Phosphates. How Low is Too Low

[AKL1950]

NO3. 7.0
PO4. 0.01
PH. 7.98
Salinity. 34.7
Temp. 79-80
Alk. 8.4
Ca. 530
Mag. 1580

My tank is going on 5 months now. Went through an initial diatom phase that cleared itself up. I started introducing corals last month, so have increased the lights to accommodate them. Expected result is an increase in algae. Don’t think it’s all diatoms, but probably additional hair algae on the rocks. Snails and tangs are keeping it in check, but my concern is my phosphates. NO3 is running around 7.0 and phosphates are running at 0.01. Is that too low on the phosphates. Hard to see in the pictures, but it’s sort of fuzzy algae on the rocks about 1/8” tall and looks like hairs.

the rocks are using it up. Also get a good bit of diatom on the glass.

should I be worried, or is it just running through a normal phase of maturing.

 

[Quietman]

I've always shot for 'detectable phosphates'. As long as there's some color change however faint, it's seemed to be ok in my tank. Now if you combine barely there phosphates with barely there nitrates you can run into issues with unwanted organisms out competing desirable (or manageable) organisms. For example 0/0 N/P can lead to dinos out competing GHA for instance. You don't want too much GHA but you really don't want any dinos.

 

[dstockwell]

You sure Phosphate is 7.0 and not .7, either way phosphate is high. Should be .0#

 

[AKL1950]

You sure Phosphate is 7.0 and not .7, either way phosphate is high. Should be .0#

No,no. Nitrates are 7.0 and phosphates are 0.01.

 

[dstockwell]

Sorry my mistake, then .01 - .07 is fine.

 

[Randy Holmes-Farley]

IMO, less than 0.02 ppm phosphate is too low for a reef tank.

 

[AKL1950]

IMO, less than 0.02 ppm phosphate is too low for a reef tank.

Randy, I’m feeding pretty good. I am running UV, Skimmer and filter sock. Only changing about 5% water a week. What would be some good options to help the phosphates rise a little Without over doing it. I am assuming that since I’ve increased the lights for the coral additions, that has caused the increase in algae which is increasing their nutrient consumption and causing the lower NO3 and PO4. Would that be a good assumption? How best to counter it?