DIY Auto-Top off with Solenoid

[Roland Jacques]

<a href=showthread.php?s=&postid=7307276#post7307276 target=_blank>Originally posted</a> by Zephrant
Very nice- Thanks for sharing that.

Please post the part numbers if you get a chance- Nice to have "tested" parts to use.

Zeph

Dito on the parts list. looks good

i just came from one of my favorite 300 gallon reef tank that had fish dieing. when i got there i noticed no life. i could not figure out what was going on then i looked at the skimmer saw no small bubbles. Ouch, it had turned from a tank that was on it way to being awesome, into a 300 freshwater reef tank i still feel sick about this. the mechcanal kent top off valve stuck open. i dont no how many days it took to get a 300 gallon tank down to 3% salt. (what i normaly keep my FW fish at) im try to figure out how long that valve must have been stuck open but it really does not matter. i saw 3 fish still alive. i hope thiers more hiding.

all that to say, if your thinking about this. Just Do It!

 

[BeanAnimal]

A ferw notes:

The air pressure switches are great. The only concern is that some of them do have metal parts that will be on contact with "salt air" if the open end is dipped into the sump. More than likely not a bif deal... just something to keep an eye on.

With any auto-top system it is a very good idea to build in fail safes. The simplest is a "high water" float in series with the solenoid power (or float switch that actualtes the solenoid). However this does nothing to help you if the solenoid sticks open.

I would recomend that that sump be fed via a Kent or similar float valve, placed at a level above the normal operating level. You can still use your float switch setup, and rely on the mechanical float valve as a saety shut-off. Used in conjuction with the safety float, this is a fairly safe system to operate and covers most common failures.

For those with a little bit of extra space and a few extra bucks... Your imagination is the limit. I fill a 7 gallon bucket with my top-off system. The bucket in turn fills the sump with a similar top-off system and gravity. Worst case scenario no matter how many pieces of equipment fail, I only put 5 gallons max of fresh water into my sump (unless ALL of the equipment fails).

We had a small (10-20 gallons) top-off flood when I first set the system up (good ol manual way) and neglected to turn the valve off. If it happens again I will be asking one of you for a couch to sleep on.... therefore I designed a system so that it could never happen again.

Bean

 

[douggiestyle]

ive noticed some posts in this thread searching for valves.
i apologize i cannot locate the site but someone may wish to do the search. nc or no 1/4" SOLENOID PINCH VALVES. found them for about $30. pressure rating was high enough etc. perfect for those concerned with brass etc. coming in contact with ro/di water. if i locate i will reply but dont hold your breath. try searching for them.

 

[BeanAnimal]

I have not been able to find pinch vales with a suitable pressure rating. Most I have found are about 30 PSI max. Anything that is suitable in size has turned out to be over $100.

 

[douggiestyle]

<a href=showthread.php?s=&postid=7309898#post7309898 target=_blank>Originally posted</a> by BeanAnimal
I have not been able to find pinch vales with a suitable pressure rating. Most I have found are about 30 PSI max. Anything that is suitable in size has turned out to be over $100.

i cannot find them either. but i know they are out there. stumbled accross them looking for something else. swore i stuck the site into favorites. im still looking

 

[thereefgeek]

<a href=showthread.php?s=&postid=7307276#post7307276 target=_blank>Originally posted</a> by Zephrant
Very nice- Thanks for sharing that.

Please post the part numbers if you get a chance- Nice to have "tested" parts to use.

Zeph

Here's where I got the switches. Remove the adjustment screw and it will switch with the lowest amount of presure (3/4" of water in my case) :

http://www.herbach.com/Merchant2/me...AR&Product_Code=TM96SWH2938&Category_Code=SWH

I got the water solenoid from http://www.mcmaster.com/ Catalog page # 420, Part # 7877K2, 120vac, 150p.s.i. Polypropeline/Buna seals & male spade terminals.

The box and lamps are from Nerd Hut (Radio Shack). You can see in an earlier version I built for a friend (to switch a powerhead) the red and green neon indicator lamps- Red=Power on, Green= Pump (or Solenoid in my case).

The sensor tube is just a length of Poly sprinkler riser pipe from Home Depot (in the irrigation section) and the vinyl tube is across the isle (1/8" I.D.) and fits perfecly inside the John Guest (1/8" tube X 3/8"NPT) quick fitting on top of the black Poly.

I used teflon tape and teflon Pipe dope on the JG threads when I screwed it into the poly. This connection MUST be air-tight or the switch won't hold pressure and you'll flood your sump!

To hold the black sensor tube at the right level in the sump I just used a cheapo suction cup heater bracket from PetSmart ($0.99)

All the black tube does is trap an air bubble and hold pressure against the switch (normally closed), keeping the circuit open. When the level in the sump drops a bit, the switch closes, turning on the solenoid (and the green lamp) adding enough freshwater to raise the level in the sump back up to where it's supposed to be. When the level rises, the air bubble turns off the air switch (and the green lamp) and the solenoid closes.

3/4" +/- in my sump equals about 2.75 quarts and my salinity barely fluctuates between the high and low settings. This thing works like a charm :smokin:

 

[thereefgeek]

I should add that the whole thing was less than $50 to make.

