Salinity 1.03 natural sea water.

I would avoid the natural sea water due to the stated contamination issues. But yes natural sea water is usually higher than what the average aquarist keep in their aquarium. Natural sea water averages 1.026 - 1.036 and varies with storms, time of year, and even tidal movements.
I would be concerned with your TDS meter, as obviously it is well off. How is it possible to read .2ppm when you know you have over 300ppm of just calcium alone natural sea water should be well over 2000ppm through a TDS meter, in the very least.

 

Not necessarily when dealing with a natural source. We as hobbyists are used to all of the levels coinciding with each other because they are all contained in a pre-made mix. Generally, a higher SG will yield higher levels of the trace elements because the mix as a whole is more concentrated. But with natural sea water the elements all exist independently, so it is entirely plausible to have unusual balances between those trace elements.

 

plausible I dont doubt - mans intervention has made the contents of the sea, specially near the shore questionable at best

I believe he used his TDS meter to check his RODI and then used the RODI to calibrate his SG tester

I dont believe he measured sea water through the TDS meter or it would have been in the 1000s

 

Funny though isn't it? We do our best to mimic the ocean, refugiums designed after the Florida everglades – protein skimmers reproduce the foam of breaking waves on the coast and yet we don’t use the water mostly do to what we have done to it. Such a shame.

.....btw, I think the reason that shore line salinity is elevated is due to water evaporation.

 

seawater is usually 1.03 here too, i am in fl

nsw is fine, dont let the landlocked lead you astray, plenty of life in the ocean that use it. if you get paranoid about it you can run it through a micron filter, that removes most fish parasites if you use a micro sieve roughly 10 um. (I say roughly b/c there is no way I am buying those things are accurate ) You can also treat the water with chlorine, and then remove the chlorine later with heavy agitation and de-chlorinator like Prime\


the shore if anything will be lower, and is at times because of fw discharge, but you collect water at hide tide, and if there is no local inlet it wouldnt matter. the water offshore is pretty much the same. at least that is the case here, and probably the case where incognito was for ghost shrimp

 

John is spot on; water near the shore should be lower in salinity. Dont let people who have not tried NSW push you away from it. I have used 100% NSW in every reef i have had and it works just fine. Collect on an incoming tide in a smart location (not near large marinas/recreational areas) and you will be fine. Fish parasites are not really free floating so you really should never have a problem with that. I just collect it, heat if nessisary, and dump it in my tank. Our salinity is a little low so I have to watch that. If it's a bit high for you, you could always just add RO/DI water to lower the salnity before doing a water change.

 

Something I have noticed when calibrating my refractometer. If I use RO/DI water with 0 TDS to calibrate the refractometer, my tank water reads 1.03.

However if I calibrate my refractometer with a 35 SG solution my tank water reads 1.025.

Has anyone else tried calibrating with RO/DI and then with a known solution and found a difference?

 

Now I feel like gonig down to the ocean and testing my water. I live in New England. It would be interesting to see the difference, if any.