How stable the rocks must be?

[nuxx]

Some rocks do better than others with no adhesives / rods.

We used acid washed Marco Rocks and they really stuck together very well, very sharp.

We have some very active tangs and triggers in the tank and lots of flow. I'm not really worried about them falling over.

Had intended to use epoxy and rods, but never needed to.

 

[afoifa]

Ive always used milliput epoxy putty, worked well for me so far even in my tropical tank with a very destructive blood parrot the headbutted rocks to where he wanted them,

I noticed someone else saying acrylic rods, i would probably go with this or both once my predator tank is ready

 

[Flippers4pups]

was there any particular brand or type of hydraulic cement that you used? any particular additives to avoid?

Quickcrete, there's a post by "Mr.wilson" on here, something like "reef ceramics", that he has used for years and has had no problems.

 

[MondoBongo]

Thanks!

 

[MondoBongo]

so just to be explicit, i found the other thread and ended up buying some of this from Lowe's:

http://www.quikrete.com/ProductLines/HydraulicWaterStopCementPro.asp

QUIKRETE® Hydraulic Water-Stop Cement (no. 1126) is a rapid setting, high strength repair material designed to plug leaks instantly in concrete and masonry. Sets in 3-5 minutes and can be used above and below grade.
Designed to block running water or leaks in cracked masonry or concrete surfaces.

here is the link to the original discussion:

http://www.reefcentral.com/forums/showthread.php?t=993625

originally i had ordered some of the reef cement from marco rocks, but they took almost two weeks to ship it (it's still not here) and it costs ridiculously more than the Quikrete (over 6 times as much).

 

[Flippers4pups]

Yes, that's it. It sets quickly, in less than five minutes. So you have to work with it quickly and in small batches. Don't skimp on the amount you apply because it could crack if too thin. I used fiberglass rods with my rock as well to strengthen the stack of rocks and for the overhangs. It's been under saltwater now for two months with no spike in PH. The only downside I can find is that it's dark, but that will hide once coralline takes over.

 

[Flippers4pups]

Here's before it got wet:

 

[mmittlesteadt]

so just to be explicit, i found the other thread and ended up buying some of this from Lowe's:

http://www.quikrete.com/ProductLines/HydraulicWaterStopCementPro.asp



here is the link to the original discussion:

http://www.reefcentral.com/forums/showthread.php?t=993625

originally i had ordered some of the reef cement from marco rocks, but they took almost two weeks to ship it (it's still not here) and it costs ridiculously more than the Quikrete (over 6 times as much).

While there has been many words of warning over using hydraulic cement, none have come from those with first hand working knowledge of its use or effects. But, there are many (myself included) who have used it with great success and no ill effects on life in the tank.

And also, keep in mind Marco does not declare the ingredients of their "magic" bonding cement. They only say its reef safe (as are other hydraulic cements). I doubt they've stumbled upon some new discovery in gluing rocks together, and I can only assume it's the same thing, but simply re-branded.

And that's fine with me...I'm not knocking them for doing it because I think its great that they do.

I just think there are cheaper alternatives that are just as safe.

 

[MondoBongo]

That was my feeling as well. When things get packaged with the term "reef safe" the cost tends to inflate dramatically.

I don't blame them either. In a lot of cases it makes sense because before I stumbled on this thread I didn't even know what hydraulic cement was.

My order from them finally came today, it's waiting at home me. So I'll get to compare it to what I picked up at Lowe's and see if it is similar.

 

[ca1ore]

I place the rocks onto the bottom of the tank, not onto the sand. Not sensitive to sand burrowing animals as a result. I then stack the rocks so that they are stable. A few chunks of the D&D epoxy putty and there's no unwanted movement. Can be disassembled as needed with just a bit of elbow grease. Only exception are the rocks that cover one of my overflows. In that case I used zip ties and a few strategically located holes in the rocks.

 

[Bruce51]

I am going to use acrylic dowels with no epoxy http://www.estreetplastics.com/
cutting bottom of base rocks flat to sit on glass then dowels to thread pieces together.
That way I can easily disassemble if I have to when tank is up and running

 

[Flippers4pups]

That was my feeling as well. When things get packaged with the term "reef safe" the cost tends to inflate dramatically.

I don't blame them either. In a lot of cases it makes sense because before I stumbled on this thread I didn't even know what hydraulic cement was.

My order from them finally came today, it's waiting at home me. So I'll get to compare it to what I picked up at Lowe's and see if it is similar.

Well that's what I came across with my Marco rock. Everyone I spoke to told me "your going to have phosphates leaching from them". Had me scared to go that route. But I did my research and read as much as I could about it from now going back to around 2008. Found that the rock people where getting back then looked "solid" and not as porous looking as now. Back then everyone was having Po4 issues from the rock. Marco changed locations from where they where mining the rock and started cleaning it. I assume acid baths and thoroughly rinsing them.

The rock I got from them this year looked very white and very porous. I even placed it in saltwater for three weeks and tested every other day for Po4 and never go any positives.