Cement use in FOWLR tanks
 

Anyone have experience using cement in a tank? I have heard they will cause chronically high pH? will this taper off over time?
I am trying to make a wall for the back of my 30Gal Hex and am contemplating using cement with embedded LR. (LR will die during construction i know)

thoughts?

from what i know you have to let your cement that you have made soak in water with frequent water changed (ie back of toilet, depending on how big it is) in order to help leach out all of the extra stuff. Just what ive heard no personal experience.

any other takers?

I'm in the process of locating some Thorite cement. No pH spike, can be used in the tank right away. Theoretically, any polymer based patching mortar ought to be the same situation, but Thorite has a proven history to be safe in aquaria.

Regular (Portland) cement is OK, but you have to cure it properly, for example keep the rock in a toilet tank (if small enough) for 6 to 8 weeks.

Bear in mind when I say "it's OK" you still have to be careful. Have heard a few stories with people having their chemistry thrown off for upwards of a year or more because they did something off with their DIY rock. In a FOWLR it may be less of a concern but even fish can be stressed out by wacky params so it's still important to proceed with caution.

Hey Tony, if you ever find that Thorite, please post where you got it. Inquiring minds want to know :biggrin:

The short answer is it's not available locally in Calgary. There are substitutes that look like they ought to be OK though. So, the question is, take a calculated risk with one of those, or maybe do a group order from that one site that does mail-order? I'd hate to think what shipping will be like though.

Here's the link (you can't order online though, have to call).
http://www.chargar.com/Products/prod_mf.html

What do you think, should we do a group order maybe???

I used white cement when I made my rock walls. I dont remember the brand but I could look tomorrow.

I mixed it roughly 1to4 with arganite sand. Poured it into the precut eggcrate form and let it set for a couple of days. Since the tank was empty I put it in where I wanted it and let the tank run for 6 weeks with fresh water ,changing the water as often as every day when I thought about it and every 3 days at the max.
Roughly 20 gallon tank with 2 walls (16x16) of the cement. The PH would go up within a couple of hours to 12-14! After 6 weeks it would hold pretty steady at 8 so I ran it for a couple more days with some vinegar added. After that I ran it with saltwater umm for a week or so adding vinegar.

Emptyed it out, refilled it and added some mushrooms and 2 small chromis.. then the algae started! It was a cesspool for at least a month.. then suddenly all the algae was gone and coraline was growing.

I have 2 deepwater anthias and a seahorse in that tank and havent had a bit of problem with ph.

If you want more details on how I poured the walls and formed them send me a PM.