Dry rock (Marco rock) and phosphate issues

[oogie]

I have recently setup a tank with dry "Marco rock", ammonia source and bottled bacteria for the first time.  In the past I only used live rock to startup my tank.  What I am noticing is, nitrates are accumulating as ammonia source is processed to nitrate, phosphate remained 0.  After cycling, I added all zoanthids I had in other tanks in to my new 4 gallon pico with Marco rock.  At this point I started to dose phosphate and when I test after dosing with Hanna Checker ULN, it register about 0.05 ppm.  But within 12 hours, it drops back to near 0.  So I dose again to 0.05 ppm, 12 hours later back down to near 0.   its been over 2 months repeating this.  So only reason I can come up with is,

 

1,  I have too much zoanthids in relation to water volume which sucks up phosphate quickly.

2. Marco rock is absorbing phosphate as curing process

3. Combination of 1 and 2 above

 

Can you guys share your experience with Marco or other dry rock and phosphate issues?

 

Thanks in advance!

[Staticmoves]

if you check out my tank re-set, I had the same issue (with P04 and N03), until rock seasons up and reaches equilibrium.

then I have had to stop dosing both. ( I know your situation is high N03 ).

your live rock in the past was already saturated and seasoned.

Now, that being said, you have a much smaller vol of water, so sensitivity is going to be exponentially increased.

I also experienced low Alk in the beginning with my dry rock.

it took about  6 months for my rock to reach that nutrient equilibrium. 

Saw some pictures in your tank thread, and it looks great.

 

My 2 cents.....

[oogie]

12 minutes ago, Staticmoves said:

if you check out my tank re-set, I had the same issue (with P04 and N03), until rock seasons up and reaches equilibrium.

then I have had to stop dosing both. ( I know your situation is high N03 ).

your live rock in the past was already saturated and seasoned.

Now, that being said, you have a much smaller vol of water, so sensitivity is going to be exponentially increased.

I also experienced low Alk in the beginning with my dry rock.

Saw some pictures in your tank thread, and it looks great.

 

My 2 cents.....

Thanks for your reply!

My nitrate are actually at a level I would like to keep it for zoa only tank. Around 0.15.

Thanks in advance!

[Staticmoves]

2 minutes ago, oogie said:

Thanks for your reply!

My nitrate are actually at a level I would like to keep it for zoa only tank. Around 0.15.

How long did it take to stabilize?

Thanks in advance!

around the 6 month mark I believe.

believe it or not, I have been having good luck with my dry rock this time around.

though I did change my method for seasoning from previous attempts. (Knocking on all kinds of wood.........🌲)

[oogie]

1 minute ago, Staticmoves said:

around the 6 month mark I believe.

believe it or not, I have been having good luck with my dry rock this time around.

though I did change my method for seasoning from previous attempts. (Knocking on all kinds of wood.........🌲)

Great! I guess this is better then getting tons of phos/nitrates from dead stuff on live rock and going thru horrible "ugly stage".  

[mitten_reef]

1 hour ago, oogie said:

Great! I guess this is better then getting tons of phos/nitrates from dead stuff on live rock and going thru horrible "ugly stage".  

fyi, dry rock starters tend to encounter more issues with dinos due to this phosphate "sink" issue sucking all phos from the water, creating favorable conditions for dino. 

if you keep up with the dosing/monitoring, it may not happen. 

[oogie]

6 hours ago, mitten_reef said:

fyi, dry rock starters tend to encounter more issues with dinos due to this phosphate "sink" issue sucking all phos from the water, creating favorable conditions for dino. 

if you keep up with the dosing/monitoring, it may not happen. 

Thanks for the comment.   Yes! No Dinos foe me! 'Knock on wood'

[seabass]

There's nothing wrong with what has been said.  However, phosphate binds to the calcium of your new rock and sand.  If the rock was created in a low phosphate environment (like that on most natural reefs), the rock (and even the sand) will have the ability to bind a considerable amount of phosphate on its surfaces.

 

I assume that it eventually reaches a point where the concentration of phosphate on the rock is equal to the concentration of phosphate in the water.  At this point, the rock will stop binding additional phosphate.  It even has the ability to leach phosphate into water which has a lower concentration.

 

Of course, algae will utilize the phosphate on your rock, along with the nitrate in your water (note that nitrate doesn't bind to calcium).  This provides algae a source of nutrients, even when the concentration of phosphate in your water is low (even undetectable).  I assume that this situation (where the concentration of phosphate is higher on the rock than in the water) favors algae growing on the rock, over corals which take most of the nutrients from the water column.

 

IMO, the best thing to control this algae growth is a good cleanup crew of reef-safe herbivorous snails (and crabs).  Coralline algae will also help deter other forms of algae from growing on top of it; and coral will also be competing for space and light.  This is part of the battle with algae that us reef keepers continue to wrestle with.

[oogie]

Seabass! Nice to hear from you!

Thanks for explanation! So many things changed from old days huh?

[seabass]

I was like, wow, cool, oogie is here.  Yeah, things have certainly changed.  We used to shoot for undetectable phosphate levels.  Plus, live rock from the Pacific was the norm.  Now it's mostly dry rock, LEDs, and all-in-ones.  I kind of miss the old days; I just wish I knew then, what we know now.

 

Good to see you around.

