Auto Top off question??

scottwhitson · 01/25/2007, 12:08 AM

I have been looking at a lot of auto top off systems and see that everyone is using 12Volt relays and 9 volt batteries to run them. Why couldn't you or why don't you use a 120 Volt relay and just wire it to use a regular plug in?? I don't understand the point of the 12volt relay system.

Dubbin1 · 01/25/2007, 02:15 AM

One reason would be for a power outage.

TekCat · 01/25/2007, 03:06 AM

Another reason is safety. In case of electrical leak from wiring and / or float switches, it is safer to run 12V though the tank than 120V.

jmait769 · 01/25/2007, 03:16 AM

Main reason is to keep 120V AC from entering the tank via a DIY kit. Also, the float switches use a reed switch with is not designed or rated for 120V AC however some have used them that way with no problems but why take the chance. Here is a good description: http://www.aquahub.com/store/curingspik.html
Saltwater is very conductive compared to freshwater!

HTH

Jay

scottwhitson · 01/25/2007, 06:08 AM

There are lots of float switches rated for 120 volts and you are generally using a submesible pump of some sort or heater that is allowing 120Volts to contact the water also. I was just wondering if that was the only reason. I have 120 volt float swithces and 120 volt relays and was wondering if there was any specific reason why not to use them?

mikeandjenn99 · 01/25/2007, 06:26 AM

I wouldn't see why not. I'd suggest a grounding probe in the tank though, just to be safe and protect against stray voltage.

Shagsbeard · 01/25/2007, 07:24 AM

I have a gravity fed one that works on 0 volts. I've never understood why people go with float valves and power pumps. Perhaps it's a bit more "high tech", but a siphon based system works fine too.

electricd7 · 01/25/2007, 08:12 AM

I have the nivaumat from AquaMedic. I HIGHLY recommend this one. It works awesome, and my tank is 100% always the same level. It was $100, but well worth the cost. I now just keep a 5gal container of water under the tank which lasts me almost 2 weeks.

goreefer · 01/25/2007, 08:28 AM

The arc created by 9 volts is LESS LIKELY than the arc created by 120 volts to weld the contacts when the switch is activated.
It is a safety measure to keep the ATO form overflowing your tank.

cristhiam · 01/25/2007, 10:26 AM

I use the double switch from autotopoff.com, works great.

ralphie16 · 01/25/2007, 10:31 AM

Quote:

Originally posted by mikeandjenn99
I wouldn't see why not. I'd suggest a grounding probe in the tank though, just to be safe and protect against stray voltage.

Not so sure about the benefits of a ground probe over its cons when used with a GFCI receptacle....

goreefer · 01/25/2007, 10:41 AM

I also use a double switch like what autotopoff recommends.
I use float switches from Graingers that are a little more heavy duty that what they sell. The HVAC industry uses many float switches for evaporative pumps. They are rated for longer use that the cheaper ones.
Same basic system though.
It works GREAT!

scottwhitson · 01/25/2007, 10:24 PM

goreefer the system you use is 120 volts or 12? The float switches I have are from Graingers also and they are heavy duty. I think that I will use this system as I think it will be safe with two float swithces and a relay rated at 100 AMPS.

mjm1969 · 01/26/2007, 10:11 PM

I'm with Shagsbeard. A topoff tank with float swith connected directly to my RO/DI = full tank all the time. Topoff tank connected to float switch in sump = 0 volts & no worries.

goreefer · 01/27/2007, 12:19 PM

scottwhitson,
I use a 12 volt relay to turn on/off two aqualifter pumps. My feeling is that it is not the 120 volts running through the tank, but the 120 volts welding the reed switches shut that worries me.
I have three 120 volt powerheads already in my tank, so the 120 volts is already there.
If you have never taken apart one of the float switches they are a simple magnetically activated switch. The magnet is in the float.
I use a old cell phone charger to power the relay. I think that it is 200ma, so there is not a lot of power to weld the contacts.
I use two of the aqualifters because one will not pump high enough to go from the bottom of my reservoir tank into my HOB sump. They are hooked up in series.

scottwhitson · 01/27/2007, 07:22 PM

Thanks everyone for the information.

01/25/2007, 12:08 AM	#1
scottwhitson Registered Member Join Date: Feb 2005 Location: Lewiston, Idaho Posts: 1,395	Auto Top off question?? I have been looking at a lot of auto top off systems and see that everyone is using 12Volt relays and 9 volt batteries to run them. Why couldn't you or why don't you use a 120 Volt relay and just wire it to use a regular plug in?? I don't understand the point of the 12volt relay system.

