OK I'm i need of help soon, I'm getting ready to set up my 125 and since its my first saltwater Ive been doing lots of reading and would like to get the ball rolling, but Ive been finding people saying to use it for the base rock to keep from moving and preventing from rock slides and fish digging under the rock. me personally it doesn't matter as long as its right or at least a good reason for it, i just would like to get this figured out so i can get the tank cycling

I don't think egg crate is necessary. As long as you place your rock in the tank and then substrate, that should be stable enough even with fish digging under it. Having a deep sand bed (at least 3 in) should help with stability too. Welcome to the saltwater world! It's a great place! Glad to hear you've been reading and taking your time; that's the best way to succeed. Please ask as many questions as you like!

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When in doubt, do a water change.

I don't use Egg-Crate but my sand is only 2 inch deep so I can get the rock to touch the bottom of the tank easy, it is not needed, if you stack the rocks properly they won't fall over, something digging under the rocks in the sand could make them fall over but that is only if you are going for a deep sand bed with the the rock not touching the glass.

If you are going to do a deep sand bed then it prob is better to use it, I wouldn't do a deep sand bed myself and since this is your first dip into saltwater I would advise against it also.

You can also use the Egg-Crate to build stands for rocks to go on and then place the other rocks round it so you can't see it to make your tank look nice but.

Yea, you probably wont need it. You can putty together all the rock to make sure it remains stable even though stuff underneath may be moving.

If I move my rocks about I just give them a good jab with my finger, If a good jab with my finger won't knock it over Im guessing a fish won't either.

We are getting ready to set up my 150 gallon reef. We are using egg crate and keeping a 4" gap around it. This way I can still clean the glass and use a power head to blow underneath it for cleaning. This will give me a sturdy base and keep the live rock off the glass since we are going glass bottom. You can use reef epoxy to glue your live rock together.

The best advise I can give you is to stay the hell away from live sand. I had it in my 55 gallon reef tank and it was not a good thing. You can clean it and the critters that will help clean it will eventually die from the toxins that live in the sand. I had a beautiful yellow headed sleeper goby that died from sifting through the sand bed and developed black gills. Not only this but it is a place for Nitrates to hide and get it out of control. I had hair algae bad and was having a hard time getting rid of it. We got rid of the live sand and the hair algae cleaned up quickly.

Good luck. Melissa

I put sand first then my rockwork I have it stacked so that it all leans onto the overflows. Not to say I haven't had a rock-slide or two. But never large rocks and never more then one.

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Theres two side to the live sand.. some people have terrible experience others have good. Just beware of the downfalls that some people see so you know how to avoid them or take care of the problems when they occur.

Personally I think a correctly-executed DSB (deep sand bed) is the best form of denitrification available, but some people have different experiences. It's helpful to use a variety of substrate sizes (I use half aragonite, half sand) to keep water flow and a sand bed full of sand sifters (lots of nassarius snails of different sizes) and with a tank your size, maybe a sand-sifting starfish and/or sand-sifting sea cucumber. I always recommend DSBs, but they're not for everyone ::shrugs::

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When in doubt, do a water change.

agreed with the sand sifters. i have a conch in mine and it moves all over.. i also have a flame scallop that likes to blow sand all over the tank. So movement in the sand is definately a plus that way the anerobic areas dont build up too much.

Yeah, conchs are definitely great for that. If I had a bigger tank that would absolutely be one of my first SS critter choices

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When in doubt, do a water change.