Tank aged water?

Hi Everybody!
Here's the question:
I am recieving all of the live sand and half of the live rock for my 125 gallon tank tomorrow. This will be a reef tank. The guy at the place who sold it to me said to watch the ammonia levels and be ready for some serious water changes if necessary. May not be needed, just be ready. OK, I get that.
But here is the deal: I have had saltwater in my tank for the last 2 months along with a two inch layer of Carib Sea aragonite oolitic sand. I cycled the tank with 3 grocery store shrimp back when I put the water and sand in. (figured couldn't hurt)
I was thinking that instead of throwing out all of the water that I displace when I place the sand and rock in the tank, I could save it. I could heat it and aerate it, like new saltawter, but this would be premixed and aged already. Then I could use this water for the potential water changes.
Could I do this? Any thoughts? I would appreciate any comments, as the LR guy wanted me to make new saltwater today to use for water changes later.


you may need more than the displaced water. You could probabally reuse it, but I'd have fresh mixed available.
Good luck!


Active Member
i too would reccommend mixing new sw. i would also however hang on to the old, just in case...teh only reason i woud reccommend mixing new water is because the old water could be totally devoid of th enecessary nutrients, if it has been running with corals and stuff in it for some time now!
anyhow good luck


I wouldnt use the water. The reason is you stated you used this water to cycle your tank with 3 shrimps. The nitrate level is probably high. If you try and use this water when you cycle your new rock you will see those nitrates sky rocket. Now you have a new problem..hair algae and maybe cynobacteria. It's not worth the risk in my opinion.
Thanks fror the input. I thought that this water would be OK 'cause there was no living creatures in the tank to aborb the nutrients out of it, just a layer of sand. The tank is done cycling, too. I will have fresh saltwater to use too, though. Basically, I am just going to cure live rock in my tank right now anyway.......