 

[Zephrant]

That's great all- Thanks for posting that.

The Kent float valve as a backup is great Bean- That is what I'm currently using, and it is pretty foolproof. The only downside is I suspect it might clog if used with Kalk.

Zeph

 

[melev]

Hey Zephrant, aren't you missing a few thousand posts?

I agree with BeanAnimal about limiting your possible issues, and never have more than 20g of RO/DI water in the resevoir. Even if every drop is added, my reef will be unfazed, and that is a good thing.

 

[BeanAnimal]

Yeah some folks have reported that the kalk can be an issue. I don't dose Kalk, so therefore have no first hand experience. I would much rather clean a bit of calcification once in a while than risk a flood though.

Having an unlimeted suplly of fresh watet to a reef system is always a big risk, anything we can do to minimize the that risk is a large step in teh right direction. Top-off and heater malfunction likely acount for most of the preventable tank crashes.

 

[douggiestyle]

i recomend at least a back up float switch for the solenoid. one mounted higher in case the lower one fails. i speak from experience

the float valve is a prob if using lime water. but it might work when needed. an "in case of emegency" thing. better than having nothing.

still looking for that pinch valve. maybe i had to much to drink that night and imagined the whole thing, lol. also am searching for isolated valves. i do this for not for me because i do not believe that having some brass in contact with ro/di water is not going to contribute any measurable amounts of copper etc to the tank

 

[melev]

Doug, brass will cause harm, guaranteed. We've had a couple of tanks simply implode in the club in the past 12 months, both related to a brass fitting. Now if the fitting can be replaced with plastic, that would be ideal.

 

[douggiestyle]

brass fitting in the tank? or on an ro/di line?

ive had some brass fitting on my ro/di line going on 4 years. and no problems.

would agree that plastic would be ideal.

 

[BeanAnimal]

Hayward makes a suitable ALL PLASTIC isolated solenoid valve. Last I checked it was around $140. I contacted them a few times to negotiate a sample or special interest buy, and was told to eat my hat. Hayward is not a "manufacturer" anymore, they are just a company in a chain of companies, they really don't even know or understand what they make or attach their name to. and could care less about anything less than a contract that is in the 6 figure or more range.

http://www.haywardindustrial.com/html/prods/prod.asp?TLDID=2&ProdID=50

The valve type is commonly called NPD (non pressure differential) and in this case hayward has sealed the shading coil and other wetted parts. This valve is truley reef safe (at least from what the specs say). It jost costs a lot. It should also be noted that just because the literature says something, does not mean that you can count on it. If you recall, most of the solenoid valves listed as "no wetted metal parts" actually have wetted copper shading coils. Not good.

The PINCH valves that I have found to be suitable are a product from ASCO. However they come from the scientific division and do not appear on the ASCO website, but rahter the asco scientific website.

I hope some of this information helps. In the mean time I guess we will all continue to use the copper shaded valves.

Bean

 

[douggiestyle]

yeah found those asco valves.

anyone check on the ss valves $32 apx.

 

[festus]

If the solenoid ever fails open (unlikely, as it is a normally closed valve) the float switch will prevent the sump from getting too much fresh water.

I've seen such solonoids fail. Usually from hard water deposits that prevent it from sealing properly even though they are closing.

But your second float would stop a flood. And then when the water bill came I'd be sure to notice the solonoid was leaking ;-)

Looks great I may just try to implement this rather than some other rube goldberg like device I was ginning up on my own.

Thanks.

 

[douggiestyle]

<a href=showthread.php?s=&postid=7315493#post7315493 target=_blank>Originally posted</a> by festus
I've seen such solonoids fail. Usually from hard water deposits that prevent it from sealing properly even though they are closing.

agreed but... hardwater deposits will be HARD to come by with ro/di water.

pun intended

 

[H20ENG]

Dont buy those switches from Herbach!!! They are not the correct range and do not have any adjusting screw.

"Operates on 0.5 PSI (Ã"šÃ‚±5%) coupled to a SPDT Microswitch with contact rating of 20 Amps "

A good giveaway is the 20A switch rather than the 3A switch. I bought and returned 10 of them from Herbach and it took 2 months for my refund.

This has been the biggest problem with building the air switch setups- finding a good supply of switches.

That said, Rich made a kick butt setup there

 

[thereefgeek]

Thanks, H2OENG!

I just pulled the Herbach link outa' my butt, surfing for air pressure switches.

The Micro Pneumatic Logic switch part # that I used is a 601 series http://www.pressureswitch.com/fs_int/multi1.htm

Aquatic Eco Systems http://www.aquaticeco.com/index.cfm/fuseaction/product.detail/iid/1101/cid/2249 sells them, but they're something like $25!!!!

I picked mine up from a local electronics surplus house in Sacramento for $5 each and bought all that they had
Keep your eyes opoen for the deals, or pony up the $25 for an ultra reliable top-off switch.

You could always buy the Spectrapure unit, but then it wouldn't be a DIY

 

[BeanAnimal]

I gave chris a link a while back to some decent switches.... I will look and see if I can find it.