[oogie]

2 hours ago, seabass said:

I was like, wow, cool, oogie is here.  Yeah, things have certainly changed.  We used to shoot for undetectable phosphate levels.  Plus, live rock from the Pacific was the norm.  Now it's mostly dry rock, LEDs, and all-in-ones.  I kind of miss the old days; I just wish I knew then, what we know now.

 

Good to see you around.

Haha yeah! I couldn't belive I am actually dosing phosphates! 

[Staticmoves]

6 hours ago, oogie said:

Haha yeah! I couldn't belive I am actually dosing phosphates! 

Keep a close eye on testing. 
my situation, if I’m not mistaken, I only had to dose PO4 for a few months, then it leveled out and creeped up, and your water volume is much smaller.

since then, I really don’t even need to clean my glass. 
and I believe the amount of fish and feeding is keeping it balanced now.

 

cheers….

[oogie]

On 7/14/2024 at 4:00 AM, Staticmoves said:

I only had to dose PO4 for a few months, then it leveled out and creeped up

I think my tank has leveled out also.  I am also seeing phosphate creeping up.  How much did phosphate rise for you?

 

Thanks in advance! 

[Staticmoves]

59 minutes ago, oogie said:

I think my tank has leveled out also.  I am also seeing phosphate creeping up.  How much did phosphate rise for you?

 

Thanks in advance! 

I was maintaining .03-.04 by dosing. then on my regular test starting showing .07, so I immediately stopped dosing Po4 and monitored through testing. it went up to .09 then slowly came down to .05-.06 and there it have sat roughly.

same with my No3, it went as high as 25ppm, ( had some issues with ACRO's here.) now it has been steady around 5.0-7.0ppm.

[oogie]

2 hours ago, Staticmoves said:

I was maintaining .03-.04 by dosing. then on my regular test starting showing .07, so I immediately stopped dosing Po4 and monitored through testing. it went up to .09 then slowly came down to .05-.06 and there it have sat roughly.

same with my No3, it went as high as 25ppm, ( had some issues with ACRO's here.) now it has been steady around 5.0-7.0ppm.

Wow, very similar.....   I was maintaining 0.05 by dosing and today it showed 0.08.  So lets hope it will go up to about 0.1 then stabilize around 0.06 - 0.07.

[lwyatt82]

On 7/12/2024 at 10:19 AM, Staticmoves said:

around the 6 month mark I believe.

believe it or not, I have been having good luck with my dry rock this time around.

though I did change my method for seasoning from previous attempts. (Knocking on all kinds of wood.........🌲)

Could you please explain your new method? I currently have 40 lbs of marco rocks in a brute with rodi water. My plan is to check phosphate every week and replace water for about four weeks or so until phosphate isn't detectable. Am I on the right path? 

[oogie]

2 hours ago, lwyatt82 said:

Could you please explain your new method? I currently have 40 lbs of marco rocks in a brute with rodi water. My plan is to check phosphate every week and replace water for about four weeks or so until phosphate isn't detectable. Am I on the right path? 

Hi there, 

Back when we used live rock, we did often pre-cure rock in a brute container to start cycling so we dont have to deal with nasty die-offs. But as i learned after using marco rock, it absorbs phosphate instead of leeching it.  As having 0 phosphate is really bad for the tank, i think you will have to dose phosphate until rocks reach equilibrium and stops absorbing phosphates if you are using brand new marco rock.  If its from old tank, then I would assume you are on the right track.

[mcarroll]

On 9/18/2024 at 12:25 AM, lwyatt82 said:

Could you please explain your new method? I currently have 40 lbs of marco rocks in a brute with rodi water. My plan is to check phosphate every week and replace water for about four weeks or so until phosphate isn't detectable. Am I on the right path? 

Agreed with oogie...

 

Although just to point out the chemistry is more or less the same (for our purposes) between the major forms of limestone (calcium rock): calcite, aragonite, dolomite, etc.  All will bind phosphate pretty well....but only up to the concentration of the water it's in, and maybe in reality only up to 70% of that.  And the sorption rate is HIGH, so waiting weeks is silly.....chemically it'll be done in minutes.

 

More importantly in your case, for mined limestone that's been weathered by rain (consider as RO water), there's going to be no PO4 to speak of.  (Nor any other soluble nutrient.)

 

If your rock is "used" from another reef tank, it might have seen phosphate concentrations as high as 1.0 or 2.0 ppm, but more than that is quite uncommon.  (And in reality, a number <<1.0 is much more likely.)

 

Putting "1.0" or "2.0" rock into your new tank won't be able to re-create that concentration in your tank though, thank to dilution in your clean water....and 1 or 2 ppm isn't going to hurt any kind of reef creature either.  The worst some excess phosphate would do is grow a lot of algae if you carelessly light up all that rock without taking any care in the process NOT to grow algae.  But it wouldn't do that for long, begause that 2.0 ppm **was it** for phosphates.  Done.

 

You'll be adding FAR FAR more ppm of phosphate (and every other nutrient available) with every fish feeding, once the fish are in the tank.

 

So, it's good to be aware of phosphates, but also good to keep things in perspective.  Nothing to actually worry about....barely actionable....can be considered a benefit if you adjust your startup just a little.  🙂 👍

[Staticmoves]

@oogie thread here, what a great conversation.

And would be a great read for anyone new to newish dealing with "Dry Rock".

and it didn't take 20 pages of scrolling to get there.