Phosban during cycle? Anybody want to be Mikey?

[Sk8r]

Reading Bertoni's comment that phosphate comes in on/via live rock---it does make sense, because it sure fuels one heck of an algae bloom at the end of the cycle.

Which suggests---maybe our traditional setup method, in which we let this go on, then fatten a batch of CUC on the resulting algae, is not the best way we could go. Phosphate IN algae can't readily be measured: but we know it's there, because there's algae.

What if---we ran Phosban during the cycle? No algae bloom?
We'd have to feed the CUC to prevent them starving during the last phase. But if the phosphate is floating around in the water ready to cause an algae bloom, and we yank it, via Phosban or a fuge, we have gotten rid of something our tanks don't want.

We still need a CUC: they're the turtle on which the universe rests, and imho they aid nitrate breakdown by their activity; but if we've sopped up the phosphate, corals would be happier faster. We might need a different kind of CUC, fewer snails, more worms, brittle stars, hermits, etc.

Opinions? I have a related thought on phosphate management, but I'll put that in another more specific thread.

[LockeOak]

I am inclined to agree. The nitrate and phosphate pulse in the last phase of cycling is pretty massive, hopefully larger than the tank will ever experience again. Does this scenario seem plausible? Algae types that were very rare on the incoming rock will explode in population, (hopefully) get knocked back by the CUC and later nitrate/phosphate reduction, but never go back to as low a level as they were when they were introduced. The result is small stubborn populations of algae and a starving CUC.

[Mike O'Brien]

The GFO only removes the P that's in the water. The algae that's growing on the liverock can get it there. There are many cases where there is very little P in the water, yet the algae continues to grow well. Consider a tank full of hair algae, or one with a thriving refugium, very often they have undetectable nutrient levels. Same with a real reef, the water is barren of nutrients, yet life thrives. If it were not for all the grazers, the reef would be overwhelmed with algae.

IMO algae are greatly responsible for the initial cycle in an aquarium.

[Sk8r]

In other words, interesting thought, you're saying the algae that grows first is actively extracting the phosphate from the rock, and that it would just sit there in the rock ready to cause problems if not FOR the algae?

[Mike O'Brien]

IMO the P in the rocks is not just sitting there ready to cause problems. That is bound to the rock. It's the very nature of the rock to contain P. It was live once after all. Bacteria and the algae's rhizomes can liberate it for their use.

Alo IMO it's not the P contained within the rock that causes the algae bloom in a new tank. Rather the nutrients from die off. Not only what was on the rock when it was put in, but also the bacterial bloom that happens. Usually there is an overpopulation of bacteria, some die as the the population has to reach equalibrium with the nutrients.

[Sk8r]

Interesting. So---counting that---the time to start phosphate-grabbing would be when the CUC starts to work and starts poo'ing it into the sandbed/water column.

[Mike O'Brien]

I guess it would be as simple as testing for P from the start of a new tank. It would be interesting to see what would happen in a test with two tanks. That would tell us if the GFO is faster than the algae and other life in the tank at grabbing up the P.

[Sk8r]

Good test, I think. If [I hope not!] I have to do a re-set-up on my current tank I will try running phosphate tests and at least see what the reading is. If it's leaching into the water it ought to show.

[3.99AfterTaxes]

What's a CUC?

[Sk8r]

CUC is a clean up crew...it's not a term I like to use in the newbie forum, for a very odd reason. Cukes, or sea cucumbers, are sometimes marketed as part of a CUC package---and imho, they are too dangerous for a new tank [as I think any large fleshy invert is a risk.] But some cukes are dangerous even to huge well-established tanks---as in cuke nuke, in which certain species, dying, toxify the entire tank. So I'll use it in expert areas quite happily, but I sure don't want a new reefer to run out there and try cucumbers because he's been orally told the term CUC and thinks cucumbers is the ideal thing to get.

The cleanup crew we mean is the normal complement of [1 animal per gallon] snails, micro-hermits, bristleworms, fighting conch, and sometimes, as above, more exotic types. All but the bristleworm [a slime specialist] eat algaes and poo the remnant into sandbed and water column. Algae contains many nutrients, among them, phosphate, that we want out of the tank. So this would be a time at which [as algae is eaten off the rocks and released] that a phosphate uptake medium like Phosban and Phosgard; or a refugium [with macro algae competing with the tank for nutrients 24/7] can grab the loose phosphate and get it out of the water system.

[Mike O'Brien]

I personally don't mind all the waste from the micro fauna. I probably have more particulates in my water than most. I have the filter feedes to show for it. Polycheate worms must number in the tens of thousands in my tank. IMO the waste they produce is food for my corals. Key being enough flow to keep the stuff floating around for things to eat. Skimmer included.

This is bringing up the difference between inorganic P and organic P. One being harmful to organisms we keep and the other being helpful.

[Sk8r]

Point, definitely: I've even maintained some [not all] sps with good extension with a lot of particulate---where it's produced by a lively ecosystem. Bali slimer, acropora valida, montiporas, all were very tolerant of this condition.

[m2434]

I have actually been playing with this a bit. On my 20g, I ran the GFO from day 1. The issue I 've noticed is that, if I stop running GFO, the algae appears in force with a day or so.

My assumption was that the P did not increase that dramatically, all of a sudden when the GFO was removed. Instead, I believe, some micro-algae may demand more N and Fe than P. In this case, when running GFO, the N and Fe rise slightly, because P is limited and N and Fe are therefore not as readily consumed. Because, these algae do not require much P, the slight increase is sufficient for them to utilize the now increased N and Fe. (Note inorganic N was not detectable on a test kit, but I'm not using anything particularly accurate such as a photometer, I don't test for Fe and there could be another nutrient I'm not accounting for – I'm not implying N and Fe are the only limiting nutrients, they are just examples)

My thought was that maybe it's more beneficial to allow nutrients export in a more balanced ratio. So, a few weeks ago, I removed the GFO and did not replace it. It took a while, but the algae has essentially disappeared. So, other organisms and my cheato have likely taken over. So, I think my theory could be correct, but there are thousands of other possibilities (Of course leaching of phosphates from the rocks is another) and I'm curious to hear what others think. Is the algae occurrence due to an unbalanced nutrient ratio? Is it better to rely on other means of export such as cheato from day 1?

This is an interesting topic, I'm glad someone brought it up. Also, if there is a nutrient balance issue, I think this also ties into the question of how often and for what duration, should GFO be run under normal circumstances?

[Mike O'Brien]

What I like about using algae instead is that exactly. It's never going to get any one nutrient too low for the corals. I do add Fe for the algae only.

I do believe that different algae prefer different nutrient ratios. Cyano being one that can provide it's own N, thrives in low N conditions.

[m2434]

Originally posted by Mike O'Brien
What I like about using algae instead is that exactly. It's never going to get any one nutrient too low for the corals. I do add Fe for the algae only.

I do believe that different algae prefer different nutrient ratios. Cyano being one that can provide it's own N, thrives in low N conditions.

Nasty stuff! Cyano can also utilize insoluable forms of Fe theought the use of siderophores.

[Big E]

If I was going to do this, I'd run the GFO & keep the rock in the dark.(rock cooking) Any Po4 that's leaving the rock will go into the water column for the GFO to absorb & there won't be any algae there to nab it. You won't need a CUC during this stage either.

Other than pods & such I could care less about the rock life. Most of it is pest algae & every tank I ever owned over the years, the corals end up completely covering or shade the rock surface.