new to hobby

[shootist]

I am attempting to set up a new tank for seahorses. My husband has an elaborate setup and is experienced in reef care but not seahorse care. I am starting small just to see if I am able to keep them alive and thriving. I am starting with a 10 gallon hex tank, standard hood and light that was included. my husband bought the heater and hand on the back filter, I trust he knew what he was doing. My question is....I put black sand in it and my husband said I could take some sand from his tank that has been set up for over a year now. How long do I need to wait to put his and in to my tank. He put 5 gallons of water from his tank and 5 gallons fresh saltwater in there. We did it this morning. Can I go ahead and add his live sand to the tank or should I wait a few days. We haven't tested the water or anything yet. He said to wait a few days but I am impatient... I have been reading over the forum but any and all advice is welcome. I haven't read much about success rate in such a small tank though. I am planning on a larger tank if I am successful but probably only a 20 gallon or so.