Phosphate Help

[JohnV8r]

I'm having a phosphate issue in my mixed SPS/LPS reef that seems to be from the sand bed in my display tank being stirred. Phosphates have been at a disappointing .12 the last several weeks since a spike to .5 that was caused by a powerhead blowing 1/4 of the sand bed all over the place.

Yesterday, I had a fighting conch and a monti cap both pinned behind a rock at the very worst location behind my rock stack. My only option was to dig some sand bed to get them out. I also have a Diamond Goby and a large female Maroon Clown that stir up the sand hourly. I'm not entirely surprised by the phosphate spike after the powerhead incident, but I am surprised that it is still at .4 after 24 hours. My nitrates are currently < 1.0 on an Elos test.

I currently run 1.5 cups of BRS high capacity GFO in a Phosban reactor for 196 gallons net volume.

I dose 2.2ml of vodka through dosing pumps throughout the day.

My question is this: I still was not below the desired < .03 phosphate before this latest spike. Should I:

a) increase the amount of GFO I am running,

b) increase the vodka dosing,

c) add vineagar to the vodka to increase the overall carbon dosing, or

d) all of the above

I really want to suppress the phosphates more aggressively.

Thanks in advance.

[bertoni]

GFO will be the fastest way to go. One issue is that the GFO might be exhausted rapidly with that much phosphate in the water column. If the output of the GFO reactor is not measurably lower than the tank, the media needs to be replaced. I'd check that.

Ramping up the carbon dosing might be useful, too. You could try either more vodka or adding some vinegar. If the tank is free of cyanobacteria and other microbial pests, I'd likely just stick with vodka for the moment.

[JohnV8r]

I'm going to check the GFO reactor output water. That's a great idea!

[JohnV8r]

OK, I just ran the output through my Hanna checker and came back with a .13 phosphate level in the output water. Interesting that .12/.13 is where the phosphate level has remained for the last 2-3 weeks.

Is it possible that the BRS high capacity GFO has a limitation such that even when the entire system volume has phosphate at .12/.13 it can't reduce it further? What would limit GFO like that?

I think I'll increase the vodka dosing by 20% and see what happens. Since I have been dosing with a doser in smaller doses throughout the day, I have not had cyano issues like I did when I would dose one large dose once per day.

[bertoni]

Any GFO (for our tanks) can reduce the phosphate level a lot lower than that. If the tank is still a lot higher than 0.14 ppm, I'd give it a bit longer, and see what happens.

Bumping up the vodka dose seems reasonable to me.

Good luck!

[JohnV8r]

I've bumped the vodka dosing from 2.2 ml daily to 3.3 ml daily. That is dosed every six hours in a 3 part RO/DI water to 1 part vodka mixture. Therefore, .825 ml of vodka is dosed every six hours.

I'll give that a couple of days see what happens

[JohnV8r]

OK, it's been a couple of days and the phosphates are down to .11 - .13 based on two tests with my Hanna Checker. The vodka dosing has been increased to a total of 3.3 ml per day dosed in four equal dosings of .825 ml.

I'm going to give this through Sunday afternoon and see where the phosphates are then. However, .12 - .13 was exactly where I was before the spike caused by my digging around in my sand to free the fighting conch and monti cap that wound up wedged behind my rock stack. I don't think I'm overfeeding; one cube of mysis shrimp, one cube of spirulina enriched brine shrimp, and a pinch of Omega One Kelp Flakes in the morning at 6:30 am. The same + a cube of Emerald Entree at 7 pm. 1-2 times a week I feed either a cube of Cyclops or a tablespoon of OysterFeast and PhytoFeast.

What is the next step if my phosphates don't come down? More vodka? More GFO? Add vinegar? Should I thoroughly clean as much of my sand as possible? Remove, clean, and replace my deep sand bed in my refugium?

I'll give you that my Hanna Checker is more accurate than the tests I was using previously. However, I have not had measureable phosphates until I had the powerhead blow 1/4 of my sand around. Now I can't get them back down to immeasureable levels (or at least < .03).

[JohnV8r]

Just to be sure, I checked the phosphates in my return water from my refugium. They are .12 as well.

[bertoni]

That sounds like a lot of food to me, but I'm not sure about the size of the cubes. I might change the GFO media and stop feeding for a few days, to see what happens.

Does the meter measure 0 phosphates in fresh RO/DI? Which model is this?

