[Ogdenenator]

Currently I have about 1.5 - 2 inch curshed coral bed in my 20 gallon tank.
I want to start keeping corals, im trying to get the water and everything right before i try putting in corals. I want to switch to a 2" sand bed.

What would the impact to my tank be if i removed all the live rock and fish and put them in a holding tank. Removed all the crushed coral. Put the sand bed in with the live rock. The whole time i would keep about 50% of the current tank water in. Replace the water, add the fish. I should be done then right?

Any feedback???

[charlesr1958]

Yes, that should do it. With one exception, I would not leave any of the water in the tank that was in there during the removal of the crushed coral. It will most likely be toxic or at the least, just plain "nasty". Once you have removed the crushed coral, remove all water and throw it out. Other than that, you should have no issues other than a chance of ammonia which you should monitor for a few weeks after the change.

Live rock / sand

Chuck

[rjs5134]

Chuck, why would the water be "toxic"??? I will be draining my tank on Saturday to change stands and hope to replace my well seasoned coral base with a sand bed. Wouldn't it help to keep a small amount of crushed coral to seed the sand bed? Obviously it wouldn't have everything present in a DSB, but I know the CC bed is loaded with life.

Rob

[zhenya]

I think what Charles was trying to say is that if you leave a bit of water on top of the sand/crashed coral bed, and then disturb either one, the water will become quite toxic. I agree wholeheartedly with that estimate.
Having said that, you can certainly drain as much water as you want to save from the tank and store it in a container, providing that you will circulate it with a powerhead or something to that extent. After you done with removing the sand, then whatever water left should be discarded.

As far as leaving some of the CC, I think you can do it but be aware that it will eventually rise to the top as the smaller particle sand will settle down. You can leave a cup ot two to seed the new sand, I've done it in my anemone tank without incident but the crashed coral eventually comes to the top and you need to either remove it gradually and replace it with fine sand or be prepared to syphon crud that is trapped in it. In my opinion it is counter productive.

[CSeaSee]

I'd also like to say that your live rock will have many of the same critters on and in it that your CC has- you just never see them on your rock because they're hiding during the day. If you start your sandbed and keep your live rock but ditch the CC (I would), the sandbed will eventually become colonized with life.
And this is coming from someone who has CC...

[Ninong]

Originally Posted by rjs5134

Chuck, why would the water be "toxic"???

What he's saying is that you should remove the water from the current aquarium before you disturb the crushed coral substrate. Any water that is still in the aquarium when you begin taking out the crushed coral substrate should be discarded. That should be very little if you drain the water down to the surface of the crushed coral bed before beginning to remove the crushed coral.

I will be draining my tank on Saturday to change stands and hope to replace my well seasoned coral base with a sand bed. Wouldn't it help to keep a small amount of crushed coral to seed the sand bed?

I wouldn't do that but if you do go that route, don't keep very much of it.

Obviously it wouldn't have everything present in a DSB, but I know the CC bed is loaded with life.

If you're talking about macrolife (stuff you can see with the naked eye), then you can salvage some of that -- polychaete worms, etc. As you remove the crushed coral substrate, place small portions at a time into a shallow pan with a small amount of tankwater. Gently stir until you see some worms or other critters at the surface. Pour those off into a separate container. Repeat as necessary. Return these critters to the new sand bed in the tank. This only works for things that are large enough to see.