Does a skimmer remove saltwater?
 

as a skimmer skims and the skimmate accumulates in the cup, how much of the skimmate is saltwater?

my concern is if overtime saltwater is removed through the skimmer and is replenished with fresh auto top off, will it eventually start lowering my salinity?

It does but it has never been an issue for me. It's really a small issue if you continue monitoring your salt level and keep up water changes.

My skimmer runs very dry so really only about a cup or two a WEEK of liquid removed.

It's probably only an issue on really small tanks. On something like a 90 gallon or larger, the amount of salt water removed by a normally operating skimmer would probably take months to noticeably affect your salinity.

My skimmer removes about a cup of dark and chunky skimmate every 2-3 days.

And now that I've dialed in my refugium with the right amount of flow to lower nitrates to 0. I probably won't do frequent water changes. I'll just be dosing

Nitrates should be zero.

Not convinced you can "dial" in a fuge to control nitrates at all. I know it's there to assist removal but any visible reading if nitrate is direction relation to what we do.

A skimmer an fuge won't change the need for water changes at regular intervals. Maybe that's why you have nitrate, cause again, the reading should be 0.

Good luck.

well i went from about 10ppm nitrates a month ago, to it being 0ppm nitrates.

and the only thing i changed was i added cheato, increased flow in refugium and keep the lights on for 22hours a day.

no water change in that time and the nitrates magically dropped

water changes help maintain ionic balance and replace trace elements

but so does dosing those trace elements, right?

you should test for everything you dose to ensure you are not over or underdosing but the best way to replenish trace elements is with water changes because the elements are in the proper levels and you can't overdose, if you dose trace elements then you will probably get the concentrations too high over time and you can't test for all the trace elements. a 10% monthly water change would suffice.

yeah maybe ill do a small water change.

i've started testing my water with hanna checkers