Concrete raise pH?

[ejmeier]

I have been checking out a european site on ideas for backgrounds, and one of them caught my interest.

You carve a background out of styrofoam and then paint on a layer of concrete and let it dry. It looks pretty cool, the only thing is that the concrete contains limestone (I think? ) and raises the pH of the tank a decent amount.

Can anyone affirm this pH raise, and if so, by how much? I looked into the pH range tolerances of my fish, and they look like they could handle an increase from 7 to about 8. Anything above 8 would be pushing it...

Inhabitants are:
1 x Tiger Oscar
2 x Gold Gouramis
3 x Clown Loaches

Thanks

 

[ChilDawg]

I'm not so sure that Clown Loaches could take a 10-fold increase in pH that well.

 

[ejmeier]

It's not like it's gonna be an overnight change from 7 to 8 in the tank. I would acclimate them to the new water conditions slowly.

Anyway, my source for this is wetwebmedia.com , which lists the clown loach as having a tolerance range from 5 - 8. Pretty wide margin of error for pH IMO.

 

[ChilDawg]

I thought that you were talking about an overnight change...if it's gradual, they'll be okay!

 

[wetmanNY]

What if you painted it with epoxy, grayish streaked with tan, then scattered dry sand on it while it was still tacky? Wouldn't you get a similar look?

 

[momopoms]

Is styrofoam safe?

If you could get away with the concrete, is the styrofoam safe for tanks? also, isn't lime in the mix too? just wondering.

 

[ChilDawg]

Styrofoam is safe...many foam backings are sold commercially for just such a purpose.

 

[Hebdizzle]

concrete CANNOT BE PUT INTO A TANK until it is cured. It can cause a PH of over 9! It must be cured in freshwater for 5 to 6 weeks, with water changes every week. It contains a high amount of lime which easily leach into your aquarium!

I will find a link to prove.

Aaron

 

[Matak]

Don't do it!

Concrete, like brick mortar has many more additives than just portland cement, lime, sand and stone that can leach out and are poisonous to fish. Last winter (before I learned about proper fishkeeping) I put in a brick & mortar cave for decoration. My fish began to really get stressed & sick. I lost a couple before I pinned down the source of the problem.

Styrofoam is OK and using a hot knife creatively can give you some really neat effects. You'l have to find a paint that isn't harmfull to fish or styrofoam.

Good luck

 

[ejmeier]

Sorry abuot the confusion guys, I was intending to use PORTLAND CEMENT. I know that concrete is probably bad for the tank, but the portland cement is practically harmless.

It DOES need to be cured however. It contains something that I think is limestone-type that raises your pH.

You see, I have a reef background, and I have read all about make rocks out of sand, crushed coral and portland cement. It works great, but you do have to cure it to prevent pH swings...

Hebdizzle: here is one such link of probably dozens if not hundreds more that are out there showing the pH raise in cement: http://reefcentral.com/forums/showthread.php?s=&threadid=60515

wetmanNY - epoxy is too expensive for my budget. A $5 sheet of styrofoam and a $5 bag of portland cement, and I'm ready!