Automated Salt Water Mixing Station

[seldon]

I've been following the salt water mixing stations thread on here for a while now. I finally bit the bullet and started putting one together for myself.

I found some white 55 gallon drums on Craigslist for $10 a piece and bought 3. I plan on using two of them initially for the mixing station.

I also want my RODI filter nearby and to automate its water production. I mounted a couple 2x4s to the foundation wall I planned to put the station against. I had some extra sheets of Luan lying around and used it as a back panel to attach my equipment to.







I plumed 2 of the 55 gallon drums using 1.5” uniseals with 90° elbows turned down in each tank.



My external plumbing has a true union ball valve to a true union check valve coming out of each tank.



From there the tanks are joined with a 3-way pool valve.





I am then feeding a Waveline DC12000.

After that, I am only feeding one drum that I plan on mixing the salt in, but may set it up to be able to mix in either.

More to follow soon...

[slief]

Looks good. Hopefully that Haywood valve will hold up to the salt water in the mixing station. Most of those kinds of valves have metal parts in them and the stainless isn't necessarily a grade that is designed to hold up to salt water. I looked at an exploded diagram of that valve and some of the parts and I can't tell if there is metal in there or not. Anyhow, that would be my only concern.

[BigDave]

Originally Posted by slief

Looks good. Hopefully that Haywood valve will hold up to the salt water in the mixing station. Most of those kinds of valves have metal parts in them and the stainless isn't necessarily a grade that is designed to hold up to salt water. I looked at an exploded diagram of that valve and some of the parts and I can't tell if there is metal in there or not. Anyhow, that would be my only concern.

Not that I'm an expert, but they use those 3-way valves in salt-water pools. Granted the salinity is lower and I have no idea if they leach anything into the pool...

[seldon]

Originally Posted by slief

Looks good. Hopefully that Haywood valve will hold up to the salt water in the mixing station. Most of those kinds of valves have metal parts in them and the stainless isn't necessarily a grade that is designed to hold up to salt water. I looked at an exploded diagram of that valve and some of the parts and I can't tell if there is metal in there or not. Anyhow, that would be my only concern.

Fortunately there is no metal inside. It was something I checked when I got it.

[seldon]

Now on to the automation part. I’ll start with my RODI unit. I contemplated several ways of doing this and to be quite honest, I am still not certain if I'll change it up. At first, I considered a simple float valve in the tank with a pressure switch to turn the booster pump on. However, that wouldn't automate my flushing. I've seen the automatic flushing valves and considered them for a while, but for the moment my plan is to use a regular solenoid valve.

To control the RODI system I've been looking at using an arduino. To monitor the tank level I took inspiration from d0ughb0y’s thread:

http://reefcentral.com/forums/showthread.php?t=2328819

I had an arduino Uno lying around already and picked up an 8ch relay board and a pack of 5 HC-SR04’s. I hooked it all up on my breadboard and started testing the different components out on the extra 55 gal drum I have.



I wanted to put together an enclosure for the ultrasonic sensor. I picked up a 2” threaded to slip adapter, a 2” test plug, and a 2” cleanout adapter and plug.



Hopefully I can protect the electronics of the sensor a little better this way. The uno and relay board will be in another enclosure.

[muttley000]

Following this!

[dread240]

You know I have to say, especially in regards to rodi filling, I'm amazed at the efforts some people go through to do it.

Couple floats and a couple relays and you have 2-3 levels of redundancy for pennies. Been using the same systems on large diesel storage tanks pumping fuel to the roofs of buildings and what not where there are thousands upon thousands of dollars in fines if there is a failure.

[seldon]

Originally Posted by dread240

You know I have to say, especially in regards to rodi filling, I'm amazed at the efforts some people go through to do it.

Couple floats and a couple relays and you have 2-3 levels of redundancy for pennies. Been using the same systems on large diesel storage tanks pumping fuel to the roofs of buildings and what not where there are thousands upon thousands of dollars in fines if there is a failure.

Initially I started out that way. However, I have a knack for over complicating things... (speaking of knack, have you seen the Dilbert cartoon on that? https://www.youtube.com/watch?v=CmYDgncMhXw)


My end intent is not just to do RODI filling, hence the complexity. As I get into my code and some further explanation of the system as a whole, it should become clearer.

[seldon]

So below is the link to my github for the arduino code. This is essentially version 5 of the code and the first functional version.

https://github.com/seldon57/Automated-SW-Mixing-Station

I am working on version 6 which will clean up the code, add more comments and let certain constants be declared up top rather than fixed in the program (e.g. tank level limits). Additionally, I plan on making the code more modular so that I can more easily reuse some of the functions.

[wasmithee]

How did this work out for you?