pH problem

[modernhamlet]

I'm having a hard time keeping the pH of my 29g tank steady. It continues to drop down to 6.0 (the lowest on my pH scale), forcing me to do water changes far more often than the parameters suggest would be necessary.

ammonia/nitrite = 0
nitrate = 5-20ppm, usually fairly steady in the 10ppm range
pH (tapwater)= 7.0 -7.2

The tank is well planted and nitrates rise very slowly, if at all.

General Hardness has always been around 7-8 dH, but I don't have a Carbonate Hardness test kit. The one time I had the LFS test it, kH was only around 2-3 dH. I assume this lack of alkalinity is a major part of the problem. For awhile, the pH only drifted from 6.8 to 6.5 between weekly waterchanges. Now it's hard to keep it above 6.5 without 2 or 3 water changes in quick succession.

So my question is, how do I maintain a more stable pH without endangering the fish? I don't mind 6.5, or even 6.3, but when the readings drop off the scale and leave me blind, I get worried.

Thanks in advance...

 

[gixer]

its your kh mate.....talk tomorrow,,,its 2.30 am and its too intense talking about water chemistry now


later

 

[tstenback]

Modernhamlet in the past i have successfully used crushed coral in the filter to raise PH. It takes a bit of experimentation to get the right amount but knowing you are as cautious as i am you will add a small amount at a time. Seemed to create a very stable environment with low maintenance. I will try to find the article i used when investigating this myself and will repost if i find it. HTH

 

[G_Sharky]

Hey modernhamlet if you want your ph to be stable then i suggest using aged tap water( meaning keep water in a container with an airpump or something to agitate it). I keep a 20 gallon garbage bin as a storage for water and my ph and kh, gh never change a beat or went unstable....Just my 2 Cents....

 

[rollntider]

water PH will drop if you have low akalinity, bump your alkalinity up and it will remain stable i promise. When i cleaned swimming pools we didnt add or lower PH we kept them at 80 to120 ppm (not sure what that is on the KH scale) I used to add some baking soda each water change, but now i have found these fizz tablets from junglke that maintain ph, and it works. I just add a tablet after my 4th water change and my ph stays constant. (stablized chlorine has a low ph where as non stablized is a high PH. Pool "shock" or granular is usually not stablized is more concentrated but doesnt last long. Chlorine tablet are stabilized with an acid and thus stays in the water longer. Also the shock breaks the ammonia away from the chlorine, thus eliminating the chlorimine and making the chlorine more potent) Ok I could go on about chlorine, and that was some useless info, but may be of some help, in other words adjust your alkalinity and the PH will remain stable.

Sharky different water systems deal with water differently. our water system will drop the ph over days because the chlorine they use is a high ph chlorine and as it disipates the ph drops, the alkalinity is very low. So your water in your area may be very alkaline so hence the reason it is stable. Here our water isnt very high in alkalinty and the ph flucuates.

 

[tstenback]

Here's the article Water Chemistry HTH

 

[modernhamlet]

Thanks for the advice everyone!

Looks like I should invest in a kH testing kit. If I'm going to keep the tank stable, I have to know what the parameters are.

My major concern is that just about anything I add to increase the kH is going to increase pH as well. Messing with water chemistry is a scary proposition. I'll just take it very slow until some sort of balance is reached.

 

[gixer]

i suspect you have a very low kh reading. (you need that test) adding shells or crushed coral will deffinatly raise your kh and will slightly raise your ph but i'm not talking loads of the stuff. this will stabalise it and at the moment the way you ph is fluctuating is much more dangerous to your fish than raising your ph a little.

the lower your kh. the more unstable you ph will be. ph crashes can be fatal to a lot of fish. raising you ph by about .4 certainly will not,

but deffinatly get a reading for your kh before you do anything else

HTH

 

[modernhamlet]

Ok, I'm now in possession of 1 kH test kit and a small chunk of holey rock. I'll see what the readings for pH and kH are tonight and then decide whether to add the rock to the tank.

 

[gixer]

be interested to see what your kh is....post the results

 

[modernhamlet]

I just tested. It's a dropper test, so the first drop of the test solution should change the color to blue, then, you count drops 'til the color turns yellow.

It turned yellow on the first drop. My kH is <1 dkH.

Well... I guess that explains my problem!

I put the small piece of holey rock (a little less than fist sized) in the tank right away. I hope it helps.

I'd still like to keep the water fairly soft, just a little more stable. What's a good point to keep it? I was thinking around 3 dkH.

 

[gixer]

at least 3.... under 3 is pretty unstable...aim for about 4 i would say..

 

[Bol]

3-6 degrees is often cited as a target for "good" KH.

By the way, if the rock isn't doing it for you, you can also use this, easily and safely:

1 teaspoon of baking soda will raise the KH of 50L (~13 US gallons) by 4 degrees.

And, as a side note, KH doesn't have anything to do with "hard" or "soft" water -- that's GH. You can pump up the KH as high as you like, and the "hardness" of the water won't change.