A stupid question regarding protein skimmer

[mrhasan]

I run a rio protein skimmer and it is collecting good amount of "brownish" water in the cup. I was just wondering, the water that protein skimmers collect, is it just liquid waste or water from the tank with the junk? I do have to top-off with fresh water every 4/5 days due to evaporation but would also like to know whether skimmers removes some saltwater too.

[Mandosh]

Your skimmer will remove a small amount of salt. The amount is dependant on how wet/dry you're skimming, but in either case it's pretty much negligible.

[mrhasan]

So its actually very small amount of "saltwater" and mostly junk? Like, if I get a cup of brownish water, I don't always have to replace the tank with a cup of saltwater to maintain the same water level right?

[Mandosh]

No, you don't have to replace the skimmate with new water.

[mrhasan]

Thanks

Actually I am running a rio nano skimmer in my 20 long and its sucking up good amount of junk esp after adding few frags of softies (good that it has a big cup compared to some other HOBs) so thought whether or not I need to replace the same amount of water with saltwater.

[Myka]

Just check your salinity. If you find the salinity has gone up by 0.001 add some freshwater. Make sure you are using a hydrometer that has been manually calibrated or a refractometer that you calibrated a few times per year.