Help adjusting Tunze ATO 3152 -- too much water!

[JingoFresh]

I have the Tunez 3152 ATO, which I am very happy with the quality and it seems great in general, although I have a problem I don't know can be solved.

I have my sensor and the output line both in the sump. The problem is that I am trying to maintain a specific salinity of 1.026, and it seems to pump too much water in.

The manual only has an option for increasing how long the pump runs for, using a jumper to change from 1.8 minutes to 3 minutes.

There doesn't seem to be any option to have it run for less than 1.8 minutes, which is too long for me.

I don't have a siphon, as the water in my container is lower than my sump.

Do I have any options, or will I have to find an alternative ATO?

 

[rvitko]

The controller timer is only a backup if the float fails, the float should be shutting it off as soon as the float gets near the top of the post, if the float is not turning it off, either their is a siphon (this can happen if the end of the hose at the sump goes further into the sump than the reservoir is high, for example your reservoir is 12" high, your sump is 16" high but the hose hangs into the sump 6" making the difference 12 vs 10 so 2" could siphon from a full reservoir. All that matters is end of the hose must be above waterline in the reservoir.) Or the other possibility is that a magnetic field is affecting the float, the float is a magnetic switch, the black ring in the float is a magnet and it flips a switch in the post when it moves. If another magnet is nearby or the glass is very thin, the magnet holder itself can affect the float, the float will not move and may appear to lean as if repelled or attracted by the magnetic field. Move any other magnets away and if needed add a shim between the outside magnet and the glass, usually a piece of 1/8" thick acrylic, rubber or a piece of an old mousepad or koozie will do the trick.