The advantage of making water changes in your nursery tank using saltwater from the parent’s tank is that you know the new saltwater you are adding will be at the same temperature, pH, and salinity or specific gravity as the saltwater that the newborns are accustomed to, Lucienne. This assures that the newly added saltwater won’t be a shock to the delicate newborns, but you can accomplish the same thing with the Instant Ocean saltwater you purchase from your local fish store as long as you pre-adjust it to the same water temperature, pH, and specific gravity of the main tank before you make the water changes in your nursery.
Of course, if you are taking the saltwater from the parents’s tank to perform the partial water changes in your nursery set up, Lucienne, you will need to top off the parent’s take with freshly mixed saltwater that you have carefully pre-adjusted to the same water temperature, pH, and specific gravity as the main seahorse tank, so you will need to check those water quality parameters and make the necessary adjustments whether you are adding the newly prepared saltwater to the parent’s tank to replace the water you removed, or whether you are adding the newly prepared saltwater to your nursery set up instead, so just proceed with whichever method you find is more convenient for you.
Whatever the source of the water you will be adding to your nursery tank – or to the parent’s tank to top it off – just be sure to carefully adjust it to the proper temperature, pH, and salinity beforehand, and you can’t go wrong.
Pete Giwojna, Ocean Rider Tech Support