Where is the buffer?

[thacarter546]

Ive been messing with my set-up again. I have tested my water before, but I dont test very frequently. I bought a peacock at petco that didnt make it. MY LFS is crap!!!! 'theytake care of the marine aquatics but the Fresh water is all dead or dying. Anyway this dude didnt make it. Took a water sample in my PH is 6.4!!!

I have hard water with a high ph from the tap, I cant figure out where my buffer is. I did add 20 lbs of laterite and a 12lb stone covered with java moss. I figure it may be the stone, but its been in another aquarium, (not one of mine) for a year or so. Ive added 4 terra cotta pots, 5 new species of plants and a Yeast CO2 set-up. Thats all I can think of.

Also, I bought a brand new API master test kit to double check their results. Tap water comes out at ph 8.8 tank water stays at 6.4.

Nitrates were kinda high, but it was right before my weekly water change. No nitrites, a touch of ammonia 0.25ppm (Tank has been up and running for several years) Kinda wondering if I need to cram some more bio media in. So far its got 40 rena stars, 2 litre biomax, 2 litres denitrate, and 2 biowheels

 

[duanes]

Just because you have a high pH, doesn't mean your water has buffering capacity. Alkalinity is the measure of buffering capacity, a high alkalinity means your water can buffer the acids produced by fish waste, plant and other metabolites. If your water doesn't buffer on its own, a substrate of crushed coral, or fluidized bed reactor of aragonite can help.
A slow drip of baking soda also buffers.
But if the bioload is too high for your amount of water changes, the above won't help.
I doubt the stone could reduce buffering unless it is made of acidic rock.
You do not say your fish load or size tank, it may overwhelm the waters capacity to buffer if you do few water changes. Sounds like you need more frequent ones.

 

[frickr]

let some tap water sit out overnight after dechlorinating it, and read the ph in the morning. sometimes water coming out of the tap will be higher in ph due to the dissolved gasses. also adding co2 will lower the ph if the concentration is high enough. i would think you would need a pressurized system to be able to produce enough gas to lower the ph that dramatically though.