[JohnV8r]

The food is San Francisco Bay Brand, so the cube sizes differ from mysis to brine shrimp, etc. The food is gone within 60 - 90 seconds max. There are 11 fish for a 175 gallon display tank. I won't rule anything out at this point, but I think my post reads like more food than it actually is. Additionally, I had immeasureable phosphates with the same feeding routine before the sand bed got blown all over.

I can cut the food in half or hold off completely and see what happens, but I honestly don't think food is the source of the problem. It may help it go away, but I don't think it's the source. My only concern with cutting the food completely is the potential stress on the fish, particularly the tangs and anthias.

The Hanna Checker is the HI 713/Phosphate Low Range model.

TDS in my RO/DI water is 0. Phosphates are 0.00

I have to admit, I am baffled. I have had the rock for 4 years. My intuition tells me this has to be coming from the sand bed in the display tank because all of this started when a powerhead became dislodged and blew 1/4 of the sand bed all over the tank. I mean it was everywhere. I had a hair algae bloom almost immediately after and I've been fighting that slowly but successfully (manual removal, hermit crabs, urchin, etc) since the problem began. The hair algae is getting smaller by the week. I just haven't had a vexing issue like this for a long time. All the rest of my parameters are right down the middle of the fairway.

I get a little bit of sand bed movement due to water flow (never will use sugar fine sand again), and some additional turn over from my diamond goby constantly digging under rocks and my maroon clown taking a spot next to my RBTA down to the glass bottom.

I've got chaeto in the refugium, 3.3 ml of vodka dosed daily, 1.5 cups of high capacity GFO from BRS running in a phosban reactor (BRS's recommended amount per their calculator). I'm just going out of my mind with this.

Do I use the siphon gravel cleaner I have and go through the sand tomorrow or should I leave it alone since I think the sand turnover may be the source? I have a lot of rock in my display tank and only about 20-30% of my bottom is actually exposed sand.

[bertoni]

Unfortunately, the time it takes for the food to be eaten isn't important, because what goes in mostly comes back out. Digestion is not very efficient.

I'd probably leave the sand alone at this point, but I'm just guessing.

[Big E]

I wouldn't chase the number down like your trying to do short term. The bacteria levels need to balance out & you keep changing things with vodka dosing & GFO changes.

You kicked up a lot of small granules of detritus all over your tank & gave the algae a chance to get it which caused the bloom.

I wouldn't change anything except start blowing your rocks off & try to trap whatever detritus you can in a filter sock or something similar. It may have caused a bulld up of some detritus in your sump too..........if so siphon, it out.

I get a little bit of sand bed movement due to water flow (never will use sugar fine sand again), and some additional turn over from my diamond goby constantly digging under rocks and my maroon clown taking a spot next to my RBTA down to the glass bottom.


You also have a dusting of phosphate laden detritus on the surface of your sandbed now. You can let these guys work through it or...
Maybe just lightly siphon the bed at the surface so you don't get cyano, ect. If you don't want to siphon you could just use a stick just at the surface to get that detritus stirred up into your flow so it can be exported.

I will take 2-3 weeks but I'm willing to bet that number will work it's way back down.

[swcc]

The other day I was in my backyard wearing sneakers. My roof was replaced a few weeks ago and low and behold I stepped on a roofing nail left over and missed by the clean up. It protruded through my shoe's sole and was digging into my foot when I walked. Not the most comfortable experience and I had a couple options...one would be remove the nail or I could run to the store get some thick shoe inserts that would stop the nail from being able to penetrate into my foot... I chose to remove the nail. Anyways, remove the source is the sensible alternative there, and the same goes for your aquarium. Remove the source of the problem and replace. If the source is taken care of, you are then left with not having to take measures to fix the problems the source is causing. Yes it is a little bit of a days task to remove substrate from a larger tank, but, doing so is the best way towards longevity and of course from the experience you can adjust your husbandry to better maintain the new substrate and drastically lessen or eliminate the situation your experiencing now.

[dviper150]

The other day I was in my backyard wearing sneakers. My roof was replaced a few weeks ago and low and behold I stepped on a roofing nail left over and missed by the clean up. It protruded through my shoe's sole and was digging into my foot when I walked. Not the most comfortable experience and I had a couple options...one would be remove the nail or I could run to the store get some thick shoe inserts that would stop the nail from being able to penetrate into my foot... I chose to remove the nail. Anyways, remove the source is the sensible alternative there, and the same goes for your aquarium. Remove the source of the problem and replace. If the source is taken care of, you are then left with not having to take measures to fix the problems the source is causing. Yes it is a little bit of a days task to remove substrate from a larger tank, but, doing so is the best way towards longevity and of course from the experience you can adjust your husbandry to better maintain the new substrate and drastically lessen or eliminate the situation your experiencing now.

