limestone Rock in the aquariam

  • #1
hi, a friend who's giving up fishkeeping gave me all his Limestone rock,I got told it keeps the water clean.
But it even makes the water hardness higher I want to put it all in my 35 gallon tank, what does Limestone rock really do?
  • #2
Raises hardness and pH of the water. Provides surface space for good bacteria, but no it does not clean the water.
  • #3
Limestone rock is not good for a freshwater tank. It can raise your pH too much. Your tank is freshwater, right?
  • #4
I must disagree, it depends on the buffering power of your water, dissolved mineral content, if you have liquid rock like the Tennessee Valley does, limestone in the tank makes little difference. Buffering power has to do with ions and kinda tied to hardness, and gets more chemically complex than is worthwhile to try to explain.

A friend of ours that has snowmelt for water, yeah that would present him with problems. He has to keep crushed coral in most of his freshwater tanks just for buffering capacity, whereas we have almost liquid rock.

Basically buffering, in easy terms though is:

If you have chemically neutral water (not hard not soft, but centered), a drop of acid would drop it, a drop of heavy mineral water would raise it. If you have hard water like we do it takes more drops of minerally heavy water to affect the hardness as much as it would for acid water or neutral water, if that makes sense.

But toying with the pH of the water is like toying with a human's oxygen supply, very risky, very tricky, and should be kinda left to people who are used to doing that successfully, in my opinion.

(toying with water is easier in large bodies of water, versus glass boxes. large, ie. ponds, lakes, rivers, oceans.)
  • #5
Chief, you may be right since I am not a water chemistry expert. But I have read and heard that any calcerous rock isn't good for a freshwater tank. Limestone rock is calcerous. Hence my comment This kind of rock could be OK for some African Rift Lake aquarium, but I am really not sure about a regular community freshwater tank, you know. But like I said, I can't comment further on that since I am not qualified enough (in terms of the more sophisticated water chemistry) to do this.

Though I certainly agree that messing with pH is not a good idea.
  • #6
I agree a large number of aquarium fish do not need to be kept with limestone rock. Fish from the Amazon river system of South America, the majority of the fish in the hobby from southeast Asia, and those from the jungal regions from the west coast of Africa, to name a few, would find conditions created by having limestone in the water as detramental. On the flip side, just about any livebearer, fish from Mexico and Central America, and Isabella was absolutely right in that East African Rift fishes would all thrive in tanks with limestone.
  • #7
Ok playing devils advocate here
Since the limestone dissolving is what raises the pH(is that correct?) wouldn't it happen so slowly that the fish would adjust to the rising pH? Usually it only raises it a couple of tenths of a degree. When I had Texas Holey rock in the tanks my water went from7.4 to 7.6 or 8 but it took months for that to happen. but definitely didn't keep the tank any cleaner nor dirtier Just curious.
fizzypopz- what are you planing to keep in the tank?
  • #8
Thank you Carol for your help Chief, if Carol says it's OK, then it's OK, lol I personally never had any rocks with a lot of calcium in any of my tanks so I wouldn't know. All I know is that rocks containing a lot of calcium are generally not recommended for freshwater community tanks. But if limestone rock and Texas Holey rock are this slow to act, then of course no problems there because there are no sudden pH spikes. As long as fish are not subjected to sudden pH spikes or drops, all should be OK.
  • #9
Limestone's ok.

As Carol stated, it changes the water so slowly, the fish have no problems with it.

I have dozen of tanks with limestone here and it does not chane the 7.6-7.8 water I have out of the tap.

As also stated, fish from certain regions would be better off without limestone.

And in other situations, I know of folks who have to have crushed coral or limestone to keep their water from being too soft for fish, ie snow melt water source in the rocky mountains.

Most of the fish raised in Florida fish farms are in water that comes from wells drilled in fossilized coral, which gives the water a pH of 7.6-7.8 .
  • Thread Starter
  • #10
thanx everyone for your replies this has helped a lot.

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