lowering po4 levels

john b.

Junior Poster
May 21, 2005
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I want to lower my po4 dosage in my 55 gal./high light tank. I am currently dosing 2 ppm. every other day.I want to know if I add 1 ppm instead of 2 ppm, will this be enough to be sure the po4 will not bottom out before adding more? How much on average does po4 get used up provided nothing else is in limmited quantities? Thanks for the help,
John
 

Spar

Guru Class Expert
Jun 5, 2005
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Dallas, TX
Re: lowering po4 levels

I have 5.2wpg on my 50-55g tank and dose up to 2.0ppm as well.

I have noticed that it diminishes by .15ppm per day. So, I add .3ppm every other day.

So, unless you can be 100% sure you always add po4 back at least 2x per week, lowering it to 1ppm is kind of risky. Maybe 1.5ppm instead? gives you over a week of "forgetting-period".
 

Tom Barr

Founder
Staff member
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Jan 23, 2005
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Re: lowering po4 levels

1 to 1.4 ppm a week is enough PO4.
But we tend to add more.

Doesn't hurt either way.
Green spot appears more as the PO4 is lowered.

Regards,
Tom Barr
 

john b.

Junior Poster
May 21, 2005
22
0
1
Re: lowering po4 levels

Tom Barr said:
1 to 1.4 ppm a week is enough PO4.
But we tend to add more.

Doesn't hurt either way.
Green spot appears more as the PO4 is lowered.

Regards,
Tom Barr
Two weeks ago I tested my po4 at weeks end, with a calibrated kit, and the level was 5 ppm. Last week I kept the po4 level at 2 ppm consistently and I noticed a dramatic decrease in green spot algae. It was not completely gone, but was alot less at the end of the week. Now I know one week is not enough time to draw any real conclusion, but there was still a noticeable change in the gs growth. I should also add that in this same week, I switched from csm+b to flourish and started adding 2 mls. of flourish iron every other day. Could these other changes account for the gs lessening?
This week I am goig to keep po4 levels at 2ppm again and see the results.If I get the same results, I will change back to my old po4 dosing routine(2 ppm every other day) with the addition of the flourish and iron to see if that makes any difference.Any comments on this idea? Thanks,
John