What is the most reliable evap top off system

[BobinCovington]

I am adding my auto top off system to my sump. Any feedback on which is most reliable or least prone to problems??

I guess if you were to rank them in some order, what are your top choices and list any comments about them to help me make my decision.

 

[DonW]

Aqualifter and two float switches, if you plan on pumping out of a holding tank. Inexpensive and very reliable.

Don

 

[mattseattle]

I use the Tunze auto top off and it's awesome. Little pricey but very very reliable.

 

[Gimpster]

Are there any real draw back to a gravity fed vacum controled setup? You know a sealed resivor at or above the tank, one drip line from the botom of the resivor with a valve ending below the water surface, the other from the top of the resivor to the desired water level. The water level drops, air enters the top line letting water flow out the fill line until the top line becomes sumerged again and the system stops because of vacum seal.

Real cheap, only failure state is a loss of vacum in the resovoir, but if you set the valve to a limit the drip rate you can limit the speed at which the resivor empties. Works through power failure, can't be fouled or tricked by tank critters. Look like a good idea to me at least on small tanks.

 

[clayswim]

The drawback is just as you said, the loss of vacuum. Some people use them with great success; just don't try to mix kalk in them, you'll get it clogged.

The most reliable way to top-off? A jug of RO/DI water and your arms, but I don't think that's what you had in mind... I like float switches and a decent pump myself.

Clayton

 

[Blazer88]

I used someones schematic from RC that used a relay, 2 float switches, 12V adapter, and a pump. I think it cost me about $75 total and I'm happy with it. I can post the schematic and pictures if you are interested.

 

[NaH2O]

I use the Tunze auto top off and it's awesome. Little pricey but very very reliable.

Me, too. Love my Osmolator.

Blazer - post up the schematic you used and pics of yours if you could. That would be great!

 

[Blazer88]

Here is my auto top off setup. The two plugs in the back are for the 12V adapter and the float switches. I used the switches from floatswitches.net that were $6 each. The lower one maintains the water level and the top one is a backup. One thing I added that the schematic doesn't show is my on-off switch. I wanted to be able to easily turn the system on and off without having to unplug it. I used a 15 gallon container from Storables in Bellevue and ran the power plug and tubing through the wall from the closet. So far everything works like a charm. I can post a parts list from Radioshack if anyone is interested. Let me know if anyone has any questions about it.

 

[AcroSteve]

I use a dosing pump on a timer. It pulls from my 29 gal kalk container.

I prefer this to a top-off based on the water level in the sump because I skim rather wet. Using that method would result in the lowering of the salinity over time.

 

[DonW]

This is one thing Ive never understood with most diy dual float switch set-ups. Just like in the diagram above. DC voltage is much harder on a switch than a/c, also creates a much larger arc. If the first switch fails, most likely it will get stuck in the on position since its set up NO it will be on (pump running). You will never know that it has failed because the ATO will function just fine. Then you come home to a flood when the second one fails.

Don

 

[Blazer88]

How does this lower salinity over time? Freshwater evaporates and then is constantly being replenished as it evaporates. ATO with a timer seems like it would give you a salinity change and skimming wet since you are dumping more water from the tank in the form of skimmate. About the switches, I can tell if the first one fails since the water level would be higher and the first switch would be submerged. I've had faulty timers before; that seems more like an accident waiting to happen.

 

[DonW]

About the switches, I can tell if the first one fails since the water level would be higher and the first switch would be submerged. I've had faulty timers before; that seems more like an accident waiting to happen.

Since your running both the switches NO they both need to fall in order for the pump to operate. The water level would have to be very close to the same.
If they are going to fail wired with DC voltage the contacts are going to weld in the closed position (flood).
If they were just flipped to NC and the pump was fired with the other set of relay contacts this would be a much more reliable set-up. Complete the circuit with AC, break the circuit with DC.

Don

 

[Blazer88]

If the first switch fails and is stuck in the closed position, the pump will continue to pump until the water reaches the second switch, which then would be shut off. The top switch is always closed, or down, and isn't switching with the first switch. Does that make the switches NC? I mean, if a switch were to weld together it would be the first switch and not the second since the second doesn't operate unless the first one fails. Now I think I'm just confusing myself I didn't make that diagram, so I'm not sure if the wording is correct or not for the NO or NC. And is there any reason the switch would weld itself? The only current required would be to operate the relay which is 70ma, is that enough?

 

[AcroSteve]

How does this lower salinity over time?

I skim out about 3 gallons a week, sometimes more. I need to add this back as saltwater. If this was replaced with freshwater, you could see the effect fairly soon.

With my timer, I rarely have to adjust the salinity manually.

 

[aquariumdebacle]

The most reliable is you. Nothing beats adding the water yourself. The owner of Barr aquatics had a nice system with redundant failsafes. Maybe we could get Kevin to have him post his system. One of the few I would trust for a couple weeks.

 

[DonW]

I didn't make that diagram, so I'm not sure if the wording is correct or not for the NO or NC. And is there any reason the switch would weld itself? The only current required would be to operate the relay which is 70ma, is that enough?

Your switches are normaly open /NO. Yes 70ma will weld the contacts closed over time. This is why you can run so much more AC through a contact than DC. Look at the specs for your relay for example. It will be able to handle many times more AC than DC and the cycle life will be half of AC. That is why you run DC as a closed circuit so it will fail in the off position. I do think yours is very cool with the leds and switch, I'd just make it a normally complete curcuit.
These circuts came about when someone started claiming that a/c was dangerous while that same person has a AC heater and powerhead. They started poping up everywhere with no concern for how DC voltage effects contact life. The reallity is the best of both worlds would be to use a ac/ac transformer and run these off of 12 or 24v AC then you get true reliability and safety.

Don
Don

 

[Blazer88]

Interesting, I didn't think DC would have a negative effect on the switch. The relay I bought only states the coil rating in DC, so I'm not sure if it would work with 24VAC. And the website which I bought the switches from state they are NC, not NO. I'll see how long the switch lasts with the DC running throught the switch. If it doesn't last long I can order a 24 VAC relay and power supply to make a switch. Thanks for the information Don.

 

[WaterDogs]

I second the "The most reliable is you." The topoff system needs water added to it along with all the parts that malfunction, just add water to the tank and be done with it.

 

[DonW]

Interesting, I didn't think DC would have a negative effect on the switch. The relay I bought only states the coil rating in DC, so I'm not sure if it would work with 24VAC. And the website which I bought the switches from state they are NC, not NO. I'll see how long the switch lasts with the DC running throught the switch. If it doesn't last long I can order a 24 VAC relay and power supply to make a switch. Thanks for the information Don.

Its not the relay coil you need to be concerned with its the contacts in the reed. The relay in your diagram is dpdt meaning one set of contacts are no and the other are nc. The nc are the ones marked as unused. A 12v relay has a 12v coil and contacts are what is rated.
If you you are using the float to make the connection as in your diagram your are using the float as NO. The float switches are NO or NC depending on how they are used in the off state of the device that they are controlling. If you got them from floatswitches.net they are a either or switch that can be reversed by flipping the float.
Not comming down on your system just letting you know of a simple way to improve its longevity.

Don

 

[BobinCovington]

Don,
I looked at the JBJ system again for $99 and then the Ultrlife for $59. But you think the Aqualifter and two floatswitches is reliable enough? What floatswitch would you buy...floatswitches.net?