Light diffuser under rockwork?

[AZBigJohn]

Getting ready to put rock in the tank. I plan on cementing the rock together (previously I have been a "rock-stacker" but am going for stable). I do plan on having a shallow bed of aragonite sand as well, probably going from 1/2' - 2" in places.

I have always heard it was best to put light diffuser under the rock to stabilize the rock and prevent critters digging the sand out from under your rocks. Just curious what the prevailing logic on that subject is now...

My plan was put diffuser on the bottom of the tank, build my rock structures on the light diffuser, the add my (well-rinsed) aragonite sand.

I do have a Yellow Watchman goby, and will probably add a diamond goby eventually... Will the light diffuser risk injury if they are digging in the sand?

Or, since I am cementing all of the rock, is placing it directly on the glass bottom better?

 

[SnoopyDaPimp]

Put EGG CRATE from Home Depot or Lowes underneath the rock before putting the sand in. That way you will not have to worry about any fish that burrow getting below rocks and potentially making them unstable.

 

[Stolireef]

Only downside is that you might end up with some dead spots in the sand that is in the egg crate.

 

[AZBigJohn]

Snoopy - Thanks. That is the stuff I was calling light diffuser. What do you think is the benefit of using it under the rock? Stability? force distribution over the bottom glass?

Allen - I agree. And the risk of having "overblown" spots where the egg crate is visible...

I am slowly start to lean towards rock on the bottom, cemented together, and then sand around it, so anything digging down will not make rock unstable (sitting on the bottom) but then there is no plastic in the sand to potentially injure a digging wrasse or goby.

 

[Stolireef]

I am slowly start to lean towards rock on the bottom, cemented together, and then sand around it, so anything digging down will not make rock unstable (sitting on the bottom) but then there is no plastic in the sand to potentially injure a digging wrasse or goby.

That's what I did in the past and never had any issues.

 

[juniorrocketdad]

I used starboard underneath my rocks, if you silicone it to the bottom there is no risk of dead spots