Can Polyfilter strip Phosphates?

[JayFish4004]

I am in a situation now where even with 25ppm of nitrates in my 20gal Red Sea Max Nano, I still have no detectable phosphates and am curious how. Verified by multiple ICP tests and Hanna Checker.

Tank is almost a year old - feed twice daily, 8 fish and 10 coral. Everything healthy.

Is there a chance that running Polyfilter is completely stripping them out? I keep a small piece in the back chamber with my carbon that I change out biweekly when I do water changes.

I started this because I had elevated aluminum in my first ICP - it has worked beautifully and aluminum is minimal and all other trace metals like lithium and copper were completely stripped.

Am I doing more harm than good leaving polyfilter in when Im not trying to strip anything out?

 

[Jekyl]

Nope

 

[Miami Reef]

Following.

 

[JayFish4004]

Nope

Here is a recent video of the tank - I definitely get algae but nothing I haven’t been able to keep at bay with snails, a tuxedo urchin and some healthy scrubbing. Plenty of coralline algae growth as well. I’ve done 3 ATI ICP test (Nov, Dec, Jan) and all had 0 phosphates.

That was when I had about 10ppm nitrates - now at 20-25 Im still not getting phosphate readings. i will do another ICP test soon mainly to monitor my Iodine dosing, but its very confusing.

Red Sea Max Nano new fish - threadfin cardinals, purple firefish, citron goby, barnacle blenny

youtube.com

 

[Randy Holmes-Farley]

No, polymeric materials will not directly bind any appreciable amount of phosphate from seawater.

I think it unlikely the polyfilter can bind lithium from seawater. Lithium looks just like sodium and potassium that are present at far higher concentration.

I would not use a polyfilter 24/7 unless you have a clear problem. It's removing metals you need.

 

[JayFish4004]

No, polymeric materials will not directly bind any appreciable amount of phosphate from seawater.

I think it unlikely the polyfilter can bind lithium from seawater. Lithium looks just like sodium and potassium that are present at far higher concentration.

I would not use a polyfilter 24/7 unless you have a clear problem. It's removing metals you need.

Good to know! I will stop using ASAP. I put a small piece in an area that doesn’t get much flow, it’s not in the filtration path so it takes more or a passive approach.

Anything on this ATI you would fix that might’ve been a result of 24/7 polyfilter? I’ve got salinity back up to 1.025 and iodine is hopefully in a better spot with dosing .2ml biweekly.

Auswertungsergebnis

ATI Aquaristik - Lab

lab.atiaquaristik.com

 

[Randy Holmes-Farley]

Anything on this ATI you would fix that might’ve been a result of 24/7 polyfilter? I’ve got salinity back up to 1.025 and iodine is hopefully in a better spot with dosing .2ml biweekly.

Auswertungsergebnis

ATI Aquaristik - Lab

lab.atiaquaristik.com

Those are the only two things I was going to comment on. Not sure you'll notice a difference from either one, but it doesn't hurt.

 

[JayFish4004]

Those are the only two things I was going to comment on. Not sure you'll notice a difference from either one, but it doesn't hurt.

Latest ICP and I have completely swung in the wrong direction. Been feeding way too much, but funny it takes about 27ppm nitrates to get my phosphates up. Does this mean I probably should stay around 15-20ppm to have ideal phosphates?

 

[JayFish4004]

Latest ICP and I have completely swung in the wrong direction. Been feeding way too much, but funny it takes about 27ppm nitrates to get my phosphates up. Does this mean I probably should stay around 15-20ppm to have ideal phosphates?

This is from January - 12ppm with 0’s

 

[Randy Holmes-Farley]

As long as nitrate is above 2-5 ppm, I don't think it is likely to be impacting phosphate one way or the other.

 

[JayFish4004]

As long as nitrate is above 2-5 ppm, I don't think it is likely to be impacting phosphate one way or the other.

To me it almost seems there’s a correlation between the two - at least with the food I feed. So if nitrates = x, phosphates = y. How else could we explain 12 nitrates and no detectable phosphates? Obviously as I bring these nitrates back down we’ll see for sure.

 

[Randy Holmes-Farley]

To me it almost seems there’s a correlation between the two - at least with the food I feed. So if nitrates = x, phosphates = y. How else could we explain 12 nitrates and no detectable phosphates? Obviously as I bring these nitrates back down we’ll see for sure.

I'm not sure what you are saying. If phosphate was being consumed (say, by binding to rock), then nitrate might easily get too high by using foods to boost phosphate to detectable levels.

There are lots of relationships between N and P, both in inputs and exports. And several ways each is used independent of the other. But I do not know of any such process that is nitrate-limited at 10 ppm nitrate.

I'd also be wary that P by ICP often does not match P by test kits, for whatever reasons.

 

[JayFish4004]

I'm not sure what you are saying. If phosphate was being consumed (say, by binding to rock), then nitrate might easily get too high by using foods to boost phosphate to detectable levels.

There are lots of relationships between N and P, both in inputs and exports. And several ways each is used independent of the other. But I do not know of any such process that is nitrate-limited at 10 ppm nitrate.

I'd also be wary that P by ICP often does not match P by test kits, for whatever reasons.

