CC to LS - last few Q's - tomorrow is D-Day!

[auntynatal]

Ok, tomorrow is D-Day and I pick up my live sand tomorrow afternoon.

I intend to empty the livestock corals and LR from my main tank into a second tank in the morning, spend lunchtime clearing out all the CC (and take a razor blade to all the spots I couldn't reach before and get the green crap off the back) and then put in the LS.

Questions!

1. How deep should the sand bed be? I have read that anything from 1" to 4" is acceptable but are there reasons for different depths? (I've ordered 80 lbs for a 55g tank - rather throw some than not have enough)

2. I've got 40 litres of saltwater in a bin circulating and heating (which is more than I will need, but again better safe than sorry) I estimate I will lose about 25 - 30 litres of SW during the changeover. Once I have put the sandbed in, should I put in as much saved water as I can and then some new water in and leave it to settle?
How long should I leave it to settle?
Will I be able to put my fish etc back the same day as the bed goes in?

I'm still bricking it but I know I have to do this for the good of my tank and its inhabitants. not looking forward to catching fish, especially not Nigel the boxing shrimp as he is testy as hell at the best of times! any tips on fish and shrimp catching techniques?

Thanks in advance, as always!

[dcombs44]

My first thought (and I'm not totally sure) is that totally replacing your substrate at one time may cause a massive cycle and all but crash your tank. Granted this isn't a deep sand bed that you're removing, but you may be taking away enough of the bacterial base that the remainder has trouble catching up. I'd wait for some more people to chime in on this, as I'm not completely sure what type of effect you'll cause, but I'd wait until you hear.

As far as removal goes. Remove the rock first and then net out the livestock. They will have nothing to hide behind at that point and will be easier to catch.

As far as sand bed depth, if you're going for a shallow sand bed, a couple of inches (2-2.75") will probably be fine. I think you're right in saying that a sand bed becomes classified as a DSB at around 4 inches.

Good luck. I'll stay tuned to see what others have to say.

[auntynatal]

Bump for advice re previous post.

[Toddrtrex]

I did something similar a couple of months ago -- but I changed out all the live rock too. (( new live rock had been curing for a month and a half )). I didn't lose a thing, and when I tested my water a week later all "bad" numbers were zero.

Here is the thread I made about it.

http://archive.reefcentral.com/forum...readid=1233581

[dcombs44]

Well there you go, and coming from a Team RC member no less. I guess if your sand bed isn't a DSB and serving a major biological purpose, then you may be ok with the live rock bearing the load.

Thanks Todd.

[ninjamini]

Just keep your fish and corals in a tub with water, heater and powerhead. Thats fine for a month or more. If you really want to treat them nice throw some of the live rock in there as well. They will be fine. They do this for QT.