What happened to my PO4...?

AbjectMaelstroM · Mar 7, 2020

So my tank is only 2 months old, though the dryrock was cycled in a tote for 2 months prior. PO4 has been consistently between 0.07 and 0.1 ppm, testing every weekend.

Measured today, was reading 0. Measured again, still 0. I ended up dosing back up to 0.08ppm.

The only thing I'm runing is a skimmer and media cups with floss and carbon. Where is my PO4 going?

No coral and only 2 clowns, fed twice a day with fish frenzy nano and TDO chroma boost.

Params:
SG 1.026
Temp 76f
Alk 7.5
Mg 1450
Ca 450
Ph 8.3
Nitrite 0
Nitrate 10
Ammomia 0

Billldg · Mar 7, 2020

The rock could be absorbing it, being dry rock it is likely absorbing it.

AbjectMaelstroM · Mar 7, 2020

Billldg said:
The rock could be absorbing it, being dry rock it is likely absorbing it.

It's odd that it would start absorbing it now and not over the last 2 months. It's been in the 0.07-0.1ppm range last 8 times I measured.

Billldg · Mar 7, 2020

Maybe, but I don't see any where else it could have gone. P04 doesn't disappear for no reason. The skimmer could have done it, but like you said, why now and not then. On my next tank I plan on using 60 pounds plus of live rock because, though dry rock doesn't have pest, it does come with other issues. My next tank I plan on using 200 pounds of dry rock, but I also plan on using 60 plus pounds of live rock to make sure the proper bacteria is present.

2Wheelsonly · Mar 7, 2020

Couldn’t a higher level of nitrates consume the po4? In all 4 of my tanks early cycle process the po4 bottomed out as nitrates went up before adding fish/corals. Po4 usually is limited early on in my experience.

Randy Holmes-Farley · Mar 7, 2020

Organisms may be starting to grow faster, consuming it.

AbjectMaelstroM · Mar 7, 2020

Now that its been dosed to a controlled amount, going to track it over the next few days and see how things go.

Graffiti Spot · Mar 8, 2020

Be careful adding po4 back to the tank if your not sure the rocks are what’s causing the po4 to drop. Ime newer dry rocks will slowly over time soak up po4 and you won’t notice until you try and lower it, you wil notice it just doesn’t drop or it drops and then goes right back to the level it was on the previous test.

AbjectMaelstroM · Mar 10, 2020

Measured this morning and it's 0.02 so sometjing using/absorbing it. Dosed to 0.06

Reef AquaCult · Mar 10, 2020

Same thing happened to me running a bare bottom, high flow in tank and dry rock. Phosphates always zero unless I feed very heavily. Im not sure I would dose phosphate unless you have coral to feed. You are asking for an explosion of hair algae IMO.

AbjectMaelstroM · Mar 10, 2020

Reef AquaCult said:
Same thing happened to me running a bare bottom, high flow in tank and dry rock. Phosphates always zero unless I feed very heavily. Im not sure I would dose phosphate unless you have coral to feed. You are asking for an explosion of hair algae IMO.

I'll take hair algea over dinos, hehe. Right now it's the only reason why I don't want it to bottom out.

AbjectMaelstroM · Mar 17, 2020

So, these showed up today... The first of what I presume to be the ugly phase of a new tank.

Brown/green splotches showing up on some of the rocks, sand bed and some glass. Assuming this is where my PO4 was going to.

Next question... Do I continue to dose PO4 to maintain detectable levels? I'm trying to avoid dinos but I don't want to be stuck in permanent ugly phase because I'm feeding the algea.

AbjectMaelstroM · Mar 21, 2020

Randy Holmes-Farley said:
Organisms may be starting to grow faster, consuming it.

You were right. My ugly phase seems to have arrived as the rock is turning green/brown and sand bed as well. I've been dosing PO4 to 0.07 every day and its 0 (taken up by algea?) the following morning on Hanna LR. NO3 is going down but much, much slower about 1-2ppm per week.

Should I stop dosing PO4/NO3 as they're just feeding the uglies? I guess my biggest concern is getting dinos from bottomed out nutrients.