You should see a Dr about that foot. Could get tettani from that nail you stepped on.

[swcc]

You should see a Dr about that foot. Could get tettani from that nail you stepped on.

LOL... Nah it never punctured the skin, just poked the outer layer.

[JohnV8r]

You kicked up a lot of small granules of detritus all over your tank & gave the algae a chance to get it which caused the bloom.

I do blow the sand/detritus off the rocks regularly. However, the problem with sugar fine sand is it ends up suspended in the water column when my diamond goby and maroon clown kick it up due to its size and the flow in my tank. That leads to some of the sand and detritus settling on the rocks...and yes, that one area that gets the most settled sand/detritus is where the hair algae is the toughest to eradicate.

It may have caused a bulld up of some detritus in your sump too..........

You're correct about that. I removed all of my equipment from my sump during a semi annual sump cleaning and got every spec of everything out of the sump, skimmer, etc. shortly after the powerhead incident. The sump is still clean at this point.

I wouldn't chase the number down like your trying to do short term. The bacteria levels need to balance out & you keep changing things with vodka dosing & GFO changes.

That is an excellent point as well. The funny thing about this hobby is that when you reach a certain level of expertise you begin to think you have achieved control. You're right. I need to make adjustments and evaluate rather than shotgunning a bunch of different solutions. I think the fact that my nitrates can be eradicated in a matter of a couple of days makes me less patient about phosphates. Great point.

If the source is taken care of, you are then left with not having to take measures to fix the problems the source is causing.

This is another point that has resonates with me. Removing the sugar fine sand (to the extend possible) and replacing it with medium sized coral sand is on my list of projects. However, that is going to upset the balance in my tank because I will end up stirring up detritus and removing some of the nitrifying bacteria. There will inevitably be a period of adjustment that will take place from the new coral sand being put in the tank. Therefore, I would like to have my parameters back to a stable point so I don't hand grenade the chemistry while it's already less stable than usual. You're right though; I need to remove the source of the problem.

Unfortunately, the time it takes for the food to be eaten isn't important, because what goes in mostly comes back out. Digestion is not very efficient.

As always Jonathan, a well-made point. I'm going to cut the food in half for the next couple of weeks and see if that doesn't help me get out in front of the phosphates. If nothing else, it will accelerate the eradication of the leftover hair algae.

Thanks for your input everyone. I appreciate it.

[swcc]

This is another point that has resonates with me. Removing the sugar fine sand (to the extend possible) and replacing it with medium sized coral sand is on my list of projects. However, that is going to upset the balance in my tank because I will end up stirring up detritus and removing some of the nitrifying bacteria. .

Your forgetting that the bacterial element in your sand is most likely only existing on the nutrients accumulated in your sand in the first place... removing it is the way to go..you can remove it over time vs immediately if your concerned.

[bertoni]

I wouldn't worry about the sand just yet. It's possible that the feeding is the primary problem, even given the history. I ran with sugar-sized sand for over 10 years with no problems, even with a burrowing goby pair.

[JohnV8r]

Here's an update:

I cut the food in half for the last 5 days and was still getting a .11-.13 phosphate reading. I don't think food is my issue.

Yesterday I thoroughly stirred the sand to release any detritus, sucked out about 1/3 of the visible sand (I'm guessing 12-20 lbs was removed from my tank), and did a 30 gallon water change (15%).

This morning the phosphate reading on my Hanna checker was .11 from a water sample taken from the display tank. I checked the output water from my GFO reactor and it was .11 as well. I pulled the 1.5 cups of BRS High Capacity GFO out and put in 3.0 cups of the generic non-high capacity GFO I was using before I switched to BRS High Capacity. 3 cups is the amount the BRS calculator recommended for a non-high capacity GFO (1.5 cups was the recommended amount for high capacity). The GFO reactor output is now 0.02 from the sample from my GFO reactor output.

I don't want to jump to conclusions about BRS's High Capacity GFO. However, here is what my experience has been:

When I switched to BRS High Capacity GFO, my phosphates were .13.

BRS High Capacity GFO was never able to take my phosphates below .11 (Hanna Checker +/- 0.04 accuracy).