01/25/2007, 03:16 AM	#4
jmait769 -CSHFLW Join Date: Mar 2006 Location: Las Cruces, NM Posts: 2,685	Main reason is to keep 120V AC from entering the tank via a DIY kit. Also, the float switches use a reed switch with is not designed or rated for 120V AC however some have used them that way with no problems but why take the chance. Here is a good description: http://www.aquahub.com/store/curingspik.html Saltwater is very conductive compared to freshwater! HTH Jay __________________ "Opportunity is missed by most people because it is dressed in overalls and looks like work" - Thomas Alva Edison http://www.reeftronics.net/jay-m/reefcam Current Tank Info: 150 Gallon, Marco Rocks, 8x80W ATI Powermodule, Apex, Super Reef Octopus XP-3000 external

01/25/2007, 06:26 AM	#6
mikeandjenn99 Registered Member Join Date: Nov 2006 Location: Colorado Springs, CO Posts: 437	I wouldn't see why not. I'd suggest a grounding probe in the tank though, just to be safe and protect against stray voltage. __________________ Why are Tangs so special? Where are the Cleaner Wrasse police?? Current Tank Info: 55g mixed 12g nano

01/25/2007, 10:26 AM	#10
cristhiam Registered Member Join Date: Feb 2004 Location: Groveland, FL Posts: 3,099	I use the double switch from autotopoff.com, works great. __________________ 2 yellows tail damsels, yellow watchman goby, tail spot blennie, purple pseudocromis, starry blennie, 2 clowns, 1 black clown, mandarine & Yellow tang Current Tank Info: 125 AGA, 3 40W 6500K, 3 110W URI Actinics, running on 2 IceCaps 660, CSS125

01/26/2007, 10:11 PM	#14
mjm1969 Registered Member Join Date: Dec 2006 Location: Wasilla, Alaska Posts: 99	I'm with Shagsbeard. A topoff tank with float swith connected directly to my RO/DI = full tank all the time. Topoff tank connected to float switch in sump = 0 volts & no worries. __________________ Michael Current Tank Info: 120RR FOWLR Awaiting release from storage

01/25/2007, 02:15 AM	#2
Dubbin1 Registered Member Join Date: Mar 2004 Location: Findlay, Ohio Posts: 11,540	One reason would be for a power outage.

01/25/2007, 03:06 AM	#3
TekCat Registered Member Join Date: Sep 2005 Location: MN Posts: 3,130	Another reason is safety. In case of electrical leak from wiring and / or float switches, it is safer to run 12V though the tank than 120V.

01/25/2007, 06:08 AM	#5
scottwhitson Registered Member Join Date: Feb 2005 Location: Lewiston, Idaho Posts: 1,395	There are lots of float switches rated for 120 volts and you are generally using a submesible pump of some sort or heater that is allowing 120Volts to contact the water also. I was just wondering if that was the only reason. I have 120 volt float swithces and 120 volt relays and was wondering if there was any specific reason why not to use them?

01/25/2007, 07:24 AM	#7
Shagsbeard Registered Member Join Date: Jul 2006 Location: Morro Bay, CA Posts: 2,143	I have a gravity fed one that works on 0 volts. I've never understood why people go with float valves and power pumps. Perhaps it's a bit more "high tech", but a siphon based system works fine too.

01/25/2007, 08:12 AM	#8
electricd7 Registered Member Join Date: Nov 2006 Posts: 120	I have the nivaumat from AquaMedic. I HIGHLY recommend this one. It works awesome, and my tank is 100% always the same level. It was $100, but well worth the cost. I now just keep a 5gal container of water under the tank which lasts me almost 2 weeks.

01/25/2007, 08:28 AM	#9
goreefer Registered Member Join Date: Nov 2000 Location: Knoxville, Tennessee Posts: 825	The arc created by 9 volts is LESS LIKELY than the arc created by 120 volts to weld the contacts when the switch is activated. It is a safety measure to keep the ATO form overflowing your tank.

01/25/2007, 10:41 AM	#12
goreefer Registered Member Join Date: Nov 2000 Location: Knoxville, Tennessee Posts: 825	I also use a double switch like what autotopoff recommends. I use float switches from Graingers that are a little more heavy duty that what they sell. The HVAC industry uses many float switches for evaporative pumps. They are rated for longer use that the cheaper ones. Same basic system though. It works GREAT!

01/25/2007, 10:24 PM	#13
scottwhitson Registered Member Join Date: Feb 2005 Location: Lewiston, Idaho Posts: 1,395	goreefer the system you use is 120 volts or 12? The float switches I have are from Graingers also and they are heavy duty. I think that I will use this system as I think it will be safe with two float swithces and a relay rated at 100 AMPS.

01/27/2007, 12:19 PM	#15
goreefer Registered Member Join Date: Nov 2000 Location: Knoxville, Tennessee Posts: 825	scottwhitson, I use a 12 volt relay to turn on/off two aqualifter pumps. My feeling is that it is not the 120 volts running through the tank, but the 120 volts welding the reed switches shut that worries me. I have three 120 volt powerheads already in my tank, so the 120 volts is already there. If you have never taken apart one of the float switches they are a simple magnetically activated switch. The magnet is in the float. I use a old cell phone charger to power the relay. I think that it is 200ma, so there is not a lot of power to weld the contacts. I use two of the aqualifters because one will not pump high enough to go from the bottom of my reservoir tank into my HOB sump. They are hooked up in series.

01/27/2007, 07:22 PM	#16
scottwhitson Registered Member Join Date: Feb 2005 Location: Lewiston, Idaho Posts: 1,395	Thanks everyone for the information.