Correct NO3 + PO4 Dosing Ratio To Avoid Reducing Either to 0.0?

[Randy Holmes-Farley Verified Community Expert]

Thanks for the idea. I wanted to keep it low as I'm trying to avoid a major outbreak of pest algae, but maybe I can shift to targeting raising to 0.07 setpoint, and dose if it gets as low as 0.05. I can always adjust down a little if something pops up. Thank you!

Trying to reduce pest algae by keeping nutrients low is typically a fail if corals are present as thy need the same nutrients at similar levels.

 

[Miami Reef]

I like to dose 0.10ppm PO4 in one shot. The rocks will get saturated faster and it’ll be quicker to equilibrate. Plus, you don’t have to test often.

 

[naterealbig]

Trying to reduce pest algae by keeping nutrients low is typically a fail if corals are present as thy need the same nutrients at similar levels.

Thanks Randy, this makes sense, and I should know as I've read exactly this (probably in your posts) several times.

While you're here: am I completely sideways by also trying to avoid pest algaes by keeping the system fishless (assuming there are crabs and other inverts, and am feeding these regularly (pureed mix of reefroids, reef chili, aminos, clams, mussels, and oysters) ?

 

[naterealbig]

I like to dose 0.10ppm PO4 in one shot. The rocks will get saturated faster and it’ll be quicker to equilibrate. Plus, you don’t have to test often.

Thanks - what you are saying makes sense. I'll retest again tonight and if PO4 & NO3 is still moving at a snails pace, I'll up the dose.

 

[Miami Reef]

While you're here: am I completely sideways by also trying to avoid pest algaes by keeping the system fishless (assuming there are crabs and other inverts, and am feeding these regularly (pureed mix of reefroids, reef chili, aminos, clams, mussels, and oysters) ?

What type of algae are you dealing with?

 

[rtparty]

Herbivorous fish very early on is a great way to stay ahead of algae.

Algae is not a symptom of excess nutrients; it is a symptom from a lack of herbivores.

 

[rishma]

Algae is not a symptom of excess nutrients; it is a symptom from a lack of herbivores.

I just don’t follow this logic, though I see it stated a lot recently by knowledgable reefers like yourself. Maybe you can convince me.

Algae problems, in my experience, have always been coincident with excess nutrient supply. I have had examples when measured nutrients were low because heavy algae growth was using it quickly, but the nutrient supply was excessive.

To be clear, I have seen high nutrients without algae problems. I would not say those cases are primarily different due to herbivores. They tend to be very mature, coral dense systems.

I am fan of herbivores, but it seems like this sentiment that it’s not a nutrient issue leads people to a more difficult path of algae management.

 

[Miami Reef]

Algae problems, in my experience, have always been coincident with excess nutrient supply. I have had examples when measured nutrients were low because heavy algae growth was using it quickly, but the nutrient supply was excessive.

What’s the purpose of stripping the tank of 0 nutrients if there will almost always be a nutrient supply in our tanks?

If there truly is near 0 nutrient supply, dinos often take lead. Unfortunately, there aren’t any herbivores for them.

 

[Randy Holmes-Farley Verified Community Expert]

I just don’t follow this logic, though I see it stated a lot recently by knowledgable reefers like yourself. Maybe you can convince me.

Algae problems, in my experience, have always been coincident with excess nutrient supply. I have had examples when measured nutrients were low because heavy algae growth was using it quickly, but the nutrient supply was excessive.

To be clear, I have seen high nutrients without algae problems. I would not say those cases are primarily different due to herbivores. They tend to be very mature, coral dense systems.

I am fan of herbivores, but it seems like this sentiment that it’s not a nutrient issue leads people to a more difficult path of algae management.

What nutrient levels do you think minimizes algae while not limiting corals?

 

[Miami Reef]

Don’t get me wrong: I really like my tank when it has low inorganic nutrient readings. It’s my opinion and personal belief that my corals grow faster than way.

However, limiting algae growth is not one of the reasons I like my nutrients low. Algae grows well in both environments IME.

 

[rishma]

What’s the purpose of stripping the tank of 0 nutrients if there will almost always be a nutrient supply in our tanks?

If there truly is near 0 nutrient supply, dinos often take lead. Unfortunately, there aren’t any herbivores for them.

I definitely do not propose stripping nutrients near zero. In fact, I think targeting as low as ocean level nutrients is a recipe for disaster. Dinos are nightmare.

I can grow algae just as well as when I ran high nutrients.

My observation is different. I really think algae grows slower with lower nutrient levels. I think the worst algae nightmares have been coincident with very high nutrients. I’d still prefer that over dinos.

What nutrient levels do you think minimizes algae while not limiting corals?

I don’t know the answer. I target about 0.1 ppm phosphate and it seems to work well. In my current tank I previously had hair algae problems and 0.3 ppm phosphate and 20 ppm nitrate. My corals seemed fine. As I lowered phosphate, hair algae growth was slower. I now have very little hair algae and if I had herbivores I’d probably have zero.