During a phosphate spike caused by my digging in the sand to get a fighting conch and a monti cap from behind my rock stack, my phosphates spiked to .5. BRS High Capacity GFO returned the phosphates in my system from .5 to .12. However, the GFO reactor output with the BRS High Capacity GFO was never better than .12.

When I went back to my old non-high capacity generic GFO, my GFO reactor output water had 0.02 phosphates.

Those are just the facts. I am going to reach out to BRS to see if they have any comments, recommendations, and/or if they do any regular quality control on their GFO batches. BRS High Capacity GFO is expensive compared to non-high capacity GFO and at this point I'm uncertain that it performs as advertised.

I would certainly invite any representative from BRS to respond to this thread.

[tankmates]

I have EXACT same problem, same GFO, almost same food source and same diamond goby :).....few days back I got excellent advise from betroni...cut my food ...but started changing GFO every 2 days..within last 5 days...my phosphates are .06 from .18......I think you should also change GFO every couple of days till you get it to level where it is under control and then leave it for longer period....Just what is working for me..I did GFO change couple days back...then my phosphate was .12, now I am doing one more on saturday.

[JohnV8r]

That is why I swapped out the BRS GFO today and put 3 cups of my other GFO in my GFO reactor today.

The only thing that has me scratching my head over the BRS High Capacity GFO at this point is that I have never been able to get output from my GFO reactor with the BRS High Capacity GFO that was lower than .12. Even when my phosphates in my display tank were .13 on my Hanna Checker and the BRS GFO was fresh.

To put my old generic non-high capacity GFO (that costs about half the BRS HC GFO) in my reactor and have the phosphate in the reactor output immediately drop to .02 has me wondering out loud how good the BRS HC GFO really is. I emailed BRS and asked for their feedback this morning. I have not received a response to date.

[novazul1]

Try put some bacteria additive....I got same problem before and it will speed up the process

[bertoni]

If the phosphate is leaching from the sand or the live rock, this problem might take a while to resolve. Could you post a picture or two of your sandbed?

[JohnV8r]

I'll be happy to take some pictures. However, my phosphates in my display tank are 0.04 this morning. GFO reactor output is 0.02. It's been less than 24 hours since I changed the BRS High Capacity GFO out of my system and put in 3 cups of my LFS' generic non-high capacity GFO.

Since BRS has not responded to my email asking for feedback and direction on why I was not able to get my phosphates below .11-.13 with their "premium" GFO product, I will be calling them for feedback today. I still have plenty of the BRS High Capacity GFO to see how it performs now that I have the phosphates back to the level they were previously.

[Bluecorals]

Are you still dosing vodka or vinegar in your system to help maintain phos level low?

[Tuton]

If you want to get your phosphates down to undetectable levels you should run phosphate sponge by Kent marine. I put it in a high flow area of my sump on friday and take it out on sunday. I never have any phosphates and I don't run GFO.

[tankmates]

I also find that HIgh capacity GFO from BRS does no good...as soon as i went back to regular GFO from them..phosphates were lower in the past..

[JohnV8r]

Yes, I am dosing 3.3 ml of vodka per day (.825 ml every 6 hours) through a BRS doser.

[JohnV8r]

@Tuton: I have used Kent Phosphate Sponge in the past to pull down spikes. However, per the instructions that product is designed to be used for no more than 24 hours. If it remains in your system for more than 24 hours, it releases the phosphate back into your system.

[JohnV8r]

Here's an update:

I had a very nice conversation with Brandon at BRS. Brandon read through this thread prior to our conversation. We had an additional conversation to fill in any gaps in the details about what is going on. After reviewing everything from the thread, what has happened, the measurement differences between the GFO reactor output levels between the two GFO sources, food amounts, and all details, Brandon agreed that this is a unique situation and I am not crazy. LOL!

He explained three things to me that were of value: First, BRS' High Capacity GFO is rated to take twice as much phosphate based on the fact that it has more surface area for phosphate ions to bind to than regular GFO that has smaller granules. It is not necessarily a chemically stronger GFO than the non-High Capacity.

Second, GFO is produced in the United States to remove arsenic from water sources. Because of the critical safety purpose GFO is used for, its production is fairly well regulated. That said, BRS receives shipments in 4000 lb lots and it is possible (possible, not probable) that there could be a slight variation in the consistency of the GFO when distributed from a 4000 lb lot to a 1.75 lb container. A 4000 lb lot that is set up to perform at a particular level can have variances in its individual parts that don't affect the sum performance.

