Water from the bay

[Karen Caleco]

I would like to pump the natural sea water into my reef tank as my top off. I live by the intercoastal waterway of the Gulf, under my dock you will find sea sponges and red sea fans with crabs snails, barnicales and fish. What do you think?

[Randy Holmes-Farley]

Karen:

Welcome to the forum!

I'd be concerned about pollutants from motor boats, fertilizer run off etc. in that waterway. Most people that use ocean water try to collect it offshore on a rising tide.

Still, there may be advantages to your setup if you pump it in frequently enough. It may add plankton, and it may keep undesirable tank pollutants and nutrients low (unless the waterway water is too high already). If you could change 10% per day or more this way ( or a large amount once per week) it might have interesting results. If the salinity of the waterway water is OK, you'd never need any additives.

I assume by top off you mean water changes or to fill an empty tank. Top off of evaporation water should be with fresh water as that is what evaporates. If you evaporate fresh water and add salt water, the salinity will rapidly rise.