consitant salinity during water changes??

[ProAccordV6]

During my 7-10 day 2 gallon water changes i'm finding it near impossible to keep a consistant salinity. I am mixing my salt before hand, usually a day or so, or just a few hours depending on how much time i have available. I like to keep my tank's salinity around 1.024 - 1.025, however, when i test the salinity a few hours after a water change, it always seems low (around 1.021-1.022. I am usually able to correct it within a couple hours by adding some salt water.

My question is; is this swing in salinity something i should be worried about since it isnt over a long period of time? And also, what methods of water changes have you guys/gals found is a good way to keep a consistant salinity? By the way, i am running a 12gal aqua pod.

Thanks in advance.

[rodd1rj]

Do you use a swing arm hydrometer, or a refractometer? It might be a skewed reading. I would also make sure the temps are the same when you measure. I think the salinity swings are worse over a short peroid of time because the fish, coarl or inverts have no time to adjust to it. I would say smaller water changes more frequently.

[drummereef]

What are you measuring with, a hydrometer or refractometer? Whatever you take out you put in, right? So if your water change salinity matches the salinity of your tank water, it should not change.

[ProAccordV6]

i'm using a refractometer.....maybe it could be the temps of the water.

[victor_c3]

<a href=showthread.php?s=&postid=9033728#post9033728 target=_blank>Originally posted</a> by ProAccordV6
i'm using a refractometer.....maybe it could be the temps of the water.

Yes, temperature would have a huge affect on the numbers you'd get from your measurements. A difference of even a few degrees could really matter.

Measure the sality of a sample of water then throw it in the refrigerator for a few hours and measure it again. The cooler water should should indicate that it has more salt in it. At least thats what it did when I did this experiment....

[ProAccordV6]

<a href=showthread.php?s=&postid=9034468#post9034468 target=_blank>Originally posted</a> by victor_c3
Yes, temperature would have a huge affect on the numbers you'd get from your measurements. A difference of even a few degrees could really matter.

Measure the sality of a sample of water then throw it in the refrigerator for a few hours and measure it again. The cooler water should should indicate that it has more salt in it. At least thats what it did when I did this experiment....

i'll give that a try. OK, assuming this is definetly my problem. What am i supposed to do, warm my change water up to 80 degrees, then measure the salinity and add, subtract according too haha. Or should i use a higher salinity assuming that it will lower once its mixed and heated with the rest of my aquarium?

[victor_c3]

I would set up a sample of water with the salinity perfect at the temperature that you use in your tank (1.024-5 at about 80 degrees?)

Then let it cool to room temperature and see what the salinity value is at room temperature.

Next time you mix up salt water, make it at room temperature and use the salinity value you just came up with from above and you should, at least in my theory, be good to go.

[victor_c3]

If it makes you feel any better, I'm a complete newbie here as well. I do have a degree in chemistry (although I have never used it in the 4-5 years its been since I graduated college).

I'm trying to figure out the whole salt water mixing thing too. I've only made two batches since I started my aquarium.

[ProAccordV6]

<a href=showthread.php?s=&postid=9035264#post9035264 target=_blank>Originally posted</a> by victor_c3
I would set up a sample of water with the salinity perfect at the temperature that you use in your tank (1.024-5 at about 80 degrees?)

Then let it cool to room temperature and see what the salinity value is at room temperature.

Next time you mix up salt water, make it at room temperature and use the salinity value you just came up with from above and you should, at least in my theory, be good to go.

that makes perfect sense. Thanks!!!

[Doglover_50]

I've read that you should NOT overshoot your salinity, then adjust to bring it back down. Alkinity crash or something like that.
Seems like starting your fresh water at the same temp as the tank, then doing your mixing, would be safest.