Tank top-off system ideas?

You could use an aqualifter pump (or something similar) to pump from a container of limited size that would hold water for a day or two.  You would just have to run a small water line to top of the tank somewhere.  The pump could be on a light timer and setup to run just long enough each day to replace your evaporated water.  You would still have to refil the tub (either by a float valve from an RO/DI, or manually), but it would probably be less often than you are doing now.  Again, it relies on a timer that could possibly fail, but if the container is sized correctly a timer that failed in the "on" position would only add as much water into your system as it could handle without overflowing. 

There are also some commercially available auto-top off systems that you could use instead.  I've seen some at Marine Depot.com, but they are rather expensive and also rely on some sort of float valve to operate.

IMHO, without a sump or without using float valves of some kind, I think you are kind of limited on options. 

Hope this helps.


Edited by TNaisbitt - November 13 2008 at 11:08am

If a snail gets on the float valve and keeps it from floating it will keep filling until the snail moves on or no more water for the top off.

Here is something I came up with a while back, might not be what you have in mind, but it worked for me =) http://utahreefs.com/forum/forum_posts.asp?TID=23156&KW=float