Third, leaching of phosphate from coral (calcium carbonate) rock at aquarium hobby PH levels is not very likely. Any phosphate in coral rock would be trapped at saltwater aquarium hobby PH levels (leaching of phosphates from trapped detritus in sand is another story).

The next step is that when the current non-BRS GFO is spent I will replace it with the remaining BRS High Capacity GFO that I have to see what happens with its performance.

I do want to say that I was very pleased with the response from BRS and the time Brandon took to understand the issue and my concerns.

[bertoni]

I disagree about the phosphate leaching from live rock, although it's possible that what we see might be the effects of detritus. People ran tanks with no sand at all, and still see the full range of phosphate problems.

[JohnV8r]

I'm just the messenger on this one.

I hope to god I don't have phosphate suddenly leaching out of my rock stack after having had this rock with no phosphate problem since 2007 and no issue until the powerhead blew my sand all over.

[ampemployee1]

I have EXACT same problem, same GFO, almost same food source and same diamond goby :).....few days back I got excellent advise from betroni...cut my food ...but started changing GFO every 2 days..within last 5 days...my phosphates are .06 from .18......I think you should also change GFO every couple of days till you get it to level where it is under control and then leave it for longer period....Just what is working for me..I did GFO change couple days back...then my phosphate was .12, now I am doing one more on saturday.

I think the approach makes sense if you are checking the output of your reactor, and its no longer lower than the input phosphate levels. Personally, I run my GFO in a filter sock in the sump. Periodically, I take the sock out with some tank water let it sit in a container for 30 minutes and test to compare against the readings I'm getting from the main system. If the phosphate levels are the same its time to change the media. It takes the guess work out of whether its time to change this very expensive media.

Good luck with getting your levels down. I'm fighting a similar battle as well.

Cheers, Ed

[swcc]

brs is correct the rocks are not leaching(unless ph is low enough to dissolve calcium carbonate)... the bacterial processes and phosphate bound to the rock can cause a problem though. phosphate prblems from rocks is from bacterial processes and flux. if the rock has plenty of phosphate when bacteria die the live bacteria do not need their phosphate as it is in abundance so do not recycle it and the dead bacteria get discarded thus producing the shedding. so if one has rock loaded with nutrients it will shed more than one very limited in nutrients. considering when you touched the sandbed you developed the phosphate issue your particular dilemma is your substrate.

[bertoni]

brs is correct the rocks are not leaching(unless ph is low enough to dissolve calcium carbonate)...
Do you have any data to show that's true? Randy has said the opposite many times, and he's a chemist and has studied a lot of issues in reef chemistry.

[swcc]

Do you have any data to show that's true? Randy has said the opposite many times, and he's a chemist and has studied a lot of issues in reef chemistry.
when did he say this?... it is important to understand his chemistry takes on many aspects were corrected/completed by marine biology/microbiology on the matter... unfortunately most of these discussions are gone. Basically, a chemist is not a biologist and chemists tend to ignore biological happenings and thus not paint the complete picture. You have been around long, so, you may perhaps remember discussions on the matter back in the day. I am recollecting.
Either way you want to look at it, the results are that nutrient rich rock will in fact increase phosphate into an aquarium. Be it chemically or biological. If I am wrong, no biggie. But I believe biology first, chemistry second.
Only way Randy could prove it is purely chemical is to have completely sterile rock, submersed in completely sterile salt water and then observe this phosphate leaching. Unless you have data showing he did this, it is biological that he is explaining from a chemistry standpoint.

[bertoni]

You can search and find probably a hundred or more threads where we discuss the release of phosphate from rock. It seems quite well established to me, and I don't see what biology has to do with it. The issue is that phosphate fits reasonably well into the calcium carbonate matrix. I don't see how biological processes could result in all the phosphate problems we see.

[JohnV8r]

I'm happy to report that my phosphates this morning are officially 0.00 in my display tank. The output water from my GFO reactor is also 0.00. Given that the Hanna Checker has an accuracy of +/- 0.04, I'll simply take that as an indication that I am back to where I want to be. The polyp extension on my milliporas, montis, and acros is back to being what it should be. Qualitatively, everything looks great.

My next step will be to give the remaining BRS High Capacity GFO another try when the current generic LFS non-high capacity GFO expires or I reach the four week point of having it in my GFO reactor. I'll report those findings/readings when I have them.

