Help with dropping salinity.

[Bryon]

I'm about a month and a half into my tank. I check my salinity daily and top off as needed with RO water. The last few days I didn't have to top off at all. My salinity is dropping without topping off. I started using C-Balance about a week ago, dosing every other day. Would the C-Balance cause this? I thought there was a chance it would increase the salt, not decrease it. Is something else going on. Thanks in advance.

 

[returnofsid]

Evaporation will result in salinity climbing, requiring you to top off with Fresh Water. A leaky tank will mimic evaporation, but as you top off with Fresh Water, you'll notice a drop in salinity. I hope that isn't your issue but it's the only reason, I can think of, for a drop in salinity.

 

[Aqua Craft]

If you are using a refractometer, recheck for proper calibration.

 

[Fatman]

Two ways salinity will be lowered in the tank, salt creep and salt water being replaced by topoff water. The salt has to go somewhere. Salt creep shouldn't be significant so, my guess, is you have a leak somewhere. I have also noticed dropping salinity when I aggressively skim, lots of water coming out in the cup and the ATO putting fresh back in.

Fat

 

[Bryon]

I looked it over and found no signs of a leak. There is very little salt creep like you were guessing. I don't have an ATO. I manually top off, but haven't done that for a couple days. I do have to empty the skimmer cup every couple days. I also noticed after work today that my skimmer must have "burped". There was some spatter on my covers and on the floor.

 

[redtop03]

if you are skimming wet,the skimmer will remove more than you think,check that too

 

[returnofsid]

What is the size of your tank? Only in a small tank will a skimmer "burping" cause a noticeable drop in salinity and then, only if you're topping off, replacing "burped water."

How are you measuring salinity? I would suggest your equipment may be off and in need of calibration.

 

[Bryon]

if you are skimming wet,the skimmer will remove more than you think,check that too

What do you mean by "skimming wet"?

My tank is 65g. Right now I'm just using a hydrometer.

 

[returnofsid]

Are you rinsing your hydrometer after use? Hydrometers can "stick" and be unreliable. Rinsing them well, after each use, can help reduce this happening.

I'd suggest finding a LFS or another local hobbyist, with a refractometer, and having your salinity tested by their refractometer.

Are you noticing the water level in your tank dropping? You MUST be experiencing some evaporation, which WILL raise your salinity. There's absolutely no way that your salinity can actually be dropping, without an ATO, a leaky tank (leaked water replaced with top off) or over skimming (again, requiring skimmed water to be replaced by top off), since you haven't topped off in the past couple of days.

There's gotta be something wrong with your hydrometer.

 

[Bryon]

My lfs was closed when I got home and noticed it was low. I'll stop tomorrow and have them check my water and go from there. Thanks for your help everyone.

 

[Coraloliseffect]

Salt and gunk can buildup on the swing arm recommend washing / soaking with vinegar. Will remove deposits. Then rinse with water.

 

[Bryon]

Just regular vinegar? How long should it soak. Should it be diluted at all.

 

[Trex]

What do you mean by "skimming wet"?

My tank is 65g. Right now I'm just using a hydrometer.

When you empty your skimmer, is the "water" (( skimmate )) fairly clear, or is it dark like black coffee? Skimming "wet" will result in lighter colored (( more salt water in there )) skimmate.

 

[Bryon]

It's more like a brownish green. This is the first time I've used a skimmer so I'm still learning about them. Would raising the collection cup a little solve this?

 

[redtop03]

What do you mean by "skimming wet"?

My tank is 65g. Right now I'm just using a hydrometer.

if your skimmer is removing a lot of really wet skimmate,it is skimming wet,and therefore,removing a bit more saltwater than skimming dry,if that is the case,the ATO is replacing that with fresh water,thereby reducing your salinity...if the skimmate is thick,almost like mud,it is skimming dry

 

[redtop03]

It's more like a brownish green. This is the first time I've used a skimmer so I'm still learning about them. Would raising the collection cup a little solve this?

you probable have set it about right...how much fluid do you empty from it in a weeks time ?

 

[Downbeach]

A good refractometer is your answer here both now and going forward. I would make that my next investment, along with a bottle of calibration fluid.

 

[droblack]

Hydrometers are not be trusted. I agree, invest in a refractometer.

 

[returnofsid]

if your skimmer is removing a lot of really wet skimmate,it is skimming wet,and therefore,removing a bit more saltwater than skimming dry,if that is the case,the ATO is replacing that with fresh water,thereby reducing your salinity...if the skimmate is thick,almost like mud,it is skimming dry

There is no ATO involved and OP hasn't manually topped off for a couple of days, so this isn't a skimmer issue.

 

[redtop03]

The last few days I didn't have to top off at all. My salinity is dropping without topping off.

There is no ATO involved and OP hasn't manually topped off for a couple of days, so this isn't a skimmer issue.

you are correct Sid,I missed that in the first post..yep,if it were a skimmer issue,you'd definitely have to top off more often,same with a leak....I have no idea what's going on.....faulty refractometer/hydrometer maybe...IDK