Aquscaping with portland cement rock

[woodenfish]

Can one use portland cement to make rock and use in a discus tank after extensive curing?

Say if I use type I-II portand cement, one part cement to three or four part sand, to make rock work, can I use it in my discus tank after curing? Would such rock be forever too alkaline for discus tanks?

Curing would be a process that takes a couple of weeks. I would place the rock work in a plastic container and change the water frequently. May be I'll add an acid so that the ph would be 5-6 to start.

I have seen a couple of pictures of apparently concrete-like blocks in a discus tank.

I don't know how cured portland cement will affect the ph of a discus tank even after a couple of weeks of curing. Or would longer period of curing or some other method of curing help?

Thank you.

[RandalB]

This is common in reef tanks, but you'll need to cure longer than a couple of weeks. I've heard of it taking several months to get the pH below 12...

RandalB

[midazolam]

I've read of a lot of people using quikrete quickwall (you can get it on special order from home depot or lowes). It is EPA or FDA or FBI or something approved for using in livestock tanks (moo). From the stuff I've read you let it cure dry for about 3 days (keeping it moist w/frequent sprayings), then stick it in salt water for about 3 days. Flush the tank, add tap water for three days. Then repeat two or three more times and usually you're back to normal. I'm 1 day into the dry phase of curing. So about 3 weeks start to finish.

[tonymaccs]

From my experience with concrete tanks made from portland cement, you could be fighting heavily buffered alkalinity for many years to come. Perhaps there are some sealers safe for potable water that will keep the cement from efflorescing or lime leaching.

[woodenfish]

I've read of a lot of people using quikrete quickwall (you can get it on special order from home depot or lowes). It is EPA or FDA or FBI or something approved for using in livestock tanks (moo). From the stuff I've read you let it cure dry for about 3 days (keeping it moist w/frequent sprayings), then stick it in salt water for about 3 days. Flush the tank, add tap water for three days. Then repeat two or three more times and usually you're back to normal. I'm 1 day into the dry phase of curing. So about 3 weeks start to finish.

Please let me know how your project went.

I suppose Quikrete Quickwall is special and does not leech out alkaline material after only three days in salt water.

[woodenfish]

I found out the Quikwall is still a portland cement based product.

I don't know how it can be cured with salt water for just three days and become discus-safe.

May be it is because the application is with just a thin layer of the stuff, in comparison to inches of portland cement.

[midazolam]

I found out the Quikwall is still a portland cement based product.

I don't know how it can be cured with salt water for just three days and become discus-safe.

May be it is because the application is with just a thin layer of the stuff, in comparison to inches of portland cement.

its a cure 3 days w/salt water, 3 w/fresh, 3 w/salt, 3 w/fresh, 3 w/salt, then three with fresh routine. So 18 days I've been told. I've completed one full day of salt water curing. I'll let you know what my pH is at the end of fresh day 1 and day 3. My pH is 8.0 to 8.2 depending on the time of day from the tap :(

[Don Trinko]

A good test when you think it's done would be to fill with RO water and test TDS for a few days. If the TDS stays low I think it would be OK. Don T.

[midazolam]

my pH was stable last sunday. So it took about two weeks. I'm going to continue 3 days of salt 3 days of fresh until this saturday to be safer.

Please know my pH out of the tap after 24 hours of again is 8.2. I don't know if it would take longer if curing in softer water.