Why are my phosphates dropping?

[Reefing.with.Rich]

I have a 26g Red Sea max nano peninsula
2 clowns,2 mandarin dragonets,5 Nassarius Snail, 2 Trochus Snail, coral banded shrimp, and a bunch of coral lol
I feed heavy daily(pellets,live brine,ab+)
I’m running no GFO either

1-20-23 0.39
1-22-23 0.37
1-29-23 0.15
2-5-23 0.11
2-6-23 0.1
2-7-23 0.08

 

[FlyinAg]

How are you testing?

Filtration?

Water change schedule?

Dosing anything like bottle bac?

I have a hard time keeping mine up but that's a big jump if the test results are indeed accurate.

 

[Reefing.with.Rich]

How are you testing?

Filtration?

Water change schedule?

Dosing anything like bottle bac?

I have a hard time keeping mine up but that's a big jump if the test results are indeed accurate.

Hanna testers

Filter sock, bag of red sea carbon, life rock, live sand, marine pure biomedia spheres

Auto water change-1g per day

Dose microbacter7 once in a while just to assure enough bacteria

 

[anthonymckay]

Auto water change-1g per day

That might be your answer? 26g minus the displacement of rocks and filter media... 1/26 of 0.36 is 0.015 you're removing each day. You're dropping about 0.01-0.02 each test. I'm not entirely sure that's why, but just a guess. Also possible that the 0.39 and 0.37 results were just bad results... sometimes that happens with hanna testers.

 

[gbroadbridge]

I have a 26g Red Sea max nano peninsula
2 clowns,2 mandarin dragonets,5 Nassarius Snail, 2 Trochus Snail, coral banded shrimp, and a bunch of coral lol
I feed heavy daily(pellets,live brine,ab+)
I’m running no GFO either

1-20-23 0.39
1-22-23 0.37
1-29-23 0.15
2-5-23 0.11
2-6-23 0.1
2-7-23 0.08

Are you carbon dosing?

 

[Reefing.with.Rich]

That might be your answer? 26g minus the displacement of rocks and filter media... 1/26 of 0.36 is 0.015 you're removing each day. You're dropping about 0.01-0.02 each test. I'm not entirely sure that's why, but just a guess. Also possible that the 0.39 and 0.37 results were just bad results... sometimes that happens with hanna testers.

Are you carbon dosing?

I have a small bag of Red Sea reef spec carbon to keep the water clear

 

[Reefing.with.Rich]

That might be your answer? 26g minus the displacement of rocks and filter media... 1/26 of 0.36 is 0.015 you're removing each day. You're dropping about 0.01-0.02 each test. I'm not entirely sure that's why, but just a guess. Also possible that the 0.39 and 0.37 results were just bad results... sometimes that happens with hanna testers.

From all the info out there water changes don’t do much to lower ohosphate
Before my versa pumps came in I was doing 20% water change weekly and the phosphates were pretty consecutive I feel

 

[gbroadbridge]

From all the info out there water changes don’t do much to lower ohosphate
Before my versa pumps came in I was doing 20% water change weekly and the phosphates were pretty consecutive I feel

Well if you remove 10% of the water, you are removing 10% of the phosphate in the water column.

However, phosphate binds to carbonate surfaces such as rock and coral and they sit at equilibrium with the water, so the rock then releases phosphate back into the water.

That is why phosphate removal is difficult once it has accumulated.

It is quite possible that your coral are consuming more phosphate than you are feeding into the tank which together with water changes would explain the slow drop.

 

[ptrick21186]

How old is your tank?

 

[Reefing.with.Rich]

Well if you remove 10% of the water, you are removing 10% of the phosphate in the water column.

However, phosphate binds to carbonate surfaces such as rock and coral and they sit at equilibrium with the water, so the rock then releases phosphate back into the water.

That is why phosphate removal is difficult once it has accumulated.

It is quite possible that your coral are consuming more phosphate than you are feeding into the tank which together with water changes would explain the slow drop.

Thank you

 

[FlyinAg]

Yeah I say start with making sure tests are accurate (my ULR phosphorus hannah can be a pain) ensuing the cuvettes are clean and water isn't full of particulates that can slew results. Keep testing and reduce the water changes. If you are changing a gallon a day that adds up over the week and month. See if that helps.

 

[anthonymckay]

So I just stumbled across some other thread on a ReefMoonshiners group where Andre (the RM creator) was mentioning that high silicates in the water can result in incorrectly high phosphate test results. Would be good at this point to get an ICP test done to determine if a) you have possibly high levels of silicates in your RODI water, or b) if the phosphate test results you're getting are close to what ICP reports? High silicates could be an explanation for why you were getting 0.39 po4 results.

Also curious, any chance you opened a new box of phosphate reagent to use between 1/22 and 1/29 tests? I've previously had instances where I was getting unexpected results with my hanna nitrate checker, and then tried a new box of reagent and suddenly it was testing at the levels I expected to see. Sometimes you just get bad batches of reagents.

 

[Reefing.with.Rich]

How old is your tank?

So I just stumbled across some other thread on a ReefMoonshiners group where Andre (the RM creator) was mentioning that high silicates in the water can result in incorrectly high phosphate test results. Would be good at this point to get an ICP test done to determine if a) you have possibly high levels of silicates in your RODI water, or b) if the phosphate test results you're getting are close to what ICP reports? High silicates could be an explanation for why you were getting 0.39 po4 results.

Also curious, any chance you opened a new box of phosphate reagent to use between 1/22 and 1/29 tests? I've previously had instances where I was getting unexpected results with my hanna nitrate checker, and then tried a new box of reagent and suddenly it was testing at the levels I expected to see. Sometimes you just get bad batches of reagents.

I have 3 boxes of the reagent so maybe I’ll check another box and see how that goes. As for the silicates, I tested my rodi water myself and came up with 0 silicates
Along with my api test I sent in

 

[Reefdiculous22]

So I just cam across this issue as well. My phosphates have been running between.1 and . 2 for the past six months. I did my water change today and my phosphates were.04. I just picked up a new box of reagent yesterday exp date of 2026. It read .06. So my phosphates have def dropped. My nutrients are around the same. They generally run between 15 and 25 ppm. Using the Hanna checker as well.