Where's my PO4? and how would carbon dosing help?

[IPT]

Briefly I have a 120 GAL mixed reef that is not particularly heavily loaded. it's a crashed tank i am resurrecting. I have have had 0 NO3 and PO4 and have been dosing Brightwells products. I have the Nitrates up to 5, but the Po4 is still zero. using Hanna testing for both. I poured some PO4 additive into the test tube and it did change color so I think it is working properly. On the Brightwell stuff it says if the PO4 doesn't come up you are carbon limited. I thought carbon dosing was done to bring PO4 and N03 DOWN.


I have dosed a lot of the brightwell product and I have a lot more algae (even lots of bubbles coming off of it), and better color in my Miyagi Tort, but everything else looks the same or worse. Something is amiss.

PH is between 8.1 and 8.2, Salinity 35ppm, Alk (Hanna tester) 9.1-9.3, Ca 460. Oddly my Mg just tested way high, like 1500 after being low and my dosing.

Thoughts? Explanation as too why carbon dosing would help an inability to bring up P04 levels? I thought carbon dosing increased bacteria and brought it down (incidentally my water is for sure not as crystal clear as it once was).

 

[blaxsun]

Carbon dosing will lower your nitrates and phosphates - which is the exact opposite of what you're trying to achieve. I'd continue dosing phosphates and testing; you won't see overnight results, but stick with it (nitrates are already moving in the right direction).

 

[IPT]

Carbon dosing will lower your nitrates and phosphates - which is the exact opposite of what you're trying to achieve. I'd continue dosing phosphates and testing; you won't see overnight results, but stick with it (nitrates are already moving in the right direction).

Thats what I thought which is why the instructions from the bottle confuse me:

"Allow 24-hours to elapse; re-test nitrate and phosphate concentrations. If concentrations remain unchanged, then the system is likely carbon-limited. Dose with REEF BIOFUEL at the rate of 1-ml per 25 US-gallons and allow 24-hours to elapse, then re-test phosphate and nitrate concentrations. Continue daily dosing with REEF BIOFUEL until phosphate or nitrate concentrations begin to decrease, indicating that the rate of carbon input to the system
matches the rate of phosphorus- or nitrogen-input, respectively."

Seems to me they are saying if I am adding the Neo-Phos level should be going up and if they are not it's because my system is Carbon limited.

Also I have does a TON more then they recommend so far (over about 2 weeks) to see no change. I still test 0 for P04, but honestly aside from the Miyagi, my tank looks worse. Something is askew and I guess I don't understand the potential missing link.

 

[blaxsun]

What are you using for a testing kit?

 

[IPT]

What are you using for a testing kit?

Hanna colorimeters for (low) P04, N03, and Alk. RedSea (and sometimes I'll double check with an Aquaforest) for MG.

 

[Randy Holmes-Farley Verified Community Expert]

Briefly I have a 120 GAL mixed reef that is not particularly heavily loaded. it's a crashed tank i am resurrecting. I have have had 0 NO3 and PO4 and have been dosing Brightwells products. I have the Nitrates up to 5, but the Po4 is still zero. using Hanna testing for both. I poured some PO4 additive into the test tube and it did change color so I think it is working properly. On the Brightwell stuff it says if the PO4 doesn't come up you are carbon limited. I thought carbon dosing was done to bring PO4 and N03 DOWN.


I have dosed a lot of the brightwell product and I have a lot more algae (even lots of bubbles coming off of it), and better color in my Miyagi Tort, but everything else looks the same or worse. Something is amiss.

PH is between 8.1 and 8.2, Salinity 35ppm, Alk (Hanna tester) 9.1-9.3, Ca 460. Oddly my Mg just tested way high, like 1500 after being low and my dosing.

Thoughts? Explanation as too why carbon dosing would help an inability to bring up P04 levels? I thought carbon dosing increased bacteria and brought it down (incidentally my water is for sure not as crystal clear as it once was).

Ignore that carbon limited comment from Brightwell. They do not have a good understanding of chemistry.

Most reef tanks are carbon limited, and they should be. All that means is that if you add organic carbon (such as vodka, vinegar or sugar), bacteria will grow in it.

 

[IPT]

Ignore that carbon limited comment from Brightwell. They do not have a good understanding of chemistry.

Most reef tanks are carbon limited, and they should be. All that means is that if you add organic carbon (such as vodka, vinegar or sugar), bacteria will grow in it.

Thanks Randy. What confuses me is that they say adding Carbon will help if your levels are NOT rising. I thought Carbon dosing was used to bring P04 and N03 down.

I'll also still baffled at how I added like 250mls of the stuff and still have zero P04.....

 

[Randy Holmes-Farley Verified Community Expert]

Thanks Randy. What confuses me is that they say adding Carbon will help if your levels are NOT rising. I thought Carbon dosing was used to bring P04 and N03 down.

I'll also still baffled at how I added like 250mls of the stuff and still have zero P04.....

That's why I say ignore them. Brightwell has a number of challenges understanding chemistry of their own products.

Brightwell's products are also quite dilute and lack any purity guarantee. Look for a DIY.