<a href=showthread.php?s=&postid=9022037#post9022037 target=_blank>Originally posted</a> by rufio173
Bad results happen when you cut too many corners and try to save too much money, so it can't always be blamed on the rock, but the reefer.
In a thread like this, if a lot of people weren't having/didn't have some algae issues, they would be speaking up, vociferously. :bounce2:
So far, like only Trout (and a few others too) has said he didn't have problems, and also explained that his rocks were cured in a river.
Ever seen fresh poured (2 or 3 years old or less) cement in a pond or river? Like pilings or ramps? And it is covered with algae, yet the rocks nearby are not? Wonder why?
Lime, one of the components of cement is a FERTILIZER. The rocks we make are BIG BALLS of FERTILIZER, especially in the first months of their creation. I don't know about the other components of cement, but I know Lime grows Grass and Plants.
My very first batch that I made, like 7 years ago was for a shroom tank. The tank was doing great, had been up and running for like 6 months at that point, had an algae outbreak during like month 2, but it went away on its own. SO no algae to speak of and I added 2 pieces that had cured for 3 months. Within a week, I had green splotches of algae covering the new rock. Not anything else at that point. Within 3 weeks, I had hair algae in tufts, spreading out from the rocks, starting to grow on things more heavily that either were the rocks, or close to the rocks. A month later I bought a pair of queen conchs and a lawnmower blenny (They are so fun!), and after like 3 months, I had no more algae problems, and coralline started to take root. In 6 months, my rocks were covering readily in good stuff and my problems were over.
I for one understand this about the rock, and accept it as the "cost" of using DIY rock. But on the up side, I get shapes that I could never hope to purchase, have a lot of fun making it, and know in my heart that I, in this instance, didn't contribute to stripping our reefs.
Those who want to use DIY need to realize that this will probably happen to you too unless you can kure the rock in a free flowing waterway. And realize that it isn't a disaster, and that it will go away once the easily extracted nutrients are used up.
If you can't kure in a waterway, and are really concerned with algae, you might try introducing some algae to the kuring tank/bucket after it is done kuring, and let the algae do what it wants for a while.
Either that or buy your man made rock from the pros, who's rock is well kured for 6-12 months usually, often in the ocean, and then seeded in the ocean or tanks - but that stuff costs as much as good real rock.
I know it may seem like I am crazed, but saying that this rock won't cause algae blooms, or that it
has to be something else is just plain irresponsible. I agree that often people do cut corners, or are lazy and this causes problems a lot too, but if the problem in the tank is algae, and you are using DIY rock that you made, and other things were ok before the rock was added, chances are good that the cement is responsible, and that time will cure the algae.
I saw the beginning of the paragraph talking about Portland cement and I jumped the gun. 
Looks great man. Looks like you saved a few bucks on the rock and ended with an amazing result!
