Re: PO4 "buffers"

[Thomas Barr <tcbiii at earthlink_net>]

> Thomas Barr wrote:
>> Buffering problems? Tell more here.
> 
> The problem to which I was referring is this: I've
> been using a phosphate buffer because my tap's 8.0, KH
> 4. I've been using it the last couple of months and
> everything's been okay, not even a problematic algae
> outbreak. But the other day I noticed my fish acting
> stressed and the pH was below 6.5 (Tetra test-- not
> exactly the 6.5 color but not the 6.0!). And my
> usually stable 4 KH was 2.5. I don't inject CO2-- I
> use Flourish Excel for a carbon source (because of
> space, time, money, lack of knowhow).

There is the issue.
If you don't mess with CO2, don't worry about the pH. It's going to move
around especially during the middle late parts of the day(it'll get higher)
and at night it will drop again.
This is natural/normal if you don't use CO2. Using excel may prevent as much
of this effect but depending on light, perhaps nutrient status, it will
still vary. 

But if you want to supply Carbon to your plants, the Excel is not cutting it
here. You need to use gas if the pH rises since the plants are removing both
the excel and the CO2 from the water.
Perhaps the CO2 is removed first, then the plants take in the next best
thing, the Excel. Not sure about how that works.

Perhaps others using it will comment that have measured the pH vs using it
vs not using it.

You could try it, space, time and money should not be an issue for not using
CO2 gas. DIY CO2 is cheaper, saves much more time and $. Excel works well
for folks that need to do the daily thing and for smaller tanks with less
light but it's extremely difficult to argue against DIY on cost, space, time
issues vs Excel.  

> The Flourish
> wouldn't lower PH, would it?

Not directly. Maybe by increasing plant uptake if traces are limiting which
will create more CO2 demand. But this is unlikely.

> So are the plants
> utilizing the carbon to the point that it's lowering
> KH (I've read some can do this)?

Yes. The KH tends not to move much if the plants have enough CO2. By not
using CO2 they will go after the KH(HCO3). Don't approach this non CO2 tank
with CO2 enriched ideas.

>Thanks for your time
> and info-- I'll try the baking soda thing to get it up
> a little more. But excepting CO2, what's the "best"
> way to get my tap back down to a livable pH?

Livable? What do think happens in nature? pH swings in shallow lakes/ponds
filled with vegetation ph swings are simply part of the cycle.
Don't do anything. Leave it alone.

All I do for a non CO2 plant tank is top off water for evaporation. I don't
fret over pH etc, I clean and prune every so often, but that's not much. I
add some plants that use HCO3 like Egeria etc, the tank is also well packed
with plants, has a deep substrate(I use flourite + some peat, mulm etc)
algae eaters, 2 watts a gallon of reg FL lights.

The idea behind a non CO2 tank is less maintenance and less growth to deal
with, few water changes(the time issue use mentioned and cost issue). It
takes more playing as far as what plant will or will not make it, but you
still get a large number of plant choices.

I don't add anything to the tank except a good fish feeding once a day. Top
off once a week. Adding some traces every so often likely won't hurt much
but I've not needed too unless I added CO2.
You can add CO2 for awhile to get the tank grown in well then remove it
also.

Regards, 
Tom Barr 

> Erin Poythress