[cokipoint]

I am going to do a water change in my 150 gallon. I willl change about 25 gallons. I am using seawater that has been in a closed container for about 5 days.

My question is; if the water is still OK.

[demonsquirt]

I would say no. Then was it collected from the beach or 50 or miles out to sea.

Useing natural seawater is risky and takes some control away.

Mixing your batches with quality water assures you have the best source and eliminates this as any problems u may have in the future.

And any new batch should be kept moveing with some flow and if left more then 12 hours a bubbler would be helpfull and dark and room temp. is best.

[cokipoint]

I live in South Florida and the water comes from a company that delivers see water to the LFS for sale. The water is taken from the deep sea not the beach.

[jimw369]

Do what you want but I would test it for everything first. IMHO

"deep sea"?

[spanko]

I think closed container is a problem. If it is live seawater you bought from somewhere and has been sitting in a closed container for 5 or so days, there may possible be some die-off in the water and possibly some ammonia amongst other things. Jim is right, do some real intense testing of the water first, run some heat and circulation in it for a day or so, then go with what the data tells you from testing.
Again closed container is a flag for me that there is potentially something that may have gone wrong with this water.
JMO

[e_baer]

If I were to use natural sea water, I wouild put it in a container and run a good skimmer in there for a a bit. Also, good cirulation and fairly low temps.

[jimw369]

With all this being said is the "natural sea water" really worth it?