Whats Wrong with Normal Concrete?

[dartman]

I have read on this board about Habbacrete. What is so special about this product that makes it different from regular concrete? What are the drawbacks to using regular concrete? Is it the portland cement and if so, is portland toxic when set? Thanks for your time.

[captaincarot]

portland leaches high ph hardness into any water that gets onto it.
so if you put the water in an enclosed space it will eventually become caustic.

[Green Ghost]

Anyone know how to cure cement? Meaning make it Neutral (Ph 7.0)?
I've heard it can be done by rinsing repeatedly with vinegar.

Was hoping for more specific directions from someone in the know....

[bmbeyond]

I've read the same thing about vinegar. never tried it myself but I've read that you are supposed to soak the cement in a water and vinegar solution. If my memory doesn't fail me the cement will foam up untill the the ph level is at a neutral state.

Don't quote me on the last part. I would google "how neutralize cements ph with vinegar" or something to that effect before trying it.

[Green Ghost]

Sounds like a plan. When I'm finished building this small waterfall, I'll try to cure it using the vinegar and post my results.

[icytea_thunder]

Yea, the issue with cement is the fact that it buffers the water to a higher pH. I had recently made a cement background for my African cichlid tank (Here) and had to soak the water constantly with 4-5 total water changes till the pH equalized. Vinegar, since it is acidic, will hasten the loss of buffering capacity of the cement in your vivs, you'll just need to keep an eye on it. It probably is the most important part of the construction process.