High pH from Foam and Concrete Background

[AquaStudent]

I've made a foam and concrete background and currently have it soaking. I've changed the water from the tank quite a few times (on maybe half a dozen or so now). I left it soaking for about 5 hours last night and the pH was back near the top of my High range pH test kit (it's likely that it maxed it out). So the pH is equal to or greater than 8.8.

I don't have a way of testing to see what the actual pH is (if it's greater than 8.8) but am trying to think of better methods to bring the pH down to a more reasonable level.

Like I said, my current method is to fill up the tank with tap water, soak it for a bit, then dump and repeat. It's definitely pulling whatever is causing it out (lime maybe?) but it's hard to tell if it'll be clearing up in the next water change or 1000 water changes from now.

Does anyone have any suggestions/experience?

I was considering using a light acid (vinegar maybe?) to try and neutralize any OH ions that want to come out and play but from what I read about cement is that when underwater it forms sort of an oxidized layer. The oxidized layer protects the internal parts of the cement from erosion and oxidation (and therefore sealing any further leaching). The acid wash would remove any progress towards the oxidized shell that I've made.

 

[Tony]

I've heard of folks doing the initial cure in white vinegar, then switching to regular water. It takes a while, I think.

Is this going in a tank with hard water fish? If not, you may want to consider drying it out and just using a sealer.

 

[Avatar]

Everyhing I've read

Says one must seal concrete for aquaria related use. As it literally takes years for the chemical curing reaction of concrete to be completed, Tony is correct. Dry it, seal it and forget about it.

 

[dogofwar]

Or use Drylok...

Matt

 

[Prince]

The concrete is leaching lime I think. You can either seal the concrete or keep doing water changes till the concrete stops leaching. Probably about a month or two. I can't remember exactly how long it takes.

 

[AquaStudent]

Well as Sam said the concrete won't ever technically completely cure. It is leeching lime I believe. The tank has been dry for a couple of days and I picked up a concrete sealer that I'm going to try to use on it. Hopefully that will work.

The biggest issue is I don't know how high the pH is rising. I tested the water using my API test kit and the High Range pH kit looked nearly maxed out. I took a trip over to my local petco and had them do a water test with their strips just because I could. I believe the strips are generally less accurate than the liquid tests but my water did not max out on their high range pH test (indicated somewhere in the low 8's.

The tank will be for African Cichlids so in theory as long as the pH is not too high they will be ok but I don't want to chance it until I know how high it actually is going.

Does anybody know how high of pH African Cichlids will thrive in (I don't want them stressing). PLEASE DO NOT GO TEST THIS FOR ME

 

[Tony]

If you're tossing rift lake cichlids in there, I'd say give it another few freshwater rinses and go with it. Start with some juveniles in there to make sure they don't go belly-up first though before you add anything too nice.

 

[Prince]

Or some Soda Cichlids.


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[AquaStudent]

I ended up trying some copolymer sealer. I believe it is supposed to be airsprayed onto the surface but I don't have an air sprayer nor would it even fit/get into the tank (since I already have the background in place). So I on Thursday I brushed it on and that seems to have worked. I am not able to get every spot but I got most of the surface area. Today I plan on filling up the tank and seeing how the pH responds.

I'll fill and drain a couple of times and then try a few of the fish in my 55g to see how they do before moving everyone in.

It's harsh but these decisions need to be made to protect the majority. Playing god is tricky...

 

[Avatar]

Just so

Playing god is tricky...

But fun...

"Creative dominion is thine".* — Freshwater Paradigms, Chapter 1, Volume I, Encyclopedia Aquatica

* The corollary to this as is discussed in the venerable text is the converse, i.e., that the Keeper as the arbiter of fate may visit desolation and ruin upon the Kept and so uncreate, either willfully or more often involuntarily.

 

[AquaStudent]

Oh it was only a matter of time before one of the phrases you spoke about in your talk was going to show up

Yes it's very true.

 

[verbal]

any updates

 

[AquaStudent]

The fish are all in there and doing well. I haven't had any deaths in the week or so they have been in there.

So far so good. There are a few patches where the GreatStuff expanding foam I used seemed to have shrunk (not quite sure what would have caused that, getting it wet before it was nearly fully cured perhaps). Anyway that created some weak points behind the cement which caused the cement to flake off.

I have a few patches to fix this summer when I'm home but until then it looks pretty good and is very functional. I will try to get photos up soon.

 

[AquaStudent]

Here are some FTS of the tank a month ago and today. It's quite a big difference!

January 2, 2013

February 2, 2013

 

[Andrewtfw]

That background turned out great! Such a difference from when it just had a black background. Well done!

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