phosphate control

[M Woodhill]

the phosphate level of my tank always fluctuates

from 0.07 down to 0.00

wasup?

i'm runnin a BRS GFO and Carbon reactor and put Seachem Phosguard in the sock

[Allmost]

po4 is 0.07
you put in GFO
it reduces it to 0.00
then GFO takes up all the po4 it can and gets shut
so your po4 raises, till you replce the GFO again.


try replacing GFO when you notice po4 raising.

[disc1]

You may be seeing a small fluctuation or you may be seeing testing noise.

How are you measuring phosphate?

Let's take for example the Hanna checker that everyone loves. Now let's add the error numbers to the results.

So you got:

0.00 (+- 0.04)

and

0.07 (+- 0.04)


With the numbers written that way does it make more sense what's going on?

[Randy Holmes-Farley]

As folks mention, I think we'd need to know more to answer your question well.

[M Woodhill]

well, what i use is Hanna

When i notice there's an increase, i always change the GFO

but sometimes things go weird, cuz GFO seemingly worked only within few days

isn't it too fast or probably its just testin noise?

the actually level is around 0.03 as described above?

so how could i reduce the phos level stably to 0.00?

[Randy Holmes-Farley]

Is this the Hanna 713? If so, you cannot necessarily distinguish 0.00 from 0.08 ppm. If the actual value is 0.04 ppm, and with the claimed uncertainty of 0.04 ppm, then the measured values could range from 0.00 to 0.08 ppm.

GFO can be depleted in a few days, or it may last longer depending on the flow through it and the amount of phosphate present in the water.

I'm not sure 0.00 ppm phosphate should be the goal, but if it is, more GFO replaced more frequently will attain that in most any tank. The concern might be overdoing it and driving phosphate too low.

[M Woodhill]

Is this the Hanna 713? If so, you cannot necessarily distinguish 0.00 from 0.08 ppm. If the actual value is 0.04 ppm, and with the claimed uncertainty of 0.04 ppm, then the measured values could range from 0.00 to 0.08 ppm.

GFO can be depleted in a few days, or it may last longer depending on the flow through it and the amount of phosphate present in the water.

I'm not sure 0.00 ppm phosphate should be the goal, but if it is, more GFO replaced more frequently will attain that in most any tank. The concern might be overdoing it and driving phosphate too low.

i don't know the series number of the hanna checker

but it's not the old and big style but the latest green pocket-size and less expensive one

i have some algae problem and they say undetectable level of phosphate will be eliminatin algae in a tank

so i'm tryin to make phos level 0.00

[bertoni]

The accuracy of the unit is +/- 0.04 ppm, so the tank might be running around 0.03 ppm steadily, for example. The level might be fluctuating, though, as well. I'd probably start changing the GFO on a regular basis, and see how the measurements respond. How big is the tank, and how much of the PhosGuard is in the sock?