Removal of PO4

[PeterGwee]

You can do larger ones like 80% or so to make things reset better. Or 2x50% a week....there is no limitation.

Regards,
Peter Gwee

[b_goh88]

Thanks guys,

I agree that test results are not the main focus. I did measurement every 2 - 3 days at the inital set up 10months ago and only perform tests on weekly or monthly basis, until this algra problem araise.

My CO2 should not be an issue as I'm using a auto PH control (set at 6.66) for my CO2 and I measure/control KH at 4dH - 5dH, after every WC.

WC is about 30% weekly. Lighting is 4 X 36WPL and 2 X 54WT5 (total 252W, which is estimated 2W per gal) for 8hrs per day.

Plant mess - heavy, until algra issue, which I removed 10 to 20% of the plant together with the blue algra. I will be adding more plant this weekend.

Check using the Redfield Ratio calculator, I either need to reduce PO4 (WC) or increase NO3 (add more KNO3).

Appreciate you could advise what additional things that I need to do. Thanks.

[Aeon]

2 x 50% is only 75% new water. But I think it's good enough considering plants will use up some of the nutrients also.

[b_goh88]

Did another 30% WC yesterday. PO4 remain around 5ppm and NO3 around 20ppm. Did not see anymore Blue Algra. No yellowing but don't seem to be growing well. KH drop to 2.5dH, added sodium bicarbonate to increase to 4dH.

Please advise how to improve plant grow. Thanks.