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View Full Version : Low PH, high alkalinity.



domjd05
10-10-2008, 05:17 PM
There is one basic concept about PH and alkalinity I do not understand. When you lower your PH, it makes the water more acidic.. when you raise it, you make it more alkaline... Alkalinity is also your tanks ability to buffer ph.. correct? So how can you lower your ph, while still maintaining a good level of alkalinity to buffer your ph?

Northernguy
10-10-2008, 06:10 PM
Driftwood helps to buffer your ph a little bit!

Why do you want to mess with your ph.If you have fish in your tank you could kill them if you alter too much too fast.
There is a thread on baking soda used to raise it somewhere.
Most fish will adjust to whatever your tank ph is, as long as its not too low.

domjd05
10-10-2008, 06:41 PM
you think a group of discus can adapt to 7.4 PH? This is what I get out of my tap... someone let me know if its a good idea because I'd have no problem with that.

Northernguy
10-10-2008, 07:43 PM
I am not an expert but I am sure someone will drop by let you know!

I think that your discus will adapt to that.
Are they in the tank now?

domjd05
10-10-2008, 07:49 PM
They are in the tank now... the now is 6.6 I have been using ph down in my water changes to keep the ph the same.. its hard.

driftwood will help the alkalinity.. good. But will it raise the ph? is it even possible obtain a high level of alkalinity while maintaining an acidic ph? (6.6) ugh

Alfcea
10-10-2008, 07:55 PM
There is one basic concept about PH and alkalinity I do not understand. When you lower your PH, it makes the water more acidic.. when you raise it, you make it more alkaline... Alkalinity is also your tanks ability to buffer ph.. correct? So how can you lower your ph, while still maintaining a good level of alkalinity to buffer your ph?

Hello domjd05,

Thanks for asking this question. You are totally right. Alkalinity is a measure of the buffering capacity of the water but only at higher pH's. It is one basic concept of chemistry that has to do with the ability of an acid or a base to react with other acids or bases -a property known as acidity constant, or pKa-. Carbonate and bicarbonate ions (CO32- and HCO3-) are great buffering agents but only at the higher end of the biologically useful spectrum. Carbonic acid, which can be formed from either carbonate ions or bare CO2 gas will "buffer" the pH at very low values (about 3 or 4) and therefore, it is useless for this purpose. In fact, that is why aquarium keepers who fertilize with CO2 have to keep a close eye on the pH...

To buffer your pH at the lower end of the biologically useful spectrum (say 5.5 to 6.5), substances other than carbonates should be used. Amongst the most useful and least dangerous are derivatives of "tannic acids", or tannins from driftwood. They will buffer (stabilize) your water at a "nice" pH for fish coming from the Amazon basin, for example, or the discus you wish to keep.

I hope this info is useful for you...

domjd05
10-10-2008, 08:10 PM
Thank you for the brilliant response. Tannins will stain the water somewhat won't they? If I let the driftwood sit in another tank for awhile to let the tannins they stain out, will it still be effective in my discus tank?

Alfcea
10-10-2008, 08:17 PM
Yes, they will stain the water. If you boil the driftwood or just let it sit in water for a while, they will leach away, for the most part. You don't need a lot of tannins to buffer your pH at the target value, so a light yellow tinge in your tank would be more than enough... I actually enjoy the colour of tea in my tanks very much... but hey!, that's just me...

domjd05
10-10-2008, 08:19 PM
I will try this, thanks.

domjd05
10-10-2008, 08:55 PM
So I just set my tank at 6.6, put in the driftwood, and wait for the buffers to build up? Will it alter my PH? (granted I know this won't all happen in 5 minutes...)

smaug
10-10-2008, 10:08 PM
Thats the trick isn't it?Through the use of a quality non phosphate based product such as seachem acid buffer is how I do it.Most will tell you to not mess with your ph.I say this is a hobby and adjusting your ph to the ideal range for your selected biotope is just another level to the hobby.Go for it if you want that xtra level,leave it alone if your happy where you are.
btw,driftwood will do only a very little to adjust ph or buffer for that matter.The biggest change in ph I have ever had due to wood was .2.

Alfcea
10-10-2008, 11:33 PM
...The biggest change in ph I have ever had due to wood was .2.

What was your initial pH? If it was already low enough (say 6.5-ish), the driftwood would not bring it much lower because the pH would already be at the "buffering" pH of it... The other possibility would be that the concentration of carbonates was too high, and in that case, they were the ones buffering your tank and the tannins would be all neutralized before allowing them to bring the pH lower...

smaug
10-11-2008, 02:03 AM
Ive had wood in waters with a ph from 7.5-6.8 with no bigger change then .2.
even my wifes 3 gal nano has a piece of wood in it and it takes up a full 20% of the water space even that isnt doing much to the ph.