Why after feeding Hanna URL Phosphorus Checker still shows zero

[WVReefJunkie]

So my P04 was .003 Phosphate, and I fed the tank. It then measured .03 Phosphate, I checked the next day, it measures zero. I fed the tank again, and still reads zero. Any ideas, I took the Gfo reactor offline, and Iam currently dosing Nopox 15 ML per day on a Neptune Dos. N03 is around 20ppm.

 

[Saltyreef]

Phosphate absorbs into the rocks and until it reaches equalibrium with your water you wont consistantly be able to test the free p04 in the water.

 

[Sam816]

what's ur tank volume? what's your coral density? redsea suggests 3 ml of nopox for 25 gallon which in my opinion is high. it will neutralize phosphates quickly.

 

[WVReefJunkie]

400 gallons total water volume, I have six acro frags, 1 scoly, 3 torches, 1 Frogspawn. I started way below the recommended dose for Nopox, started around 8ML and Iam up to 15 ML now, been dosing for about a month and a half. N03 hasnt dropped any.

Salty Reef, so you are talking about inorganic and orangic forms of P04, correct. So Iam only able to test one of theses forms, I shouldnt worry about stressing of my corals?

 

[Sam816]

how are your corals doing? are they stressed?
any particular reason why you want to up your phosphates? or are you trying to bring your nitrates down?

 

[WVReefJunkie]

how are your corals doing? are they stressed?
any particular reason why you want to up your phosphates? or are you trying to bring your nitrates down?

Yes, trying to bring N03 down to the 5-10pp range to see if I could improve colors. I have never had any issues with P04 dropping to zero, usually would be .03-.06 phosphate.

 

[Sam816]

if you want to lower your nitrates only then you should taper off the nopox as it will lower both. add purigen or nitrate specific additives.
ideally i will let the tank reach its equilibrium while keeping nitrates in check. don't add new live stock or change feeding regimen. pods will grow according to available food and reach a level where everything will be in equilibrium.

 

[WVReefJunkie]

I would like to control N03 & Po4 with Nopox only, I would like to get rid of GFO media. I put 16 cubes of Mysis and two sheets of Nori, and my reading just showed 3ppb or .009 Phosphate. I have about seventeen fish in my system currently.

Unicorn Tang 9"
Vlamingi 8"
Blue Tang 5"
Chocalate Tang 5"
Yellow tang 4"
Purple Tang 4"
Atlantic Blue 4"
Sohol Tang 3"
2 Gold Nuggets
3 Lyretail Anthias
Six Line
Yellow Coris
2 Common Cleaner Wrasses

 

[Sam816]

you can control both once they reach a certain controllable level. right now you have almost no phosphate to control.
I think your nitrate reduction is hindered because of no phosphates. take out half of GFO media now & remaining half after a week or two. second option, try dosing phosphates and see if it helps reduction in nitrates. do one thing at a time i.e. either take out GFO or dose phosphates.

 

[WVReefJunkie]

Thanks for helping me, I took the GFO offline today, I will see what p04 does with no gfo and feedings. Then if it doesnt come up, I have some Neophos I could dose.

 

[landlubber]

likely because measurable levels arrive when the fish poop not when the food enters the water. maybe a little coffee and a cigarette to inspire them