Will this work for part of an auto topper?

http://www.usplastic.com/catalog/pr...ic&category_name=6109&product_id=5855

have a topper container hidden in the stand and flowing into the fuge / sump. The float itself would also be in the sump since I'm assuming that the water level in the fuge will go down along with water in the main tank.

 

How about this much less expensive one....

http://www.marinedepot.com/md_viewItem.asp?idproduct=KM1675

and actually, JUST the water in the fuge will go down because the overflow in your main tank is set at a fixed level ;D

 

Or if you want something a little fancier either of these work very well http://saltycritter.com/waterlevel.htm and are still cheaper. I use the spectrapure unit on my tank with a maxijet 400

 

Those are pretty cool Shawn.
How far does the water drop before they are activated?
What sensors does the Reef Fanatic one use?

 

The Reef Fanatic one uses two typical float switchs similar to the M8000 here. The reef fanaticuses two of these in various configurations one way one is a back up to the other, in another one is in the sump and the other in the top off bin. Here is a link to the manual that shows it MANUAL


The spectrapure uses air pressue to kick it on and off and lets my level change about 1/2 or so in my sump before it turns on/off.

 

Birdlady: what if the fuge is a hang-on model instead of an underthe tank model... then wouldn't the tank and fuge have the same water level ? I never checked it but I have a hang-on unit and my tanks water level drops 1/4 to 1/2 inch per day.

I'll mark my fuge levels to see if they mirror the tank.

 

if it is a hang on model that water is pumped to then overflows back to the main tank the water line in the fuge should not change and should be constant

 

How about this one:

http://www.floatswitches.net

I recently got several and they can handle a 50 watt pump. It turns the pump off and on instead of stopping the water flow!!

 

how do you hook those up dx?

 

Crutkas:

Here's a link here on 3Reef:

http://www.3reef.com/cgi-bin/yabb/YaBB.pl?board=DIY;action=display;num=1087168041

Basically just get an extension cord, cut one of the wiresand splice the switch in between the cut wires, plug in the extension cord and plug the pump into the end of the extension cord.

Don't exceed the 50 watt load limit on the switch. There are some links on the same page as the switch that have float switches that can handle 100 watts and more. They are a lot more expensive but you will need them for larger pumps. ;D

Here's a link to the unit I am going to put on my retutrn pump for my display tank:

http://www.spectrapure.com/St_alc_p3.htm

Hope any of this is helpful!!! 8)