DIY Background Concrete Curing Time

[DogWalker]

Decided to create a background for my new 150 that is removable. To do this I used sheets of acryllic as a 1st layer, onto which I silliconed styrofoam. I then carved out the relief in the styrofoam. Next I hollowed out the styrofoam everywhere I could and filled it in with concrete in order to offset the buoyancy of the remaining styrofoam. I then proceeded to the concrete coating and colouring stages (w/ concrete pigment).

I'm quite satisfied with the results look-wise, and the 3 modules are pretty close to neutrally buoyant. Just one rock at the base of each holds them in place along with a pair of ABS pipe clips at the top (cut a 1.5" length piece of ABS/PVC pipe and cut out a 5/8" gap lengthwise - it fits over the rim of the tank and holds the top of the background in place perfectly).

The only drawback to this approach so far is that the concrete seems to be taking a long time to cure, probably due to the amount required for this technique. Nearly a month of emptying and filling the tank every 3 days and the concrete still raises PH too much (0.5 in 3 days) for me consider starting to cycle the tank.

Not sure if anyone else has done anything similar and can provide any insight into how long it will take. If so I welcome news of your experience...

[RustyNut]

You could just epoxy coat the concrete and save yourself the whole curing process....

I tried to do one a while back but Iwasn't happy with my results so I never got to the curing stage... However I have read 6-8 weeks is normal.

[DogWalker]

Hello Rusty! Yes, I considered the epoxy and did spend quite some time researching and looking for aquarium-safe 2-stage epoxy products. The only ones I found within a hundred mile radius turned out to be available only 1 mile from my house! Only problem is they're expensive. Would've cost me something like $100 US just to try it out, without knowing the outcome in advance.

There are a lot of marine (ie: boat) products available, but they all seem to contain 'anti-fouling' (= anti-fish, anti-algae?) agents. Some people will probably say they've used them OK but I didnt want to risk it.

6-8 weeks - hmm I hope so. The way its going I'm worried it could be double that. Oh well, let this thread serve as an example of the pros and cons of doing it this way. The pros are, I didn't stick anything to the glass and can lift this background out anytime I'm tired of it without emptying the tank... Plus I have a layman's peace of mind in knowing it is not creating any stress points on the glass and exerts virtually no force (upwards or downwards) on the tank. Despite the wait I'm still betting I'll end up being glad I went this route.

Thanks for the feedback.

[RustyNut]

Just curious, you're using salt-water to cure with right? Its supposed to speed up the process....

[Exister]

Mine took about 7 weeks. I used water softener salt, but I'm not sure how much it really helped.

I read somewhere that the key is water actually rinsing over the concrete. Some guy over at the cichlid-forum site said his cured REALLY fast when he left it out in the rain, with the water constantly flowing over the concrete.

Does that make sense? I hope I explained it well enough.

Mine was cured "in place" in the tank, and I thought it would NEVER cure. You'll get there! :)

[DogWalker]

Salt? no, I hadn't read anywhere that that was part of it. Maybe I missed comething obvious here - I guess I should look into that further.

I have been running an AC 500 without any media as well as a (rather weak) power head to get some circulation; nothing like torrential rain, but where would you find that 7/24 anyways? (somehow I don't think torrential snow will have quite the same effect. :xmas5:)

I will try salt - nothing to lose I suppose.

Thanks!

[DogWalker]

Oops. smiley should have been :xmas5:

[Exister]

Just make sure you get the water softener salt without any extra chemicals.

This is what I used (got it at Home Depot): http://www.mortonsalt.com/consumer/products/watersoftening/white_crystal_ss.htm

[DogWalker]

Exister, thanks for the link. I got an equivalent product from an equivalent store. Way cheaper than buying aquarium salt to do this! I'm putting it in the outflow compartment of the AC500 to dissolve it as there is no media in it at the moment. Not sure how much is needed - I assume I can just keep adding it as long as it dissolves.

[DogWalker]

Out of a 44lb bag I've added 10 lbs. It's raised the specific gravity of the water to around 1.008 or so. Base on that it sounds like I would need to add something like 120 lbs of salt to raise the salinity to near seawater levels. That's probably more than necessary to accelerate curing. If I add half the bag (ie: another 12 lbs) the sg should be just under 1.020. Will that be enough?

[Exister]

I would imagine so, but I'm no expert. I used my 40 lb bag 20 lbs at a time. Just get used to doing a ton of water changes, even after doing the salt thing. :)

[DogWalker]

The water changes are no big deal. The tank is in a room next to the garage, which has a large floor drain, so I can use a hose to empty and fill the tank without lifting a bucket. I've threaded the hose through some ABS pipes and elbows so I can just hang it over the side of the tank and go do other stuff for the 45 minutes it takes to empty and 20 to refill...

It's the waiting that's driving me nuts - kind of like getting a new car 3 months before you're old enough to drive!

[DogWalker]

Well, my cycling crew is FINALLY in the tank. The PH is still rising a bit, but no so much that regular water maintenance won't control it.

From the above suggestions, I've found 2 things for certain. I won't drag it out recounting the whole experience, but in summary:

1. Salt DOES make a difference - sends the PH off the chart real quick, which tells you it's doing something. (Thanks for that, Rusty & Exister).
2. Spending some time rinsing water over the background instead of just filling the tank and letting some equipment run also speeds things up (thanks again Exister).

6 juvie yellow labs are now in the 18g quarantine tank! (Starting with those as it'll give me another month to make up my mind on the rest of the stocking list...)

[DogWalker]

Seems the conrete is STILL raising the PH a bit, but again, nothing a 25% weekly water change doesn't keep in check.

I'm wondering if this means there is still some chemistry happening that could be harmful to the fish however? I moved the 6 yellow labs into the tank (they were in the quarantine tank for over a week first), and shortly thereafter some of them stopped eating. Classic early symptoms of bloat - ie: not eating and being somewhat reclusive. But its been, like, 10 days now and none of them are showing any further symptoms (except the runt - it died). No swelling, no stringy white poop, etc. Their swimming form is a little unsteady at times, but just noticeably.

I am starting to treat today with Jungle Parasite Clear which contains Metradizanole (probably spelled it wrong) as I am assuming it is bloat, but the cause of it escapes me - water parameters are great (amonia, nitrite, nitrate all 0, temp 78F, PH varying between 7.9 and 8.2 weekly because of the aforementionned effect of the concrete).

Could the tail end of the concrete curing be causing this, or am I right in guessing bloat?

PS: I was feeding several 1-minute meals a day of NLS and goldfish food until they stopped eating. I did feed them 3 meals of a Tetra-min product labelled 'Spirulina Flake' until I checked the ingredients and found Spirulina to be somewhat down the ingredient list, and '48% protein' - somehow I'd doubt that's the cause though?

PS-PS: I also added 5 Acei over a week ago. So far they're still eating and even showing some breeding behavior. (I am keeping a close eye on them.) That, plus the labs didn't all stop eating at once, sort of argues against toxins from the concrete being the cause... What do you think?

[DogWalker]

As this latest of my endless inquiries spills into the 'Cichlid Health' category I decided to post this problem there. Please reply to that thread instead of this one. Many thanks.