In preperation of my new 88gallon tank, i have been saving some of my wastewater from the last 10% change. And last week I moved the 36gallon to a new room and placed the 88gallon in my living room. That day I did a Substrate change in the 36, and took some decoration out.

I placed all the wastewater and substrate i could into the rubbermaid container holding a ton of wastewater. Along with some old pads and filter material I removed about 2 weeks ago when I did my filter change.

I am wondering if this water will be feasable to use to start a fishless cycle? I plan on starting the cycle next week, and I guestimate I have about 15-20gal of water and about 40lbs of substrate sitting in this rubbermaid container. Its been in my garage for about 2 weeks and am not sure if its gone stagnant. There is no aeration, and it was getting down to the low 50's at night, so the water has been nowhere near the 70-80 degree's i had hoped for.

I was planning on running a few tests on the water before I started the cycle to see where i start, but im wondering if the cold weather and niglect would let the nitrate die off?

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Old water does nothing. There is no way I'd start a new tank with water from another. The water won't help your cycle, but things from your other tank will, like handfuls of gravel, used filter media, decor from the other tank, etc.

Ok then forget about the water.

The rubbermaid container with the water in it, has about 6" of substrate at the bottom, along with some rocks, fake plants and padding from my canister filter.

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I would use it as long as where it came from was a fully cycled / disease free tank. A quick rinse in some dechlorinated water wouldnt hurt any thing if needed.

+1 on use new, clean water.

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Do fish get thirsty?
How to fishless cycle your aquarium http://www.aquariumforum.com/f66/fis...cle-15036.html

Information on API FW test kit http://www.aquariumforum.com/f2/api-...ion-15347.html

The beneficial bacteria you want typical sticks to just about every surface, but very little is free in the water. The good thing about keeping the water is that you may have kept alive some of the bacteria on your gravel, decorations, etc. To keep the bacteria alive, they need to be kept wet in dechlorinated water and have a food source. With that much old gravel, I'm guessing you had a little bit of dietrus or decaying plant food, which should be just enough to keep some of the bacteria going.

As long as the tank was healthy, I would just put a few scoops of the gravel in a mesh bag and drop it into your new tank. A decoration or a few wouldn't hurt either. Just make sure your new tank also has a food source. There are many options for this including several threads on this forum for fishless cycling. The simplest is probably to throw in a few fish flakes to start decomposing in the new tank the day before you transfer the gravel.

The nice thing about the mesh bag for the gravel is that, once you've seen the tank cycled (by following the water chemistry), you can easily take it back out if you want.