Lowering alkalinity of water?

[hattori]

The water in all of my tanks - fish, newts, and turtles - is high in alkaline, which means that I cannot lower the pH to the necessary level. Does anyone have any suggestions on how to lower it?

The water I use to begin with is just tap water, which is about a 6.4 on the pH scale. It's on the acidic side, not the alkalinc (not a word, I know) side.

Yet anytime I use it it instantly shoots up into the 7.8-8 area. Two of the tanks, newt and turtle, have repti-carpet for the bottom, a few large rocks, some aquatic plants, and 1 has a small terra cotta pot in it. The fish tank - 55 gallon - has gravel, tons of plants, and two small terra cotta pots. I've heard rumors that terra cotta pots could be doing that, but very few people have said that they've ever had that problem.

Any ideas?

 

[JWERNER]

So you have 3 tanks total and two have Terra cotta but all 3 still have high alkalinity?

Have you left the source water to sit for a few hours then tested it to see if it raises then?

I would say the repti carpet. I personally dont know if I could trust that for that long in a wet environment.

 

[Jennewt]

Right, try leaving some tap water out, maybe even bubble it with air, and then test the pH.

I wouldn't worry about a tank with a pH of 7.8-8.0. Some of mine are there too because of the tap water here. You are likely to do more harm than good if you try to change it.

 

[hattori]

Well, when it comes to the fish tank, I need a pH of exactly 7.0, so...

I'd say it's the repti-carpet but it's only in two of the tanks.

None of them have things similar to the other two...

I'll try letting it sit out.

 

[Chopper Greg]

Well, when it comes to the fish tank, I need a pH of exactly 7.0, so...

I'd say it's the repti-carpet but it's only in two of the tanks.

None of them have things similar to the other two...

I'll try letting it sit out.

As others have mentioned, leave the water out and/or bubble it for a while and then test the pH.

But your pH is not the only issue here - or I should say it is not the original problem but the result of a number of factors influencing your water chemistry.

If you can test for the hardness of the water ( both general and carbonate harness - aquarium pharmaceuticals make a dual GH & KH test kit, I'm sure other companies do to ), both before and after you let it set out, then it will give a better idea of the issues that you face with your water - I suspect that you may have some buffering issues, that will affect your ability to change the pH, on a long term basis - namely minerals in the water that are reacting with the CO2 in the air and those same minerals could cause your water to resist a change in pH.

Two more questions -

How long have your tanks been active and how are they decorated?

 

[hattori]

I let the water that I use - straight from the tap, 6.4 pH - sit for a few hours, and it has the same pH. I also tried letting a terra cotta pot sit in a few hours, and it's still the same.

The newt tank and the turtle tank are both divided into two sections via siliconed plexiglass. They're both about 80% water, 20% land. They both have the same kind of plastic plant in them, as well as a plastic dip bowl containing large rocks and live plants. The bottom substrate is just repti-fiber. A friend of mine who's owned fish and turtles for years uses it in his tanks and has never had any problems with it.

The turtle tank has a filter, and both have some large rocks. The newt tank has a fan over it, and the turtle tank has a UV light.

The fish tank is just gravel, live plants, two small terra cotta pots, a filter, a heater, a thermometer, and a hood with light.

They have NO consistent similarities.

 

[Jennewt]

I agree with Chopper. If you really have to get the pH to 7.0, it would help to know what the GH and KH of the source water are. If the water is hard, it's unlikely that you'll be able to reduce the pH without resorting to using RO or distilled water as your source water.

 

[JWERNER]

Guys, we know its a buffering problem. As he states in even the title he cant straighten out his alkalinity. KH is a obsolete term. Kits that measure KH are measuring alkalinity.

Also where the PH might be at a OK level alkalinity could also cause it to swing at times.


How about filter media? Do you use any that could be messing with the alkalinity like carbon? Do you keep up witch changing it if so?

This is a long shot, but what about your bucket or what ever you use for changes? Has anyone used it for something other than water changes?

 

[cfirment]

Another option for you to try would be to add a more acidic buffer. This can be done by simply adding a piece of bark, or peat to the tank. It can be a slow process depending on the chemistry of your water but is much more safe than using chemicals. You may however experience some water discoloration.

If you do decide to try this method, or any method, I would first test it far away from your tanks. Changing the pH of water, and keeping it there, is usually not easy.

 

[JWERNER]

Peat in a sack in a filter compartment might work.

It shouldnt get thrown off by the alkalinity since its a solid source.

But I know what its like when somethings wrong. Sometimes you are compelled to figure out what it is regardless.

 

[Jennewt]

Guys, we know its a buffering problem. As he states in even the title he cant straighten out his alkalinity.

I'm not taking the message title too literally because many people don't understand the difference between 'water with high alkalinity' and 'highly alkaline water'. Hattori seems to know the pH, but it would sure help to have a measurement of the actual alkalinity (hardness), both in the tanks and in the source water.

Do the tanks have a lot of healthy live plants? A heavy load of growing plants is another thing that can push the pH upward.

 

[hattori]

I use an Aqua Clear filter from Hagen in the big fish tank, a repto-min filter in the turtle tank, and no filter in the newt tank.

I'm going to go to the store today and get a test kit for checking the various levels of nitrates and such in my water.

I was actually going to try the driftwood trick - where you get driftwood and it miraculously transforms your pH - but my beach trip was canceled...I would get some from the store but it's like 5 bucks per twig here.

I'll get the kit and update...

(BTW - I'm female, just so you know. haha )

 

[Mac Myers]

I got a C in Chemistry... but what kind of rocks are they?

 

[hattori]

Just rocks from outside. I've used them in prior tanks with no pH problems before.

 

[Chopper Greg]

Guys, we know its a buffering problem. As he states in even the title he cant straighten out his alkalinity. KH is a obsolete term. Kits that measure KH are measuring alkalinity.

The kits that measure the KH is measuring the Carbonate (CO32-) and Bicarbonate (HCO3-) ions, and these can be affected even by the use of plants and even the type of plants, as they take up CO2 and release O2 during the day and take up O2 and release CO2 at night - this is why the pH in a pond can drop during the day when the sun is out but rise again at night. Deionized water is about the only way to effectively deal with this problem.

The kit's that measure the General Hardness, is measuring the minerals ( including alkaline minerals like calcium ) in an aquarium - without a major water change they can build up in the aquarium and increase the hardness - a prime source is the vitamin/mineral dusting powders, that feeder insects are covered with. This problem can be dealt with in the short term by doing some major water changes and in the long term by being careful about the minerals that are being put in the tank, and increasing the water changes.

I'm being very hesitant to mention it, but a few people resort to adding sulfur that binds with the minerals and makes them more soluble to make their transport out of the tank easier with water changes, but, it's not for those that don't have access to test kits or will test the water fairly frequently, because it can cause a major pH swing in a short amount of time.


Hattori -

Minerals can come from a number of sources - including the dusting powder that covers your feeder insects and the terra cotta pots, but in the case of the terra cotta post, it will take days ( even weeks ) to slowly leach out...without knowing the type of gravel you could be adding minerals that are pushing the pH up.

Without knowing the specific reason for the rise in pH you have no way of knowing what the best course of action is, that is why you really do want to test both the general hardness and the carbonate hardness.