salinity, salt creep & top-offs

[dreams]

i am wondering, if a person was to not do water changes and only top-offs, wouldn't eventually the salinity drop because of salt creep & splashing?

not an important thing, just wondering

[charlie]

You are only replacing the water, the salt never goes away. Your salinity would probably end up rising. I am big on water changes, you need to replace the trace elements in your system.

[dreams]

i do water changes as well, but a lot of people don't

so, if you were only topping off and wiped off the salt creep, i would assume, that since that salt is removed, eventually, the salinity would drop

[kevinpo]

It would take a very long time but eventually it would drop.

Regards,
Kevin

[Joe Mac]

It depends on you definition of a "long time" I suppose. It also has a lot to do with with you "salt-creep potential", as it were.

But either way, you are correct. If salt creep is allowed to take place without "re-mixing" those deposits, then salinity will drop steadily, and over time, dangerously.

Frequent water changes are definitely the way to go, but be careful of dropping those salt-creep crusties into your water when doing so... they can my the salinity spike.

The best instrument ever created for aquaria is the refractometer. Period.

Joe Mac

[Ninong]

i am wondering, if a person was to not do water changes and only top-offs, wouldn't eventually the salinity drop because of salt creep & splashing?

Yes, the salinity would drop by the amount of salt removed in the salt creep. It would also drop by the amount of saltwater removed by your protein skimmer. This may or may not be significant, depending on how wet you skim. Water changes, assuming you mixed your new saltwater without regard to your tank's current salinity, would have no effect on raising the tank's salinity.

In other words, if you start out with 35 PSU (ppt) salinity in your tank and your water changes are exactly 35 PSU, then your tank's salinity will gradually fall over time, just less than it would have had you not done any water changes. Obviously you're not going to let this happen, so when you get ready to do a water change, you will check your tank's current salinity and adjust your water change salinity accordingly to compensate for any lowered salinity in the main tank.

The amount of salt that is removed by salt creep and protein skimming is insignificant in most situations, but it is measurable and your point is well taken. So yes, you should keep track of your tank's salinity and do your best to keep it steady at your targeted level.