Phosphate reduction not working.

[CopperFish]

I had to swap out my tank about 4 months ago (due to impending seam failure) and replaced my almost nonexistent sand bed with a new 1 1/2 to 2 inch sand bed using CaribSea special Grade sand. Ever since, my phosphates have been hard to manage going from an average of .05-.1 to now .68. I tried adding copepods, using lanthium chloride, RowaPhos in an fluidizer and water changes but no matter what I do my phosphates rise back up into this range. One theory I researched is that my rocks are leaching phosphate as they have been in the system for four years since I started the tank, but having a new sand bed might have changed the balance and now phosphate is leaching out of the rocks. Any insights or suggestions would be great, my parameters are below. All corals look healthy except my two Goniapora, not sure why they are struggling. Could be some alk swings or maybe the increased phosphate levels? I guess I'm trying to figure out if this is just my new norm and should be OK with it or if I should continue trying to reduce my phosphate levels to the .05 to .1 range. I just sent in a new ICP test to see if something else is off and should have those results in about a week.

Calcium: 399
Magnesium: 1301
Alk: 7.89
Salinity: 1.26
Nitrate: 3.8
Phosphate: .68
Temp: 78

142 gallon total system. Dosing 40ml/day All for Reef and part b for alk as needed. 20% water change every 2-3 weeks and I use Tropic Marin Pro Reef salt. I feed once a day rotating between frozen brine/mysis and pellet food. I feed the corals twice a week, once with Reef Roids and once with Red Sea AB+.

 

[Randy Holmes-Farley Verified Community Expert]

Copepods won’t noticeably impact phosphate, but GFO and lanthanum will if you use enough. That said, it can take far more to reduce phosphate in a reef tank than in a bucket due to the need to strip it from the rock and sand. Calculators and recommendations are generally only useful to prevent massive overdosing.

 

[slingfox]

Other than water changes, what else do you use for nutrient export?

 

[CopperFish]

Other than water changes, what else do you use for nutrient export?

A Red Sea roller may and skimmer.

 

[CopperFish]

A Red Sea roller may and skimmer.

Mat

 

[James CNM]

Vinegar mIxed with AFR

 

[backbayreef]

WCs and carbon dosing don’t do much to reduce Phosphate, just mostly Nitrate. Like Randy said, it’s either GFO or LC. Given its only 140gal, I would just manually dose PhosphateRx (spread over 2-3 days) and you’re good for months. Note: PhosphateRx is LC-based and some people experienced fish death, particularly tangs. I’ve been using LC-based solutions for more than a decade and have not lost any fish.

Otherwise, the slow (and dirty, imo) method is GFO inside the canister. That has been proven to slowly reduce Phosphate.

Good luck!

 

[James CNM]

WCs and carbon dosing don’t do much to reduce Phosphate, just mostly Nitrate.

Followed Randy's Advice/Experience for a very long time( i won't disclose our ages) Po4 will also reduce...unless i am dosing a stronger solution

 

[slingfox]

I would think about the phosphate reduction journey as two parts.

First, use LC or GFO to reduce the baseline level of phosphate. LC is potentially quicker acting more potent but has some risk for tangs. I have also not been able to reduce baseline phosphate levels level 0.100ppm due to rock leaching into the water column. Specifically, I dosed large amounts of LC into a 25g container with rocks from a tank breakdown and was able to get the level down from 3.000 ppm but could not get it lower than 0.100 ppm.

Second, once you are at or below a new baseline level then you need to either decrease the nutrient import (ie, feed food with less phosphates or just feed less) or increase nutrient export (skim more aggressively, add a refugium or turf scrubber, run GFO or dose LC periodically).

That said, it looks like you mostly have LPS so I don’t think you need to go down to the 0.50-1.00ppm range to have the coral do well.
Plenty of folks run higher levels without any issues.

 

[James CNM]

I feed the corals twice a week, once with Reef Roids and once with Red Sea AB+plus

What are your thoughts using AB+? Do you see any benefits?

 

[backbayreef]

Followed Randy's Advice/Experience for a very long time( i won't disclose our ages) Po4 will also reduce...unless i am dosing a stronger solution

IME, if you’re talking about carbon dosing, NO3 will bottom out prior to making a dent in PO4 since it will continuously leached out from rocks & sand. I’m dosing 25mL/day of vodka on a 550gal system to reduce NO3; but witnessed negligible impact on PO4.

For PO4 reduction, I’m dosing 20mL/day of BW Phosphat-E to keep PO4 in check. Another side effect of LC-based solutions - elevated levels of lanthanum in ICP, not sure if corals are affected though.

 

[James CNM]

LC is potentially quicker acting more potent but has some risk for tangs.

Nvr catch me using that in my display