Re: PO4 "buffers"

[Thomas Barr <tcbiii at earthlink_net>]

> Could someone tell me if algae is the only reason
> phosphate buffers aren't recommended for planted
> tanks? 

No. Algae is often associated with PO4 but PO4 by itself doesn't "cause"
algae. It is a combination of things besides PO4 and sometimes can be traced
to a single issue(CO2, lack of NO3, PO4 even). Sometimes adding some to an
already preexisting problem will increase algal growth and removing it will
reduce algae growth, but will not get rid of it etc.
(Tossing a log on fire vs tossing a log on pile of wood not burning)

> It seems to be pretty canonized, but it's
> difficult to find definitive info in the archives or
> anywhere else. I'd really appreciate a reply, since
> I'm having buffering problems and trying to fix it
> before turning my tank into an acid bath!

It's not the PO4 that's the algae issue. It was thought to be at one point.

Buffering problems? Tell more here.

Folks confuse low pH with good CO2 levels but there's more to CO2 than
merely pH, KH is the other part and it takes both to determine a good CO2
level. Then they read aquatic plants prefer soft acid water.

Adding "buffers" that change pH will not solve low CO2 problems. Only adding
CO2 itself will change that. That is what the plants are after, not buffers.

Baking soda will raise your KH, alkalinity, and you use this measurement +
pH, not just pH alone, to find the CO2 level. 20-30ppm of CO2 is what you
want. Do not monkey with pH controlling buffers etc. Set your KH at 3
degrees (about 50ppm) and add enough CO2 to get a good range(about 6.4-6.6).

See the pH/KH/CO2 table at www.sfbaaps.com for different KH values to see
where your pH should be. Use only CO2 gas to change your pH. Not PO4
buffers/acid "buffers". Test your KH first then find the pH you need.

That might be more helpful and more relevant to your issue.
Regards, 
Tom Barr












   

> Erin