Low Ph

L

lauren

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How does one correct a tank where the pH is constantly low? I have a cycled 20 gallon tank and I do 30% water changes once a week with a siphon. My tap water is around pH 8. Ammonia, nitrates, and nitrites are always zero. Yet when I test the water even 2 days after a change (with no food being deposited on the substrate), the pH is as low as 4!

The Ph of my small non-filtered tank in the same room is 7.5. The pH of my 10 gallon fish-tank is 7.0, but it also had low pH before I added a heater. Could there be some kind of cold water-loving bacteria or algae that is producing acid?
 
The pH of any healthy tank with soft water will naturally drop over time. Normal metabolic processes (like the decay that occurs in filters) produces acid.

There are several things you can add safely to maintain the pH: limestone rock, crushed shell (like they sell for saltwater tanks), or Calci-Sand (like they sell for reptiles). These can be put directly in the tank, or the latter ones can be put in a bag in the filter.
 
Jennifer -

Can I use calcisand as a substrate? Or will it dissolve in the water?

I was thinking about to switching to sand to cut down on the bacteria - it's visible on the plastic plants.
 
You could probably use Calcisand as sand in the tank, although I've never actually done so. It does dissolve a tiny bit over time, but hardly enough to notice.

I'm not sure what you mean about sand cutting down on the bacteria. One of the virtues of sand is that it provides more surface area for the growth of beneficial bacteria. Bacteria in a tank are a GOOD thing in most cases. What exactly do you see on the plants?
 
Here are pictures I took of the plants a few minutes ago. My axolotl has been out of that tank since Thursday morning, and this is actually increased growth since then!

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The other plants have smaller leaves, and so have smaller amounts of growth. The water temp is 65 degrees and the pH is still around 4.
 
WHOA! A pH of 4 is not safe at all! Are you sure it's actually 4? I'd purchase a high quality test kit (or take it to the pet shop) and test it.

As for the gunk on the plants, looks vaguely fungus-y or like algae, not bacterial. Take 'em out and scrub 'em.
 
The pH of 4 is a reading from an electronic pH meter, the test strip and chemical test kits I bought dont go below 6, so they are saying 6. Luckily I got my axolotl out when it first crashed, so he's fine now in a non-filtered container.

Is there any way to get rid of such fungus or algae on a permanent basis besides just scrubbing? If that is what this is, I had the same thing in my fish tank before I got a heater (which apparently killed it). Whatever it is must be floating around in my house!
 
You'd be surprised what's floating around your house. If you ever get a chance to culture some dust, it's GROSS!

As for the pH, harder water's usually more alkaline, so I suggest probably a huge water change (if not complete dismantling and rebuilding) and add some calcium carbonate (in the form of crushed sea shells, calci-sand, etc).

Good luck.
 
If the pH changes so much so soon after a water change, and your other tanks are fine, then it seems there is something in the tank that's changing the pH. Do you have a light for the axie tank with the plants? Maybe the plants are dying because they don't get enough light? That's what happened to some of my plants.

There's always chemicals you can add (like pH UP and ph DOWN) that will raise and lower your pH.
 
Halszka, The plants in there are plastic, and lights tend to heat the water, so I don't use one for my axie tank.

Joan - I already figured I would have to dismantle. I'm going to try and use calci-sand as a substrate (I have some on hand for my gecko and see if that works.) Do you think filtering the water might be softening it? Would it be better to use tap water with conditioners instead?
 
I think it's the water filter that is softening it. Most tap water is hard water unless it comes from a well. Back in my home town, we had soft water. It was terrible! Here in The City several states away our water is just right as far as PH goes. I would stop using the filer and test out the water PH with out it.
 
Lauren, what kind of filter were you using? That fuzz on the plants isn't identifiable to me, but I would bet that the low pH has something to do with it.

Regarding those pH UP and DOWN solutions that you get with test kits... I would never ever recommend using them. They will certainly get the pH to where you want it, but it will just go back again within a few days. Rapid pH swings like that are baaaad news for animals. If you really need to adjust the pH artificially, you need to use a buffer solution, which is a product that they do sell for aquariums. It's rare that one has to resort to that for caudates though.
 
Jennifer - It's a Brita canister filter attached right to my faucet. I was using it because other-wise the water is a discolored greenish. But I would gladly trade low pH for that!

I learned today that too much CO2 in the water can also lower pH, so when I rebuild this set-up tomorrow I'm probably going to buy some real plants.
 
The Brita filter will not make the water any softer. Brita-filtered water should be excellent water to use for aquariums. Let us know how it goes with the calci-sand in the tank.
 
Ok, i have had the same problem for months. I added coral to my corner filters, which seems to have helped a little, but still regular water changes and the ocassional bit of carbonate hardness generator are needed.
After months of trying to figure it out, I can only deduce that the drop in ph is due to the co2 (cause im one of those dreadful smokers) in the air, being pumed through my tanks air lines.
Since i started smoking in another room, the tanks are a bit more stable. Dont know if this helps you. Its been driving me nuts for months, hope you have better luck.

Oh and the white fuzz, i suspect its axie skin. When the ph drops below 6, the water becomes acidic. This in turn makes the axies "peel" and their skin brushes off on plants.

(Message edited by lisapie on August 31, 2005)
 
Lisa, I'm thinking it is the CO2 also, which is why I am going to buy live plants tomorrow. It definitely not axie skin, since he hasn't been in there for nearly a week, and since the plastic plants were removed it began growing on the gravel. I think that it is the source of the CO2. But tomorrow it will go down the drain!
 
Lauren- this sounds like a condition that can usually be seen in a tank that is either overfed or one in which uneaten particles are not removed.

The white growths are likely to be molds which can grow on any uneaten particle of food and spread. It could also be a fungus. Examination under a microscope at your local highschool, college biology dept would tell.

Either way, many of the processes that "feed" on uneaten particles are aerobic. Using oxygen and generating CO2. CO2 dissolved in water is Carbonic Acid. Carbonic acid is always in equilibrium with CO2 in water which means it is limited by how much CO2 is present. It can reach a PH of 5.6 when in equilibrium with atmospheric CO2 so the increase in the water by decay processes could push it lower.

Basically, remove and clean the plants. Wash the gravel gently or siphon well to remove any mulm. Do this carefully if the tank was cycled as you don't want to kill the good bacteria.

If you don't have an under gravel filter under your gravel then you should churn it a bit from time to time to make sure no aerobic pockets build up. The same goes for a sand bed if you don't have live plants and or sand sifters to stir it up for you.

Kevin
 
That white stuff looks similar to a fungus I once had in my sub-tropical fishtank. It killed all my fish - twice!!!
The fungus I had was caused by my sister over-feeding the fish while I was away.
The only way I could get rid of it, so as to be able to use the tank again, was to sterilise everything that went into it(including the gravel and the tank itself), and start all over again.
I'm hoping that you don't have to resort to these measures though. So defiantely scrub the plants, and change the substrate that you're using.
Hope this helps.
 
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