Salinity drops too fast evryday please help

[james-lee]

Hi my salinity drops a whopping .03 - .04 within a 24 hour period. EG in the am Ill use my refractometer and I will have SG of 1.025. By next morning before I leave for work it will be 1.021 or .022. Skimmer is set to more of a dry skimming and I have covers on my tank and sump and equipment is in the stand. Tank is 225 witha 55 gallon sump. I run a CSS 220 skimmer with a 1000 gph return pump and a fluval FX5 for mechanical filtration. I use 4 tunze turbelle 4002 for water flow within the tank. Any advice would be appreaciated!

 

[smtank]

Do you have a ATO? I can understand going up in SG, but not down like that unless the temperature swings in your tank are extreme.

 

[james-lee]

Yes I have an ATO drilled in on the rturn side of my sump chamber thats hooked up to my ro/di system (sorry forgot to mention that lol). Also temp ranges from 79 in the am to 82 by the time the lights shut off. Is that too extreme?

 

[ToddG.]

I would say you have a leak somewhere or your skimming way to wet or your refractometer or what ever your using is very temperature sensitive

 

[james-lee]

Well would the sump area getting pretty warm be an issue then? Cause it does get hot under the tank in the sump area. I am going to install two 12V fans on both ends to help draw cooler outside air in and remove the hotter air out. Dont know if the heat causes salt to dissipate into the air quicker or not.

 

[shifty51008]

salt does not evaporate so the heat won't cause that.

 

[james-lee]

Well then I am at loss. I dotn see any leaks anywhere and I calibrate my refractometer all the time and it compensates temp already.

 

[Randy Holmes-Farley]

Is the ATO keeping the water level constant?

 

[RegalAngel]

Your skimmer is too wet....dumping SW and the ATO makes up with FW...Bingo.

 

[james-lee]

I make about of cup of dark skimmate every 3 days or so. Ill try to adjust it to make it more dry then. Hopefully that helps. Thanks guys for the advice!

 

[bertoni]

A cup of skimmate every three days isn't enough to change the SG noticeably in a 225 g (o 225 L) system. Something else is going on, either a measurement problem or some other water leakage.

 

[jimrawr]

Are you sure you are reading the refractometer correctly? Make sure the whole palate is wet and no air bubbles as it will throw the readings off

 

[james-lee]

Yeah I have ensured there are no bubbles. Still reading low after adding some premixed saltwater again. I dont see any leaking of the tank or pipes or sump. Could salt just be creeping out of the sump area?

 

[shifty51008]

do you calabrate your refractometer with a 35ppt soultion? even if you get some salt creep it won't drop it that fast.

 

[james-lee]

No I dont the manual it came with said to use distilled water.

 

[Mothercolony]

The solution made by salifert costs less than 8$ to calibrate your ref. correctly.

My guess is the float on your RODI might leak in the sump even when it's suppose to be off. Do you have a marker line where your waterline is in your sump so your consistent?

 

[preef]

You can always take the ATO off line for a day or two and verify that the salinity isn't going down.

Have you measured how much top off water is going in every day?

 

[james-lee]

Yes I have marked line and its does go down to a point to where the ATO goes off. I havent measured the actual amount of ATO per day. The only thing new I added since this started happening (this often) was my fluval fx5 as a mechanical filter and media reactor. Ill also order some calibration solution too.

 

[jherrin215]

Get the calibration solution ASAP. Guarantee the problem is a mis-calibrated refractometer. Had the same issue myself.

 

[Randy Holmes-Farley]

I'm not sure how a single miscalibration makes the salinity drop over time. It would just make it always read a little higher or lower than actual, assuming it is a fixed miscalibration, like calibration with distilled water could cause.