interesting salinity trend

[jbdreefs]

My salinity keeps trending downward. For instance, two days ago, it was at 1.20 ish. I disolved some salt in ro water and added it to the the sump: not a ton, but enough to bring it up aa point or two. I rechecked today... 1.19.

I am thinking that I may have a leak or my ato valve is slipping out of position; however, it feels really snug.

I am curious to know if you had a similar issue and what the culprit was.

About tank:

33 gallon long
20ish gallon sump

Gravity fed eshoppes ato
I recently started kalk wasser (1 gallon of solution diluted in 2 more gallons of ro water)
I have been running phosphate and nitrate sponge to get through a cyano problem. It is gone now
I am running phosguard and carbon in a reactor

There is some salt creep around the rim of my tank, I guess from all of my flow. The skimmer has some salt creep. Could yhis be it?

Maybe the sponges are stipping the water or more than they are supposed to?

Edit: I use a refractometer. I can provide other parameters but I am not sure that they would be useful.

Thanks in advance.

Edit: Oh, before you ask, I pull around .5 to 1 cup of skimmate a week.

 

[acroholic]

A water leak should be very easy to find if that is happening. I doubt salt creep would be the culprit either. If you maintain the same level in the return section of your sump you should have very steady SG readings. Also, did you mean to say 1.020 or 1.019. You are wy high in SG if those are your real reading.

If you don't have water leak, then I would guess your refractometer is out of whack and needs to be calibrated or replaced.

 

[franciscosalazar]

Could the ato be releasing excess water?

 

[acroholic]

If the ato is releasing excess water, he should be seeing an abnormal rise in his sump return section water level.

 

[franciscosalazar]

Acroholic;927217 wrote: If the ato is releasing excess water, he should be seeing an abnormal rise in his sump return section water level.

Is this the case?

 

[camellia]

My bet is your refractometer needs calibrating. I have to calibrate mine every time I use it!

 

[jbdreefs]

Thanks to all! I havent solved the issue yet.

Refractometer could be the problem, although I have taken very good care of it. Anyone have one that I can borrow for a few days? Or know where to get calibration solution.

Sump level stays constant other than when I let the ato reservoir deplete (not often).

I will into the refractometer.

 

[jbdreefs]

Look into...

 

[camellia]

Have you checked it with RO water? You can get the calibration fluid from ebay.

 

[rdnelson]

Using RO to calibrate will cause a false reading hat the desired level. You should calibrate with something close to the desired SP value to get it spot on.


I know you all think I have no heart but now I have an ultrasound to prove it.

 

[camellia]

rdnelson99;927570 wrote: Using RO to calibrate will cause a false reading hat the desired level. You should calibrate with something close to the desired SP value to get it spot on.


I know you all think I have no heart but now I have an ultrasound to prove it.

Wouldn't RO tell you what 00 is? Could you explain what you mean by "hat" please?
Im Always ready to learn.
Thanks

 

[jdwells]

Camellia;927228 wrote: My bet is your refractometer needs calibrating. I have to calibrate mine every time I use it!

This happened to me just a couple weeks ago. I had a really low reading so over a couple days I adjusted it up, then had it checked at Blue Planet and it was way high!
Check your tools, I bet that's where the problem is.
And be really careful correcting until you're sure. Good luck!

 

[jbdreefs]

I have calibrated with RO. The reason it is not as good to do so is because of the distance between your benchmark and desired outcome.

When calibrating, it is always better for the benchmark to be closer to the desired outcome.

On another note... I have been testing at night and morning. Higher in the morning and lower at night. I am wondering if I am having temp swings. Does warmer water have a lower SG with everything else remaining constant?

I meant 1.020 previously.

 

[rdnelson]

Camellia;927572 wrote: Wouldn't RO tell you what 00 is? Could you explain what you mean by "hat" please?
Im Always ready to learn.
Thanks

LOL "Hat" should have been "At".

The farther away for the point at which you calibrate the less accurate it will be. Therefore, using calibration fluid known to be near the target SP will give you the most accurate reading.

Edit:

JBDreefs;927576 wrote: I have calibrated with RO. The reason it is not as good to do so is because of the distance between your benchmark and desired outcome.

When calibrating, it is always better for the benchmark to be closer to the desired outcome.

On another note... I have been testing at night and morning. Higher in the morning and lower at night. I am wondering if I am having temp swings. Does warmer water have a lower SG with everything else remaining constant?

I meant 1.020 previously.

LOL Should have read your post before replying. :blush:

 

[sleepyreef]

If it is running low, then wouldn't calibrating at zero not be effective? If it was running high I could understand, but if it is running low then zero could still be wrong since SG doesn't go negative.

 

[acroholic]

JBDreefs;927576 wrote: On another note... I have been testing at night and morning. Higher in the morning and lower at night. I am wondering if I am having temp swings. Does warmer water have a lower SG with everything else remaining constant?

Not enough of a difference to explain your issue. See table:

http://www.engineeringtoolbox.com/water-temperature-specific-gravity-d_1179.html">http://www.engineeringtoolbox.com/water-temperature-specific-gravity-d_1179.html</a>

Most refractometers have ATC, or Automatic Temperature Compensation. If you have some instructions for yours, it should say whether it does or not.

 

[jbdreefs]

New theory....

Been storing unit on a shelf above the t5 lights. I am wondering if the heating and cooling of the refractometer could cause the calibration of the unit. Going to put it in the fridge for a little bit. In theory, this should increase the reading.

 

[jdavid]

Last night I wondered if my refractometer was off (calibration screw is rusted so it can't be calibrated) so I double checked it with two different brands of hydrometers. (Instant ocean, and Red Sea)

Refractometer- 1.026
IO hydrometer- 1.024
Red Sea hydrometer- 1.022

Big help that was. I'm going to order some calibration fluid, just to see where 1.025 is.

 

[jbdreefs]

leveldrummer;928344 wrote: the temp of the water should equal the temp of the crystal on the refractometer. You should let the water sit for a little bit before reading. You should not store the refractometer on top of the t-5 light, store it on a shelf or somewhere else in room temperature, do not put it in the fridge to check if it raises the reading. This is a precise instrument and exposing it to extreme temp swings isnt going to help it stay calibrated at all.

Disconnect your ATO and get your refractometer checked. top off manually for a while. till you sort this out.

Precision is the key thought behind my new theory. I had been storing the tool in an enclosed shelf that serves as my canopy. Lights are mounted directly below the shelf. While the temperature difference wasnt huge, the bottom of my refractomer case was noticeably warmer than room temp.

I am willing to bet that the difference in readings is caused by the temp of the tool. I cant think of many other reasons why the pattern of lower then higher would occur: other than those already discussed.

For what it is worth, I know better than to recover or change parameters too quickly. Even when my readings were low I added a minimal amount of salt. The next morning the salinity was reading high. At that point, I knew something was odd. From that point, I have more or less been observing and ruling out the causes.

I will post another update later when the refractometer returns to room temp. I hope this solves the mystery!

 

[tbub1221]

Have you recently drip acclimated a fish or coral and possibly forgotten to unplug the ATO ?
It is easy to do .
No doubt the temp swing can't be helping things either.