alkanitity

[alan j t]

hi all
my kh drops alot in my tank as well as the ph
if i dont change the water often
the kh is 120 and ph is 7.8 out of tap
i use proper ph 7in my barrel to pump to the tank
the tank is planted with flourite
in two days the kh is nill and ph is 6 or under
so now im changing water everyday

any one here has high kh then drops like flys

[fishgeek]

kh should be a reading of buffers in the water
do you add anything that could be binding to them, acid ? and using them up?

alternatively your kit is misreading , run the water into a bucket and leave standing or aerating for a day then remeasure, dissolved gases shouldnt affect the alkalinity

i've not seen your situation before

[alan j t]

i use a product called proper ph
i guess its a acid im not sure
i'll try aging the water and get back to you

[fishgeek]

most pH buffers contain both an acid and a buffer to try and achieve a set level of pH that should be stable

i dont know the product you use though reading on it may lead to an answer

[alan j t]

all it says is that its a phosphate buffer

[alan j t]

i brought the water to the lfs they tested the water with the strips as well
same sh*t
i bought the another test with test tubes and drops and color codes
everythings seems fine
i guess the water conditioner is giving me and the lfs false readings
ph says 6 on the strips and the drop test says its 7
the conditioner is made by aquarium pharmaceuticals inc
the strips dont expire til the end of this year 2008/12

[fishgeek]

a phosphate buffer is phosphoric acid and a phosphate salt, sodium-phosphate in mono,di or i think even tri forms

Kh is by definition is the carbonates , so i assume you have few carbonates in your water, and that your buffer is phosphates and no longer carbonates

I dont think any of the test kits around are actually specific enough to know this, most test alkalinity(ie any molecule that resists acid change in solution not solely carbonates)

Even if you start with carbonates (which you measure at 120 ?units?) and then find there are none, i think the phosphoric acid (in your buffer powder) that you are adding is binding to those carbonate molecules and leaving you with now a phophate based buffer system

if this is correct you still have a stable pH ... you could test that by just purchasing some hydrochloric acid(being australian you have a pool?) and dropping that slowly into a plastic bucket of your altered tank water and seeing if 24 hrs after doing so your pH can resist the acid change that should occur


alternatively i'm speaking crap,
did you test the water befre it goes into the tank and after it has been treated with the buffer?
if the kH has gone then my above ramble may be relevant


andrew