibratory" Tumblers as well? Tho I'd be concerned about heavier elements sinking to bottom and causing tank troubles... http://www.covington-engineering.com/vibrating_tumbler.htm

I'd personally lean towards Covington for getting answers to technical questions...

I do like your thoughts on using a hopper sporadically :-)

Bunny

Originally Posted by Lampshade

The issue with drums is finding a food safe drum so that the Bearings aren't exposed to the salt, and also made of stainless. Anything else would be pretty scary to use on the tank :S.

My opinion would be a simple hopper with a valve. You need something that will seal off the salt when not in use, if it's in the same area as mixing water, the humidity will make it a salt block in no time. If you made a desenct sized hopper with a small outlet, even a 0.5" opening you could open/close that to add salt. Program it so that the hopper is open for a short period then closed for 20+ seconds to allow the salt to mix. Make it cycle whilever your salinity is low.

[sphelps]

Super saturation is your answer. Setup another water top off using something like a 29 gallon aquarium. Drill and install an overflow in the aquarium and mount the aquarium above sump level. From your fresh water top off use another pump or solenoid depending how it is setup. Send one fresh water line directly to the sump (Fresh top off). Send the other fresh water line to the 29 gallon aquarium (salt water top off). Plumb the overflow into the sump so when fresh water is added to the 29 gallon it overflows and drains into the sump. Next fill the 29 gallon with water and add a full bucket of salt, use a small powerhead to keep the water circulating and even a heater if you wish. Now setup your controller to either activate the fresh water or saltwater top off based on the salinity measurement in the sump. The salt water added will be supersaturated but it won’t matter as the controller will simply cut it off once salinity is restored in the sump. This will maintain salinity so to auto change water simply hock up a pump and timer in your sump to pump water to a drain. Depending on the controller you can even set an alarm for low salinity which will prevent the pump from removing water so it won’t change water if salt is needed. And when salt is needed simply add another bucket to the tank, doesn’t get any easier. Done this exact system with a profilux before, it was dope!

[russp]

I may have an idea for you , I own a convenience store & I have a hot chocolate machine that has a food grade plastic hopper with a plastic auger in the bottom . It is driven from the back by an electiric motor & coupler system. the hopper would probably hold about 2-3 lbs of salt at a time . I will try to post a picture for you if interested.

[Bloodasp]

Problem with supersaturated solution idea is the amount of maintenance you have to do to the ATO pump. As It doesn't run continously so if the water evaporates your ATO will eventually clog with salt pretty fast since it is supersaturated.
I'd go with the auger idea, just what type of material it should be made of would be the issue, plastic wouldn't work as the salt would act like a sandpaper and would wear the auger out in no time.

[Bloodasp]

Though I wonder if an auger made out of PVC material would work.