Sydney's phosphate problem !

Not sure if anyone experience's the same problem but, if you get a bit of algae growing in your tank there is a good chance there is phosphate in your tap water in minute quantities.

I mean if you are in the habit of regularly changing your water yet you notice that you still tend to get a bit of algae then it might be worth testing your tap water for Phosphate.

Here is the scenario:

I have been setting up a planted tank for a 8 months now; spec's are:

150 Litres roughly
96 watts of Plant specific lighting - running 8 hours daily.
a canister filter running - bio balls, matrix, filter wool, purigen...
10 neon's, 5 rasboras, 2 angels, 2 octoclinclus (probably a bit overstocked .... I know)
Nitrate - almost 0ppm
Fully cycled
a whole host of plants + Japanese hair grass and long hair grass (going for that Japanese planted tank look but, a long way off )
Using Sea chem Excel to dose CO2

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Problem was this slimy blue green algae or flagellate looking goop - consistency was very slimy when you rubbed it between your fingers and, it had an affinity for the plants leaves and rocks.
This was terribly frustrating as I tried everything to get rid of it i.e. feeding less regularly, decreasing lighting, water changes, scraping the algae ....so pretty much everything short of taking everything out cleaning it with chlorine which someone suggested ... also dosed the crap out of the tank with Excel. Still to no avail.....

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Kept trying to figure out how this algae would have any nutrients to survive .... i mean I wasn't feeding the fish regularly, I did frequent water changes and no luck...

I decided I will get the full test kit out and re-check everything and, surely enough the phosphates were quite high! arrrggghh so I had to determine the source of the nuisance and, so I tested the tap water which I use to top up the tank and BINGO my tap water registers a reading of 0.5ppm phosphate ! so I guess this residual phosphate in the tap water has built up in the system leading to a excessively high reading of Phosphate (and the compounding fish waste of course) :<>