PO4 at 40ppm!!

["Lee Boon Chuan" <lee.bc at ellipsiz_com>]

Hi guys,

Yesterday I tested my water and I found PO4 was at ridiculus level.

PO4	40ppm!!
NO3	20ppm
Fe	0.5ppm

The last test I done was about 3~4 weeks ago.
PO4	0.5ppm
NO3	10ppm
Fe	0.25ppm

I tested the test kit by getting reading from my tap water and some distill water.  They turn out ok, so the test kit should be reliable.

I remembered adding some plant tabs into the substrate about 2 weeks ago.  I did some replanting last week.  I checked the composition of the tabs and found it contains "soluble phosphate" while only part of the N is in the soluble form.  I think that's why the PO4 shot up while the NO3 is still in the reasonable range.

So far, there is no algae outbreak.  In fact the plants are starting to have tremedous growth especially the Hydrocotyle while there is no sign speeding up of algae growth.  And my Echinodorus ozelot is sending out a flower stalk to the surface.

According to the posts in which Tom Barr has shared his findings about algae vs plants, there should be little risk of algae outbreak if the plants are kept in healthy condition.  I am keeping my tank in this way to see how things go.  I would like to see if the P limitation theory can be thrown right out of window.

I do have one concern.  Will PO4 at this level have any other negative impact of my plants or fishes?

BC (Singapore)