Quick question on skimming

[Vincent100]

Hi all
Iv been doing alot of wet skimming in the last few days ,.my skimmer cup has been getting nearly full within a day
What I need to know is , is it salt water that is pulling or is it like r/o
The reason I'm asking this is
If it's salt water I'm pulling out its being replaced by my ato , which must be making my salt level go down ...I know not alot but in time it would go down
Can anyone clear this up for me
Thanks

 

[ruth howard]

It is removing salt water. Just test your salinity every so often. When my salinity drops out of range, I just put salt water in my ATO.

 

[smh254]

It's Salt water. You will have to check your salinity so it doesn't drop too low.