[Rain_frog]

Well, I have a "low tech" planted tank. So far, my onion plant, aponogeton sp., and tiger lotus are doing well. I do not know the original pH value, but today I tested the water. I recently added some anacharis and hornwort last week and it is growing rampantly under a 96 watt quad (for a 29 gallon).

And, woah! the pH read 8.2 My kH is 5 or so.

This is too high for my tastes. I am aware of biogenic decalcification...but I'm very surprised the plants would jack it up that high. Do I necessarily need to add CO2 to my tank to lower the pH?

The water lily is planted in coco peat and there is wood which I would think would lower it.

 

[Chrona]

Well, I have a "low tech" planted tank. So far, my onion plant, aponogeton sp., and tiger lotus are doing well. I do not know the original pH value, but today I tested the water. I recently added some anacharis and hornwort last week and it is growing rampantly under a 96 watt quad (for a 29 gallon).

And, woah! the pH read 8.2 My kH is 5 or so.

This is too high for my tastes. I am aware of biogenic decalcification...but I'm very surprised the plants would jack it up that high. Do I necessarily need to add CO2 to my tank to lower the pH?

The water lily is planted in coco peat and there is wood which I would think would lower it.

Biogenic decalcification involves plants eating up carbonates, which should cause your pH to drop, and not rise to 8.2 no?

 

[Rain_frog]

that's not what I read. I've read that during this process, elodea and hornwort release hydroxide ion (OH-) which can soften the water, but also raise the pH.

http://www.aquabotanic.com/glossary.htm

 

[Chrona]

that's not what I read. I've read that during this process, elodea and hornwort release hydroxide ion (OH-) which can soften the water, but also raise the pH.

http://www.aquabotanic.com/glossary.htm

Ah, my mistake. At least I was half right though :hihi: