Salinity keeps rising up daily,help (why?)

[dpsa98]

I have a 46Gal bowfront mixed reef tank with a 20 gal sump. My water perimeters are
PH 7.8
Nitrate 0
Nitrite 0
Ammonia 0
Phos 0
Salinity 1.026 (Today)

I do weekly 10% water changes and I try and top off my sump every other day from the evaporation. I keep my mixed water at 1.024. My question is every other day my water seems to rise to 1.026 . If I miss a day or two with my salt free distilled water my salinity goes through the roof. I went 5 days without adding top off water recently and when I checked my salinity my tank was at a 1.030. Do any of you have a clue as to why my tanks salinity raises up so quickly. I keep all of my equipment clean. I wash out my skimmer every week. Any suggestions or help would be appreciated. I almost lost some zoo's because of the high salinity and my BTA's seemed to thin out and not be (BUBBLY)LOL...Anyway my salinity is at a 1.026 and all of my livestock seems to be just fine for now.

Thanks,,
Dave

 

[dpsa98]

Sorry, I forgot to add my tank is over a year old now.

 

[zoomfish1]

I target 1.026sg. That is where you want it for a reef. It probably rises because of the greater concentration when you need to top off. Not much to worry about as long as it goes back down when you top off.

If you almost lost zoas, I would think the problem was not sg, but something else going on. Try to keep the sg at 1.026 and everything will do fine. Only bring it up 1 point per water change so you don't shock the tank.

 

[Sk8r]

The only thing I can think of, granted you know [and after a year, you must know] to top off evaporation only with non-salt water, is that salt creep is getting back into solution: salt creep is the white crust that develops where there's spray. That's a ferocious climb in salinity.

First, I'd get a sealed [lidded] topoff bucket [ro/di] plus a topoff valve---75.00, about, from autotopoff.com that will sit in your sump. That will send whatever's in the topoff bucket to your tank at a rate of about a tablespoon a swat, as needed. Much better than the highs and lows of hand-topping.

Second, I'd suggest testing the calibration of any salinity test instruments. I hope you're using a refractometer: the swing-arms are notorious for misreading---a single microbubble on the swingarm and you've got an error.

Third: set your basic salinity at 1.025. THat's a good median reading that gives you .001 to be wrong with before you're into damaging territory.

Any of these things suggest any fixes?

 

[dpsa98]

Thank you both for you quick reply. Sk8r you have helped me quite a bit when I first set up my tank....Thank you again. I do use a refractometer (at a previous suggestion from you I belive). I like the the sealed bucket with topoff valve Idea. I think I will see if I cant pick one up this weekend. I only change my bucket on my skimmer but I do see a lot of salt creep in my sump especially on my return line to the tank should I wipe that off at each water change? Could it make a .001-.002 change that quickly by itself?

Thank you both again for your assistance,
Dave

 

[Sk8r]

dpsa, it really shouldn't make that much difference with just the salt creep alone, though it may be a factor. I'd just knock it back into the sump on a regular basis, to be sure you aren't losing salt, then adding more.

My picture of what's probably happening: cumulative error plus salt creep. Good for your having that refractometer. Be sure you squirt ALL the water out of the bulb when storing, because that evaporation can make a huge error in reading at your next test: you're getting the salt from TWO water samples if that hasn't cleared out.
If you make a bobble in testing and give it the slight benefit of the doubt on the high side, and do this several times [you said you're pretty frequent with water changes] it can creep upward on you pretty fast. THat's what I'm thinking, that it's tiny variances adding up with a little salt creep. Good thing you DID test your water or you'd be losing specimens and wondering why. Err very slightly on the low side: it's easier to add a little salt to get it up rather than let it creep too high. Also, and just a curious thing with refractometers---are you angling it the same way for testing the new water as well as when you are testing the tank? There can be a hairline difference in interpretation depending on the angle of viewing. I doubt that'd be enough, but if it's a cumulative error, everything's suspect.

Re the topoff, the way that works is, at least for the autotopoff.com version, ---you put a dualswitch float in a hanging clip in your sump, set the display lights in front of your tank, [connected by wire] and plug the thing in. It has one more plug in. THIS goes to a pump [I use a Maxijet 1200] in the lidded freshwater topoff bucket, and you notch the rim of the bucket so the hose can get out, and back to the sump, where you set it so it won't fall out. By using an old salt bucket [most are 7 gallons] you have quite a few days before you have to mess with the topoff. You'll know when you hear the topoff pump running and running with no cutoff. This means you can also take a week's trip and have your tanksitter just add a new bucket of topoff refill water to the reservoir, never touching your actual tank or sump: this can be a good thing.

Note: do bore a small hole in the hose before it leaves the bucket, so it will break the siphon: otherwise the two water sources will try to equalize when the pump goes off, and this is a soggy experience. [Been there, done that!]

 

[jlynn427]

i agree

 

[dpsa98]

Thank you again. I will post how things work after I get everything set up this weekend....

Dave

 

[Vanquishxxxx]

well if you miss a day and lose jstu liek one gallon of water in a 46g tank that can most deinfitly raise your salitinity significantly because no salt is leaving the tank but freshwater is , so you have more salt and less water making your salinity rise, jsut keep up on topping off and you shouldnt have a problem

 

[bbehring]

Just a quick question. Is the pure water top off considered in part and parcel to dumping the skimmate cup and topping off due to this volume loss too? I'm wondering if you keep dumping your skimmer cup (not that it's all that much liquid), weather this can effectively lower the SG, since replacement is via pure water top off? Just was wondering. Top off always seems to be equated to evaporation but nothing mentioned about the liquid in the skimmate.

 

[Sk8r]

THank you, bbehring: strong skimming could certainly contribute to the puzzle, exactly as you describe.

 

[bbehring]

I'm just curious, as it seems this has happened to me recently, that the dumping of their skimmate over time, and simply replacing with pure water through the evap/top off process as standard protocol, that the SG might/will slowly depleate?

 

[bertoni]

The skimmate contains salt, so if the skimmate is replaced by fresh water, SG will drop over time. Using 2-part supplements like B-Ionic will have the opposite effect.

 

[techreef]

a small addition to sk8r's autotopoff instructions: if you don't want to drill the syphon-break hole in the autotopoff tubing, there is an easy alternative. just make sure that the outflow end of the tubing is never underwater in your sump, and it will never develop a syphon. I learned this the hard way when I emptied about 10 gallons of FW into my sump one day. Upon inspection, I saw that the autotopoff tube end was under water in my sump, which allowed the FW to continue flowing after the switch turned off the autotopoff pump.

autotopoffs are one of the BEST additions to tanks IMO. I hated having to remember to top off daily, and if you don't have one, you can't vacation for any real length of time. My 20G FW reservoir gives me about 7 days of worry-free vacation time.

 

[hmello@bermexin]

Sorry for the dumb question but have you calibrated your refractometer?