OP
OP
Gregg @ ADP
Valuable Member
Update Pt 1:
Finally got around to rebuilding the collapsed lagoon end. A few challenges with this, primarily being up against the clock. I didn’t have time to tear things down and do a really solid rebuild.
I had 2 hours.
So I’ll try to outline what I did, how I did it, but more importantly, what I did wrong that resulted in this issue.
1. Quikrete Water-Stop Hydraulic Cement:
This product is mildly controversial with reef keepers. Some swear by it, some say avoid it at all cost.
I have used this stuff for years, and let me say first off that I have never had a single issue with it in terms of being an issue with water chemistry. I’ve used it on dozens of tanks, and I’ve never seen organisms react negatively to its use…even without first curing.
That said, this product has some limitations, and there is a learning curve associated with its use and how those limitations in saltwater. It is great for building structures. What it is not great for is supporting load. When using Quikrete, it’s important to not ask it to hold heavier structures together without additional support. If rocks are anchored with dowel or rods, the mortar is excellent in solidifying the structure, even when going horizontally with nothing underneath.
But if you try to get it to bear load, on its own, it will eventually crumble.
The new learning for my learning curve on this one was that plastic mass changes once underwater, and locking everything in tightly with cement when it’s dry, and then not using enough cement while doing so, is a recipe for disaster. When I built that lagoon, not only did I not account for shifting and swelling of the structure, I also mixed the cement too thin. Had there not been any structural shifting, it might have been fine, but all of that shifting plus the weight of all of the sand pretty much just liquefied the cement.
I drained the tank 2/3 of the way down to redo the front corner of that structure:
Once I did that, I realized the cement all the way around the entire structure failed. It opened up against the back panel, and once I moved the sand bed, and bunch of it just slid down under the structure. Womp womp, as the kids would say.
I was able to just cut some filter pad and block it, but I realize now that everything I’m doing is a stop-gap, and after the school year, I’m going to have to drain the tank down and rebuild the lagoon structure properly.
None of the corals I’ve added are attached to permanently cemented rocks, so it will be easy to move all of that stuff out and really get into it.
Despite the relative failure this time, I still really like the Quikrete in reefs. Just need better anticipation next time.
Put back together (for now):
Finally got around to rebuilding the collapsed lagoon end. A few challenges with this, primarily being up against the clock. I didn’t have time to tear things down and do a really solid rebuild.
I had 2 hours.
So I’ll try to outline what I did, how I did it, but more importantly, what I did wrong that resulted in this issue.
1. Quikrete Water-Stop Hydraulic Cement:
This product is mildly controversial with reef keepers. Some swear by it, some say avoid it at all cost.
I have used this stuff for years, and let me say first off that I have never had a single issue with it in terms of being an issue with water chemistry. I’ve used it on dozens of tanks, and I’ve never seen organisms react negatively to its use…even without first curing.
That said, this product has some limitations, and there is a learning curve associated with its use and how those limitations in saltwater. It is great for building structures. What it is not great for is supporting load. When using Quikrete, it’s important to not ask it to hold heavier structures together without additional support. If rocks are anchored with dowel or rods, the mortar is excellent in solidifying the structure, even when going horizontally with nothing underneath.
But if you try to get it to bear load, on its own, it will eventually crumble.
The new learning for my learning curve on this one was that plastic mass changes once underwater, and locking everything in tightly with cement when it’s dry, and then not using enough cement while doing so, is a recipe for disaster. When I built that lagoon, not only did I not account for shifting and swelling of the structure, I also mixed the cement too thin. Had there not been any structural shifting, it might have been fine, but all of that shifting plus the weight of all of the sand pretty much just liquefied the cement.
I drained the tank 2/3 of the way down to redo the front corner of that structure:
Once I did that, I realized the cement all the way around the entire structure failed. It opened up against the back panel, and once I moved the sand bed, and bunch of it just slid down under the structure. Womp womp, as the kids would say.
I was able to just cut some filter pad and block it, but I realize now that everything I’m doing is a stop-gap, and after the school year, I’m going to have to drain the tank down and rebuild the lagoon structure properly.
None of the corals I’ve added are attached to permanently cemented rocks, so it will be easy to move all of that stuff out and really get into it.
Despite the relative failure this time, I still really like the Quikrete in reefs. Just need better anticipation next time.
Put back together (for now):