I’ve had similar experience in prior tanks. I cannot give a number that is good or bad, but the trend lower nutrients helps mitigate algae. Really high nutrients often resulted in algae problems.

With regard to not limiting coral, I suppose it depends on what other sources of nutrition they are getting.

Again, I don’t know the right answer, but I feel like the current algae problems are not due to excess nutrients is not helpful.

 

[sixty_reefer]

What nutrient levels do you think minimizes algae while not limiting corals?

Could the answer be dependable on the ammonia level? The OP is doing an interesting experiment where he/she is cycling a new tank with just coral and no obvious source of ammonia, instead he’s using just nitrate and phosphate to give the corals some nutrients.
He’s plan is by not having a obvious ammonia input to minimise the algae growth in is system at least that’s my interpretation of his plan.

 

[Miami Reef]

Again, I don’t know the right answer, but I feel like the current algae problems are not due to excess nutrients is not helpful.

You’re right; Nutrients do play a role.

Algae need nutrients, flow, light, space, CO2, trace elements, and a lack of predators.

It’s most simple and proactive to find a herbivore targeted to the problem algae, and only that algae, rather than trying to balance the other factors that might limit coral growth and health.

Algae scrubbers work because they keep the algae away from herbivores. If not, what’s stopping them from also growing in the tank?

 

[rtparty]

Don’t get me wrong: I really like my tank when it has low inorganic nutrient readings. It’s my opinion and personal belief that my corals grow faster than way.

However, limiting algae growth is not one of the reasons I like my nutrients low. Algae grows well in both environments IME.

Absolutely.

There are many reasons to keep “clean” water but controlling algae growth isn’t one of them.

It’s like not fertilizing your grass to keep the weeds out. The weeds are still going to grow in the poor environment and your grass is going to suffer from lack of nutrients.

Richard Ross’ MACNA talk is one of my favorites on the topic

 

[Miami Reef]

It’s like not fertilizing your grass to keep the weeds out. The weeds are still going to grow in the poor environment and your grass is going to suffer from lack of nutrients.

That’s a brilliant analogy.

 

[naterealbig]

What type of algae are you dealing with?

None right now, but reset a tank with acros and starting with nothing but a small tray of sand sand. Just want to keep it that way :)

 

[naterealbig]

Herbivorous fish very early on is a great way to stay ahead of algae.

Algae is not a symptom of excess nutrients; it is a symptom from a lack of herbivores.

Well I'm trying to minimize ammonia sources to aid in keeping algae away, but I've got a small army of hermits acting as the herbivores.

 

[rishma]

Absolutely.

There are many reasons to keep “clean” water but controlling algae growth isn’t one of them.

It’s like not fertilizing your grass to keep the weeds out. The weeds are still going to grow in the poor environment and your grass is going to suffer from lack of nutrients.

Richard Ross’ MACNA talk is one of my favorites on the topic

ok, but are nitrate and phosphate the preferred nutrition for corals? Is the answer different for algae? Honest question.

I am wondering if I’m getting lost in some nuance here….There are many reasons to keep “clean” water but controlling algae growth isn’t one of them.

Do you agree controlling inorganic nutrients does help control algae? Is your argument that is just not worth doing it?

Taken another way, if someone has an algae problem and high nutrients, would you not support a recommendation to lower their nutrients to help with algae?

 

[rishma]

It’s like not fertilizing your grass to keep the weeds out. The weeds are still going to grow in the poor environment and your grass is going to suffer from lack of nutrients.

That’s a brilliant analogy.

It’s a clever analogy but I feel it’s misleading. I am not advocating starving anyone’s corals.

If your fertilizer preferentially grew your weeds faster than your grass, would you recommend using less fertilizer??

 

[naterealbig]

Could the answer be dependable on the ammonia level? The OP is doing an interesting experiment where he/she is cycling a new tank with just coral and no obvious source of ammonia, instead he’s using just nitrate and phosphate to give the corals some nutrients.
He’s plan is by not having a obvious ammonia input to minimise the algae growth in is system at least that’s my interpretation of his plan.

Yes, that's my intent almost perfectly stated. Although I don't have the resources to perform a true experiment, I wanted to log my process/progress/failure for anyone who may be interested.

I seems to me that with respect to new tanks, ammonia is what gives all the weird stuff that shows up in the ugly phase the upper hand, so I'd like to try to minimize it, or at least maintain a slow addition for the first few weeks/months. Along that line (and for my specific goal) I want to provide what the corals need nutrient/nutrition wise (through small real food additions and inorganic NO3/PO4) but not an excess, as there's really nothing to consume the extra right now except algae/cyano/dinos or whatever.

I actually got the idea from Roberto Denadai, who started a (beautiful) sps reef with unseeded plastic rocks and siporax. He added corals to this system almost immediately. When i asked him how he did it, he said "simple, i just didn't add any fish" (right away) and let the corals and frag plugs act as the bacteria 'source'.

Here was the system, but i can't find the original thread. May be on rc... I'll try to find, and will post.