Muriatic Acid

Lukara

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Jan 13, 2003
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Hi :) Just a quick question. It is recommended to test rocks with Muriatic Acid. Is it still safe to put the rocks that have been tested with this into the aquarium even after they have been thoroughly rinsed with water?
 
Rinse, rinse, rinse and you should be fine. It is a very strong acid (take care when using it) but enough rinses will dilute it to a non harmful level.
 
Muriatic acid is also called hydrochloric acid. And a few drops of this acid on a rock is not going to affect an aquarium in the slightest even if you don't wash it off. It would have to be a really small tank (say one gallon) for it alter water chemistry. So I would not worry about it. It's not even poisonous.
 
I don't know where you get your acid but I am 100 % sure that it is poisonous. I use it in my work and must wear protective gloves as well as a mask.

It states right on the bottle that swallowing may cause blindness. Damage can even be done by the fumes.

Please check but I think that you can you regular vinegar to do the "acid" test on the rocks.
 
Just for info: Muriatic Acid is commonly used by fish breeders for acidifying the water beyond what RO/DI units can do. It is potent and you should test frequently when using it for making water more acid. It also adds Phosphate (phosphoric acid), if I'm not mistaken, so it can wreak havoc due to algae problems, but if used properly is quite a standard practice for fish husbandry techniques. For more opinions you can check out Apistogramma.com. Many of the members have used it with success.

For the rock-acid test, it's easiest to use venegar, but I agree with RustyRay for the most part, but I'd rinse the rock afterwards if I was using a 20 gal tank or smaller, just to be safe. Much of whether or not it will alter your water is dependent upon how well buffered your water is (KH). If you have hard water, probably nothing noticeable will happen without adding many drops, but each drop uses up some of the buffering. I don't know exact formulas, just the basic theory.;)
 
The salt used to make seawater is caustic and potentially dangerous when inhaled, but once added to water it is harmless. The same goes for a little acid.

Muriatic acid is, of course, dangerous when it is undiluted. And the fumes are harmful if one is exposed to them to much. But a few drops on a rock is not going to posion an aquarium or harm anyone.
 
Thanks for your responses all. I mean to put the rocks which I intend to test in a 50 gal tank. I will try testing the same rock which I know is supposed to foam, with both muriatic acid and white vinegar to see if I get the same response from both forms of acid and if so I'll use vinegar to do my testing. It's because I was led to believe that using muriatic acid is more reliable due to it being a stronger acid, but if I get the same results with both, then I'll use the safer of the two.
 
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I tried vinegar and in some cases it simply doesn't show much visible reaction to determine if the rock has any calcium carbonate in it. I thought many of the rocks I have in the aquarium are "safe" since they passed the vinegar test, but when I read about using the #1 bottle of ammonia test (apparently also HCl), I tried and half of what I have in the tank was bubbling! I took some out and left some in since my water is super soft, but that goes to show that vinegar may not catch all rocks.

HCl, when diluted, should be very safe for aquariums... (or even for human for that matter).
 
I have access to lots of acids at work and I agree that acetic acid tends to miss a lot of rocks. The muriatic was one of the best (so is sulphuric).
 
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