FrontyKing Posted February 27, 2006 Share Posted February 27, 2006 Hello guys, I bought some black gravel to use as substrate on the weekend from a LFS, but before doing so I was tossing up between that and sand. Once I found out that sand will more than likely raise my PH, I asked about the gravel and was told that it won't raise the PH. This substrate is intended for a catfish only tank, hence the reason why I want to keep the PH down. I brought the gravel home and got stuck into cleaning it out straight away. After cleaning it for about an hour(only 7 or 8 kilos of it) when you couldn't get it any cleaner, I started cleaning it again just to make sure that it was clean. With that out of the way, I think I have ruled out any possibility of it not being cleaned enough to keep my PH up at 8.0-8.1 when I need it to be around 7.0-7.2. I used Ph down that afternoon to get it down to 7.5. When I checked it this morning it was back at 8.1. I gave it another hit of PH down and got it to 7.5 and again this afternoon when I got home I found it at 8.1 again. In the tank there are also 2 half pots(9 inch ones) and a medium piece of bogwood(about 1/2ft long and 1/2ft wide with anubis growing on it. I don't want to drop the PH quickly as I'm worried I might shock the fish that are in there. Is it the black gravel or is it something else? Water parameters are ammonia, nitrite, nitrate = 0 Any ideas guys? Thanks, Nick. Link to comment Share on other sites More sharing options...
Ash Posted February 27, 2006 Share Posted February 27, 2006 I used to have black gravel & it did buffer slightly, though the pH stayed at about 7.6 compared to a tank with different gravel or river sand which stayed at 7.2-7.4 with my tap water. What's the hardness of your water out the tap? Link to comment Share on other sites More sharing options...
FrontyKing Posted February 27, 2006 Author Share Posted February 27, 2006 From the tap it's at 7.6 Link to comment Share on other sites More sharing options...
Markus13 Posted February 27, 2006 Share Posted February 27, 2006 If you use Pool Filter grade sand it wont affect your pH in any way at all. Black gravel shouldnt affect it either Link to comment Share on other sites More sharing options...
FrontyKing Posted February 28, 2006 Author Share Posted February 28, 2006 Problem solved guys, it is the gravel. I covered some gravel in a cup with some vinegar and low and behold....BUBBLES. The gravel contains calcium so therefore it raises the PH. I won't be taking advice from that LFS anymore, you know who you are! Any other recommendations on substrate? Pebbles maybe? Cheers and thanks guys for all your input! Nick. Link to comment Share on other sites More sharing options...
wormboy Posted February 28, 2006 Share Posted February 28, 2006 I think it may be what is attached to the calcium that is causing the problem (carbonate) rather than the calcium itself, either way it is still the gravel . BTW nice thinking dredging through the old chemistry brain archives to find the acid+carbonate=CO2 reaction. -Mat- Link to comment Share on other sites More sharing options...
Timah Posted March 7, 2006 Share Posted March 7, 2006 Is it just that type of Black Gravel? I want Black gravel too but i don't want it messing with the pH. Surely there is more than one type of black gravel? One that doesn't raise the pH? Link to comment Share on other sites More sharing options...
Ash Posted March 7, 2006 Share Posted March 7, 2006 Timah - Get a small sample of whatever you plan to use & test it with vinegar as FrontyKing did above. I'm sure not all black gravel buffers Link to comment Share on other sites More sharing options...
Josh Posted March 7, 2006 Share Posted March 7, 2006 I dont think it would the colour of the gravel but what stone it is from, that would dictate, whether or not it buffers the water Link to comment Share on other sites More sharing options...
Timah Posted March 7, 2006 Share Posted March 7, 2006 I dont think it would the colour of the gravel but what stone it is from, that would dictate, whether or not it buffers the water ← Yeah but its the type that dictates the colour. thats what i'm asking is there only one type of the gravel. Ash, How would i go about taking a small sample? Link to comment Share on other sites More sharing options...
FrontyKing Posted March 7, 2006 Author Share Posted March 7, 2006 Timah - Get a small sample of whatever you plan to use & test it with vinegar as FrontyKing did above. I'm sure not all black gravel buffers ← I dont think it would the colour of the gravel but what stone it is from, that would dictate, whether or not it buffers the water ← As both Ash and Josh said, not all black gravel buffers as I have found. Keep testing like i did with vinegar and you'll find one that doesn't. HTH Nick. Link to comment Share on other sites More sharing options...
D6C1 Posted March 7, 2006 Share Posted March 7, 2006 I've been thinking of changing to black gravel too on my display african tank. Anyone with pics of black gravel tanks? How is yours now Nick? Link to comment Share on other sites More sharing options...
mianos Posted March 7, 2006 Share Posted March 7, 2006 My black gravel does not ffect my pH at all. Link to comment Share on other sites More sharing options...
FrontyKing Posted March 8, 2006 Author Share Posted March 8, 2006 The one I have found is exactly like mianos' Link to comment Share on other sites More sharing options...
Timah Posted March 10, 2006 Share Posted March 10, 2006 and thats the one not affecting pH? there is some stuff at one of the LFS and it says "would not affect pH" but i'm not too believing because "would" doesn't seem too positive. Does the size of the gravel make much of a difference to gavel vacuuming? i know sand does but thats sand... Link to comment Share on other sites More sharing options...
FrontyKing Posted March 10, 2006 Author Share Posted March 10, 2006 Yeah that's the one not affecting ph. Smaller gravel pieces get uplifted with the gravel vacuum easier, therefore your cleaning will be quicker. Nick. Link to comment Share on other sites More sharing options...
Ash Posted March 10, 2006 Share Posted March 10, 2006 The stuff I've got that only slightly affects the water looks very similar to that pic posted by mianos - I am about 2000km away so its not likely to be the same stuff but you never know. Unless you're keeping blackwater fish I'm sure you'll be alright, but if you're really worried, get a little bit & test it! As to grain size - the smaller the size the less waste will fall into it. I've found mulm sits on the surface a lot easier to vac up in my tanks with 3mm as opposed to the ones with 6mm Link to comment Share on other sites More sharing options...
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