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Phosphate RX - Lanthanum chloride dosing while PO4 and NO3 are 0

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I have hair algae on the rocks. It accumulated on my rocks cuz of negligence over the summer .  Currently both Nitrate and Phosphate read 0 but that’s not the case. ELOS tests. 

I know the Phosphate is released in the water by the rocks slowly. 


Since I have a 0 reading of Phosphate, how can I dose Phosphate RX? I started last night with a half dose .

6 drops in 10 gallons will cut the Phosphate down by 0.5ppm.

I did 6 drops in almost 25 gallons of total water volume. 


I just need some guidance on how to proceed going forward since my tests will always show 0 and I don’t have a number as a guide for dosing .

Thanks !

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po4 is adsorbed to aragonite just like it is w/gfo.  you can't stop or prevent this with any product.


you want coraline algae and corals on that space so pest algae has less space to settle and grow.  


without that cover, algae will settle and grow regardless of dissolved nutrient levels...and it will be completely up to you and the rest of the cleanup crew to control.


(And unless your test kit is broken/out of date it is not lying)

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Thanks mcarroll I’ve been dosing nitrates and Phosphates to keep the levels up and after a 4 day blackout to kill dinos I found out Phosphates bottom out fast and I have to dose to keep it detectable at the 0.03 mark.

Nitrates have somewhat leveled out at 4-5ppm. They used to be 0 as well.


Phosphate RX was a big mistake.

I assumed my Phosphate was high since I had a bad test kit and bottoming it out with lanthanum chloride along with 0 nitrates resulted in a nasty dinoflagellate outbreak.


Since then I had bought good test kits that actually measure something.


Hoping that keeping the levels up will keep the dinos away. That is until an even uglier strain that is ignorant to NO3 and PO4 elevated levels shows up.

Knock on wood that will not be the case.

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