DIY Auto-Top off with Solenoid

That's a great write-up, and definitely more failure-proof than the above. However I would like to see the statistical analysis that determines how "much" safer it is. I guess we would have to know the MTBF of the floats and the solenoids in the reef environment to calculate that though.

Can you tell us which solenoids you are using?

Zeph
 
Zeph,

It's not my site. The designer is a prof. at Georgia Tech. I've asked him about a few things over the past couple of years
and have found him very amenable to answering questions. I don't know the background behind the 'quad-logic' stuff :confused:, but I trust that he does and hope to emulate his system. The acrylic float switches he uses are pretty darn cool but beyond my fabrication abilities.

The rest of his site is well worth reading for ideas.......

A few months back I happen to be listening to NPR news and got a chuckle when they interviewed him regarding some NASA-related news story.
 
Zeph, so have we determined that the solenoid is a good one for our purposes or have you found something better? Also can I put this solenoid on a timer so that it only runs during certain times?
 
I've not found a better one, but I have not looked either.

Running it on a timer should be great. I don't because mine runs though a kalk reactor, and I would rather dose kalk all day instead of in a batch (when the timer kicks on.)

Zeph
 
(hope you don't mind if I barge in on this thread and post a few pics)

I built a float switch close to a year ago which drives a small pump located in a bucket of DI water. I had problems with the reed switch "sticking" after about 6 months of use. I'm using a Madison switch and after talking to them decided it was due to high inductive start-up currents. A general solution to this problem can be found on their website here: http://www.madisonco.com/reference/floatswtech.htm. My solution was similar only I also reduced the current through the switch by using a triac. Here's a schematic of my fix:

schematic.JPG



Here's a picture of the assembled circuit:

circuit.jpg


And here's the end product. All the electronics fit nicely into a small piece of 3/4" pvc pipe:

switchmod.jpg


No problems now and I can run any motor up to 4 amps!
 
You can also reduce current thru your float switch by using a relay. Same concept. See various posts in this thread for schematics.
 
You can also reduce current thru your float switch by using a relay.

Yes, that was what I orginally planned to do, only I wanted to keep it all as small as possible. And I couldn't find a relay small enough to fit the bill. As you can see in the picture, the triac is very small (and is in essence a relay/switch). Maybe I just didn't look hard enough... are there small (AC) relays?
 
This is a great thread, I have just purchased my solenoid.

Zeph - Did you post that you have a small surge?

Im setting this up on my new tank that will have a 40gallon surge and a 160 gallon sump, but the water level is stil going to rise and fall in the sump along with the surge.

I wanted to know how is yours working with the flux in the sump? Does it just come on every time the surge is about to go?

thanks
 
platapus said:
Zeph - Did you post that you have a small surge?
Click to expand...


Exactly. As the sump level falls, the float switch trips and dribbles in a little water. The surge hits and the float turns off. This means the float switch cycles pretty often, but it never stays "on" for long either. My "surge" is about 1/2 to 3/4" (3-4 gallons).

I have been considering putting the solenoid on a timer so that it can't be "on" except for 15 minutes every hour or less. The draw back there is that I dose Kalk, and would rather the top-off trickle in over a large period.

1/4" speed-fit to 1/8" NPT is what you need, it looks like #58151 on that page (two needed of course).

Zeph
 
Thanks - Ill order them.

Is there any reason why I cant use a Ultra-Life float switch instead of the one that you used from mcmaster.com? Mainly because I have had an untralife switch for about a year and never used it.


thanks
 
platapus said:
Thanks - Ill order them.

Is there any reason why I cant use a Ultra-Life float switch instead of the one that you used from mcmaster.com? Mainly because I have had an untralife switch for about a year and never used it.


thanks
Click to expand...

I have mine hooked up with an Ultra-Life Float as well! Works just the same, just less wiring.
 
Recently I've noticed that there are better float switches around than the one I used. Due to the design of the float, it more prone to having a small snail jam it closed, then other designs.

I suggest looking for a design that looks more like type "D" on the McMaster page 447. (mine is a type "A".)

The "D" type looks to not have the pinch-point that can capture a snail.

Zeph
 
I got my solenoid.....Is this the right one?

Also - this one has a "IN" stamped on it, I remember some people saying they were hooking them up backwards?

<img src=http://bluechunks.net/reef/225reef/plans/solenoid.jpg>
 
Looks good to me- Yep, there is a backwards. I did not notice an IN on mine, I'll check tonight though.

Zeph
 
Platapus, hows the flow through that little solenoid? Isnt it only 1/8"FPT?
THX
Chris
 
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