Aquarium Forum

  · Tropical Fish Home
· Fish News
· Aquarium Forum
· Buy & Sell
· Calculators
· Equipment reviews
· Free Aquarium Ebook
· Feedback
· Link to us
· Photo gallery
· Plant species
· Tropica Plant DB
Tropical fish species
· By Common name
· By Scientific name
Tropical Marine fish
· By Common name
· By Scientific name

        Via paypal

  · African Cichlids
· Algae Control
· Aquarium Decoration
· Aquarium Resources
· Aquatic Plants
· Barb Fish
· Betta Fish
· Breeding Fish
· Catfish
· Central American Cichlids
· Cichlids
· Clownfish
· Corals
· Corydoras Catfish
· Discus Fish
· Dwarf Cichlids
· Fish Diseases
· Frogs and Turtles
· Goby Fish
· Goldfish
· Gourami
· Invertebrates
· Jellyfish
· Killiefish
· Lake Victoria Cichlids
· Livebearers
· Malawi Cichlids
· Marine Aquariums
· Marine Aquarium Fish
· Other Fish
· Pleco
· Predatory Fish
· Photography
· Pond Fish
· Responsible Fish Keeping
· Rainbow Fish
· Shark Fish
· South American Cichlids
· Tanganyika Cichlids
· Tetra Fish
· Tropical Fish Food
Results 1 to 9 of 9
  1. Default pH and acquarium gravel

    0 Not allowed!
    I've got a question about pH. I set up a new tank, and the pH went from ~7.4 to ~8.5 in a week, and I'm trying to figure out why. Here's what happened:

    I'm brand-new to the hobby... used to help my parents keep fish when I was a kid, and am now getting back into it 25 years later. I'm starting up my first tank, a 29 gallon. I've been researching a LOT, and am getting ready to do a fishless cycle.

    I started last week, just getting everything into the tank and filling it with water, making sure the filters and heaters worked, and so forth. I figured I'd get a head start on cycling and put in some pure household ammonia (Ammonium Hydroxide), but I only got it to 1-2ppm (I now realize that wasn't enough)- my point is that I didn't add much ammonia (which I understand can raise pH). I've pretty much left the tank alone since, figuring I'd mess with it again this weekend.

    I retested it and the pH was up to 8.5. The only thing I have in the tank is gravel and some rocks I bought from an LFS. I've read about the wrong kind of rock raising the pH, and on a whim added some of the gravel to a bowl with some vinegar in it. Several of the pebbles (it was a mix of white / brown / black) were shortly covered with bubbles (the black ones).

    This was gravel sold specifically for aquarium use, and allegedly had some sort of coating. I'm pretty sure it does, because after leaving the gravel in the vinegar a few hours there was something flaking off the black pebbles.

    So, some online resources suggest that rocks which bubble in vinegar should be avoided. But there are plenty of other places where people talk about adding certain kinds of rock specifically to increase alkalinity and improve buffering. And others that suggests it's unlikely to get the pH that high just from adding rock.

    Other random facts which may or may not be relevant: I don't have a kh test kit. Our local water supply uses chloramine, and I treated it with Prime.

    So... is this something I need to be concerned about? My main concern is whether I should dump the gravel and try something else before I invest time in cycling the tank.

  2. #2


    1 Not allowed!
    What exact type of substrate did you use ? Some substrates that are meant for marine aquariums can raise pH when used in a freshwater aquariums.

    Also, with high amounts of ammonia in your water, your pH will also be somewhat unstable.

    You might want to test your tap water followed by testing the same sample of water after it has been sitting for 24 hours to see if the pH of your water supply is stable.
    If you take your time to do the research FIRST, you can successfully set-up and keep ANY type of aquarium with ease.
    "Not using a quarantine tank is like playing Russian roulette. Nobody wins the game, some people just get to play longer than others." - Anthony Calfo
    Fishless Cycle Cycling with Fish Marine Aquarium Info [URL=""]

  3. #3


    1 Not allowed!
    Anything that responds to vinegar (well done finding that!) will leak minerals and will increase PH and hardness. Which is why you also should test the rocks. It really is that simple. I've lost almost an entire tank once due to aquarium gravel that was relabled repto stuff.

    Now increasing hardness isn't a problem if you keep hardwater species or marine but it is a problem if you want to keep something softwater

  4. Default

    0 Not allowed!
    OK! Unfortunately I threw away the packaging so I will have to go back to the LFS to see what gravel I actually bought. It wasn't prominently marked "marine", but it's possible I missed that.

    I've got some tap water sitting out that I'll test for pH later. I'll report back!

  5. #5


    2 Not allowed!
    Final word, Ph is nice and you want it at stable as possible, but GH is at least as important and possibly more. Try to match this to what you keep.

  6. #6

    Join Date
    Nov 2008
    Vancouver, BC, Canada

    Awards Showcase

    【ツ】 - korith So glad someone else takes KH seriously! - talldutchie most promising newbie award! - talldutchie Good advice. Stick around! - ~firefly~ A gift for your knowledge of Tetras. - steeler1 
    For your continuing wise words - ~firefly~ Thanks for your detailed and informative post. It is a pleasure having you here. - William A second gift.  Since I saw you just recieved another Sea Horse ;-) - William thanks for helping me with your informative posts - vafa Grats on MOTM to the Tetra King. - Spardas 


    0 Not allowed!
    aGREE WITH WHAT HAS BEEN POSTED. As well as marine substrates, there are cases in freshwater when you might want such a substrate that increases GH and pH, such as for livebearers and rift lake cichlids. But as someone said, for soft water fish this is not advisable. So it depends upon what fish you intend keeping, whether this gravel may or may not be suitable.

    The rocks might also be calcareous, try the vinegar test on one of them too.

    Once we know the pH of the tap water to compare it, plus the GH, and what fish are intended, we can wrap all this together.

    Byron Hosking, BMus, MA
    Vancouver, BC, Canada

    Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

  7. Default

    0 Not allowed!
    Following up: I went back to the LFS, and verified that the rock I'd bought was actually intended for freshwater aquariums, but they agreed that it should not bubble in vinegar. I got to chatting with another customer / hobbits who extolled the virtues of sand, and after reading up further on it, decided to dump the defective gravel. I now have a nice sand substrate (*thoroughly* washed play sand, all the really fine stuff eliminated), and my pH has been staying put. Thanks everyone!

  8. #8


    0 Not allowed!
    Did you even test the pH in your tap water after letting it sit for about 24 hours ?

    That information can be helpful when you are planning your stocking for the tank
    If you take your time to do the research FIRST, you can successfully set-up and keep ANY type of aquarium with ease.
    "Not using a quarantine tank is like playing Russian roulette. Nobody wins the game, some people just get to play longer than others." - Anthony Calfo
    Fishless Cycle Cycling with Fish Marine Aquarium Info [URL=""]

  9. Default

    0 Not allowed!
    Yes. It did go up to about 8.2, and I'll be keeping that in mind when I stock.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts