I have a water box 190.5 with a sump plumbed into the basement directly underneath the tank. My Apex keeps showing the salinity falling as low as 28. I have been boosting it up as high as 34.5 but it seems that only in a couple days it has fallen back down to 28 ish. I have double checked with my own meter and it seems accurate. I cannot find any leaks or any salt creep either in the sump, any of the plumbing , or the display area. My auto top off log looks fine , it only comes on a few times a day and only a few seconds. My skimmer is running dry, and I haven’t had to empty the cup. Does anyone know anything else that can suck up salinity?
Salinity constantly dropping
- Thread starter Glenng78
- Start date
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The refractometer confirms the apex readings. I am using a big 32 gal trash can for ATO. But my ATK is logged every time it comes on and it isn’t putting nearly enough fresh water to be diluting so much. I would guess a leak myself but I can’t find anything anywhere
Do you have an AWC set up? If so; have you confirmed that the source water is correct?
BeejReef
2500 Club Member
I would look into the return pump and/or the overflow drains. If the pump is running strong for some reason, or the overflow is clogged, the sump level will drop and the ato kicks in. Do you have a bean animal overflow? Is the emergency, emergency being used. Could be that it seems fine, but it's a slow building problem that usually happens when you're away from the tank.
BeejReef
2500 Club Member
quite a mystery. really sounds like you've got that tank wired for sound. hard to imagine what it could be.
Any chance of a siphon anywhere? Any ato or dosing lines making contact with the sump water that might start pulling a reverse siphon and kicking on your ato?
You know I was just thinking possible the ATO line was back siphoning into the reservoir, and then pumping RO into the system. The Neptune ATO kit has the top off line above water level though
NeonRabbit221B
2500 Club Member
+1 for reverse siphon. Check your ATO line and make sure it is at no point submerged. I did one with a reef-pi and found it diluting my salinity every time it kicked on....
BeejReef
2500 Club Member
I'm stumped.. lol.
That seems like a reasonable frequency and run time for an auto top off.
Maybe someone will have a eureka moment and figure it out.
Since your salinity is already all over the place, you might consider just disabling your auto top off for a day and then calculating how much rodi it takes to get you back to full. Then you'll have a solid figure for your evaporation and can judge if your auto top off is running too long for some reason.
Unless both your salinity measurements are faulty, then the only thing that can be happening is that you're somehow losing saltwater OR your total system volume is fluctuating. It has to be a leak, a reverse syphon, or an inconsistent water level.
Best of luck
That seems like a reasonable frequency and run time for an auto top off.
Maybe someone will have a eureka moment and figure it out.
Since your salinity is already all over the place, you might consider just disabling your auto top off for a day and then calculating how much rodi it takes to get you back to full. Then you'll have a solid figure for your evaporation and can judge if your auto top off is running too long for some reason.
Unless both your salinity measurements are faulty, then the only thing that can be happening is that you're somehow losing saltwater OR your total system volume is fluctuating. It has to be a leak, a reverse syphon, or an inconsistent water level.
Best of luck
Jon Fishman
Cleveland Ohio, buy/sell local!
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Automatic Top-off Kit. Proprietary Neptune/Apex nonsense
NoLobster
Community Member
You could check for a reverse siphon by testing the salinity of your ATO reservoir. If it is above 1.0 then salt water could be getting in there somehow.
Also is it possible your corals are using some of the magnesium and calcium and thus decreasing your overall salinity? It might be worth checking those parameters as well to see if the drops correspond.
Also is it possible your corals are using some of the magnesium and calcium and thus decreasing your overall salinity? It might be worth checking those parameters as well to see if the drops correspond.