Sounds good - Im going to dial back my feeding a bit and circle back next month after another ICP. Corals are loving the nutrients but fearing if I dont act soon algae is gonna become a problem

 

[jp_75]

Sorry to hijack your thread. Is it the filter you would not use 24/7?

 

[mdb_talon]

Sorry to hijack your thread. Is it the filter you would not use 24/7?

From the looks of it that is just a standard mechanical filter pad and I believe is fine to leave in 24/7.

 

[Nano sapiens]

There are systems like yours (and mine) which are fed daily, but phosphate is scavenged/utilized so effectively that no PO4 is measurable in the water column via a standard hobby grade test kit. This is a whole different scenerio than the unfortunate system that is fed very sparcely (or not at all) and thus has undetectable PO4 in the water column and very little to no phosphate getting to the organisms.

With 8 fish in a 20g that are fed well you are seeing the effects in the form of rising NO3 (been there, done that with 5 fish in a 12g). This is largely due to a good amount of ammonia being released by the fish at a rate higher than your coral/other organisms can utilize it and more than your denitrifying bacteria can process into nitrogen/di-nitrogen gas (which mostly dissipates into the air).

In the end effect, the choice is either keep your excess bio load of fish and attempt to mitigate the increasing nitates one way or another or find your system's nitrate eqilibrium starting by a change in the fish bio load.

 

[Nano sapiens]

To me it almost seems there’s a correlation between the two - at least with the food I feed. So if nitrates = x, phosphates = y. How else could we explain 12 nitrates and no detectable phosphates? Obviously as I bring these nitrates back down we’ll see for sure.

How about this. Higher nitrates in this range can slow calcification/growth and the associated need for phosphate. Since less phosphate is being used by the organisms, there is more phosphate in the water column (assuming feeding is kept constant)...which then starts to show up as a PO4 reading on a test kit.

 

[JayFish4004]

There are systems like yours (and mine) which are fed daily, but phosphate is scavenged/utilized so effectively that no PO4 is measurable in the water column via a standard hobby grade test kit. This is a whole different scenerio than the unfortunate system that is fed very sparcely (or not at all) and thus has undetectable PO4 in the water column and very little to no phosphate getting to the organisms.

With 8 fish in a 20g that are fed well you are seeing the effects in the form of rising NO3 (been there, done that with 5 fish in a 12g). This is largely due to a good amount of ammonia being released by the fish at a rate higher than your coral/other organisms can utilize it and more than your denitrifying bacteria can process into nitrogen/di-nitrogen gas (which mostly dissipates into the air).

In the end effect, the choice is either keep your excess bio load of fish and attempt to mitigate the increasing nitates one way or another or find your system's nitrate eqilibrium starting by a change in the fish bio load.

Is there a scenario where my bacteria will catch up to the bioload if I kept feeding how I am?

I was way overfeeding trying to dial in feeding these mandarins, I imagine I can get it under 20ppm by adjusting feeding and not sure I should go lower than that depending on how testing looks

 

[JayFish4004]

How about this. Higher nitrates in this range can slow calcification/growth and the associated need for phosphate. Since less phosphate is being used by the organisms, there is more phosphate in the water column (assuming feeding is kept constant)...which then starts to show up as a PO4 reading on a test kit.

That makes sense - I went from 12ppm to 27ppm in the span of about a month after introducing quite a few more fish. Gonna need to find my new feeding balance.

For the first 6-7 months I fed every other day and lost a fish because of it, never again will I abuse my beloved fish chasing low nitrates, got some bad advice from a ReefBuilders video when setting up my tank and he said he fed an “almost abusive” amount and it got in my head to tey it that way.

 

[Nano sapiens]

Is there a scenario where my bacteria will catch up to the bioload if I kept feeding how I am?

I was way overfeeding trying to dial in feeding these mandarins, I imagine I can get it under 20ppm by adjusting feeding and not sure I should go lower than that depending on how testing looks

I had up to 6 fish in a 12g, but not by choice (an online order got screwed up and I received twice as many fish as expected). I managed nitrate for a few months by increasing my detritus removal/water changes and careful feeding, but it eventually became clear (ever elevating levels of nitrate and other reasons) that I needed to remove a few of them to restore proper balance to the system.

The denitrifying bacteria can be limited by lack of suitable anoxic substrate, phosphate and carbon availability. If I were in your shoes I would first try the most simple thing and add a bio block that has a huge internal surface area for denitrifyers to grow on. Will take a while to see any results, though, since denitrifying bacteria are relatively slow to reproduce.

Choice of food also plays a critical role in how much nitrate builds up (typically the higher the protein percentage, the more potential for increased nitrate).

Protein skimming is also effective against nitrate buildup since it removes a percentage of the system's organics before they can be broken down by nitrifying bacteria into nitrate.

Carbon dosing is a well known and effective technique to lower nitrates (highly recommended to use with a skimmer to remove the additional bacteria). One must be very careful with it as it can drive both NO3 and PO$ to '0' levels quickly if not monitored carefully and the excess bacteria that it creates can slow down pumps or clog pipes (more frequent cleaning is needed to prevent this if it occurs).

There are many other options out there to control excess nitrate such as sulfur dentrifying, methanol denitrifying, refugiums with a ball of chaeto, ATS (algae turf scrubbers), etc. I guess it just depends on how much you want to invest (money and time wise) to keep a lot of fish in a relatively small water volume.