I do want to be fair and reiterate that Brandon at BRS could not have been any nicer or more pleasant to deal with. He seemed genuinely concerned about my experience with the BRS GFO product and I will report my second experience with their High Capacity GFO product back to them once I have the information.

Finally, I did some math to try to better understand the value of using the BRS High Capacity GFO, assuming it works as well as advertised. The difference in the cost of using BRS High Capacity GFO vs BRS regular capacity GFO was somewhat surprising.

If I purchase HC GFO by the gallon (16 cups) and use 1.5 cups at a time in my reactor per BRS's calculator, each 1.5 cups costs me $16.98. If I purchase non HC GFO from BRS by the gallon and use 3 cups at a time in my reactor per BRS's calculator, each 3 cups costs me $11.63.

That means using BRS HC GFO to achieve the same results as their non-HC GFO costs 31.5% more when purchasing in 1 gallon quantities. That more than anything may dictate which product I use moving forward.

I'll let everyone know what the BRS HC GFO results are once I have swapped out my current GFO for the BRS HC GFO.

[tankmates]

I do blow the sand/detritus off the rocks regularly. However, the problem with sugar fine sand is it ends up suspended in the water column when my diamond goby and maroon clown kick it up due to its size and the flow in my tank. That leads to some of the sand and detritus settling on the rocks...and yes, that one area that gets the most settled sand/detritus is where the hair algae is the toughest to eradicate.



You're correct about that. I removed all of my equipment from my sump during a semi annual sump cleaning and got every spec of everything out of the sump, skimmer, etc. shortly after the powerhead incident. The sump is still clean at this point.



That is an excellent point as well. The funny thing about this hobby is that when you reach a certain level of expertise you begin to think you have achieved control. You're right. I need to make adjustments and evaluate rather than shotgunning a bunch of different solutions. I think the fact that my nitrates can be eradicated in a matter of a couple of days makes me less patient about phosphates. Great point.



This is another point that has resonates with me. Removing the sugar fine sand (to the extend possible) and replacing it with medium sized coral sand is on my list of projects. However, that is going to upset the balance in my tank because I will end up stirring up detritus and removing some of the nitrifying bacteria. There will inevitably be a period of adjustment that will take place from the new coral sand being put in the tank. Therefore, I would like to have my parameters back to a stable point so I don't hand grenade the chemistry while it's already less stable than usual. You're right though; I need to remove the source of the problem.



As always Jonathan, a well-made point. I'm going to cut the food in half for the next couple of weeks and see if that doesn't help me get out in front of the phosphates. If nothing else, it will accelerate the eradication of the leftover hair algae.

Thanks for your input everyone. I appreciate it.

Just a note here as I did almost same, replaced sugar fine sand with coarse grade coral...make sure you remove the sugar sand well...because my diamond goby still churns out that sugar sand particles into the water, even though those are very less..I am going barebottom with my new tank..

[swcc]

You can search and find probably a hundred or more threads where we discuss the release of phosphate from rock. It seems quite well established to me, and I don't see what biology has to do with it. The issue is that phosphate fits reasonably well into the calcium carbonate matrix. I don't see how biological processes could result in all the phosphate problems we see.

because it is the bacteria utilizing the phosphate bound to the calcium carbonate(then die-off and subsequent shedding)... you can find plenty of discussions on this matter. Saying the 'rocks are leaching phosphate' is just a simplified way of describing what is actually happening and it is happening due to bacteria and their processes on the rock.
for instance... notice what is going on when one 'cooks' their rock, bacterial processes utilize the bound phosphate and thus clean the rock of said phosphate. Drop some dry rock in a bucket of clean salt water and it won't just rid itself of bound up phosphate and leach into the water.
Perhaps your misunderstanding this... all I am saying is technically BRS is right the rocks are not just releasing phosphate into the water...but that does not mean the bound phosphate in the rock is not actually an issue. It very well can be.

[bertoni]

Why do you think that bacteria are required to remove phosphate bound to the rocks? Chemically, I don't see the basis for that statement.

[JohnV8r]

I have decided to make a change in my plans to test the BRS HC GFO. I swapped out my LFS' generic GFO this morning and replaced it with 2 cups of BRS HC GFO. I started thinking a better test might be to test how long the BRS HC GFO could produce a 0.00 - 0.04 reading on my phosphates since the LFS' GFO took the phosphates down to 0.00 in four days.

I'll report back what I find.