question about wc salinity

[stE26wy14]

ive recently been having a weird problem, im making my salt match the salinity to my tank or lower(<1.026), but whenever I do a water change, if its either 25-50%, my salinity always goes up. this has NEVER happened to me, my refractometer is calibrated to 35ppt(1.026), so that works, maybe its just me. But to keep a salinity level of 1.026 in my tank, and say that my salinity in my tank at the time (before) of the water change is over 1.026, what salinity should my wc water be?

 

[jpmazzone]

After you mix your salt, is the bin that you mix it in cold? You should test the new water for salinity at the same temperature as your tank. I keep a heater in my mix bin for this reason.

 

[Randy Holmes-Farley Verified Community Expert]

There’s no way that the salinity after a water change can be anything except the weighted average of the salinity of the new water added and the old water remaining.

As noted above, if the new water was colder than the tank, and the salinity of it was not properly corrected for that temp difference, then one could observe a salinity change.

 

[Bbio]

Are you double/triple checking with the refractometer? I’ve been noticing that mine is very fragile. I test the tank, new water, tank, new water and calibrate with RO and calibration solution alternating to make sure it’s accurate. Even the slightest amount of salt or RO left on the slide can give you a wildly off reading

 

[Gumbies R Us]

I would always make sure my water's temperature and salinity would match that of my tank before doing a water change. Never had salinity issues doing it this way.

 

[get-salty]

If your tank salinity is over 1.026 BEFORE the WC.

Still mix your salt at 1.026 for the WC.
Take out MORE than you put back in.

i.e. random #s here, dont do exactly this:
if you're doing a 5gal WC - take out 5.5gal and put back 5gal.
The ATO will kick in to fill the .5gal to lower the salinity.

 

[Fish Fan]

If it's helpful for anyone, both HamzasReef and BRS have a calculator to help determine what salinity water change water should be to reach a specific tank salinity:

https://www.bulkreefsupply.com/reef...n63AFAViecw9lGc8rkVv6gISeLM87LwC4fsBNZTAB-XPPhttps://www.hamzasreef.com/Contents/Calculators/DirectSaltCalculator.php

 

[stE26wy14]

so my tank + bucket temp when I measured was the same, I dont have an ato, I just top off myself with freshwater, I checked like 5 times with the refractometer
so idk, I am mixing before checking salinity in my tank, should I first check tank salinity then mix?

 

[get-salty]

Problem #1: No ATO brother
You can manually top off but the inconsistencies ....
That maybe your prob all along, your tank salinity maybe at 1.026 at start but i bet it goes south after a couple of days with that manual top off - unless you have a precise measurement.

 

[stE26wy14]

Problem #1: No ATO brother
You can manually top off but the inconsistencies ....
That maybe your prob all along, your tank salinity maybe at 1.026 at start but i bet it goes south after a couple of days with that manual top off.

I dont have space for a top off, and im pretty good at being consistent with topping off, and its such a small tank too

 

[Gumbies R Us]

so my tank + bucket temp when I measured was the same, I dont have an ato, I just top off myself with freshwater, I checked like 5 times with the refractometer
so idk, I am mixing before checking salinity in my tank, should I first check tank salinity then mix?

Is your refractometer calibrated?

You should always check your tank's salinity before doing any sort of water change.

Also, you can use a small bucket or get by with a small container for an ATO. It would be a worthwhile investment for you

 

[BeanAnimal]

so idk, I am mixing before checking salinity in my tank, should I first check tank salinity then mix?

Stewy!

Read what you wrote 5 times, then write it on the chalkboard 50 times. Then you will have your answer!

 

[Crabs McJones]

I dont have space for a top off, and im pretty good at being consistent with topping off, and its such a small tank too

small tanks have the biggest salinity swings. I couldn't imagine running my 25 lagoon without an ATO

 

[Randy Holmes-Farley Verified Community Expert]

so my tank + bucket temp when I measured was the same, I dont have an ato, I just top off myself with freshwater, I checked like 5 times with the refractometer
so idk, I am mixing before checking salinity in my tank, should I first check tank salinity then mix?

If what you say is true, and they seem to match at the same temperature, there can be no answer possible except a testing problem, not a procedure problem.