Cant fight algae in dt

[kotlec]

Just rechecked to be sure :

No3 - 1.5 Salifert (good for SPS)
Po4 - 0.00 Hanna (deadly for SPS)

[Floyd R Turbo]

This "P coming from rocks" is just a guess that fits the situation nicely. There is no hard science or definitive proof either way (proving or disproving) the "P leeching" concept. So let's set that straight first.

For chemically deposited phosphate, which precipitates out of the water at pH above 8.0 and best at 8.4, this P is chemically bonded and not dissolved just because the P in the water is brought down (let's be clear, this is not a chemical possibility), you would have to lower pH to 7.0 or less for this P to dissolve back out, chemically speaking. The other possibility is that there is some kind of symbiosis between bacteria and algae that is creating a localized low pH at the rock surface that creates the ability to access this bound P, but in the process of releasing the P this raises the pH locally, so this would have to be a rather slow mechanism, if it even exists.

For "sludge" deposits, or top-layer detritus, etc, this is likely more soluble and can become a source of nutrients for algae, but should be short lived if you had a large algal outbreak.

What is more likely is that your P is coming from the food you feed, as P is in the cells of almost everything, and when the food is processed/digested, this P is released into the water. Your rocks will adsorb this P through the previously mentioned precipitation in a high pH environment, until the rocks become saturated and this process slows, resulting in a slow rise of P in the water column that is available for algal uptake. This may be what you are seeing - your scrubber is able to uptake much of the P, but not all of it.

Again, that is just a theory that could potentially explain what is going on, but there's so little research into this and each tank is so specific, there could be multiple explanations. It could just be a temporary cycle, it could be a bacterial colony crash (and the effects you are seeing would be much worse if you didn't have a scrubber), etc.

Have you changed anything at all? lighting? Food? Livestock? Rearrange tank? Add rock? Remove rock? anything?

[kotlec]

I did not move even a piece of sand in tank when all this happened. The worst thing what comes to my head is that my son during my wacation could forget to feed fish several days and then dump 2 or 3 day dose in a hit. But that is also not likely.

Folowing the idea of saturated rock one thing comes to my head is that i never had phosphates higher than 0.04. OK you will say that was a result of rocks absorbing P, but why then now, when rocks are saturated and not absorbing anymore , my P is still at 0.00 ? It should have rocketed since reached saturation point.
Another important factor is that I keep my tank semi starved as my corals didnt have nice colors. I believed that reason was phosphates. But now I thing that it is more likely lack of phosphates and not excess.

Bacteria colony crash looks most realistic to me. I do not understand this mechanisms at all , but it sounds to me very trustworthy.
Bacteria or any other micro life inside rocks crash and initiates algae to grow on its leftovers. I believe this even can replace " P leaching from rocks " theory.

[SantaMonica]

Because their P is already out of the rocks.

Screen pics would help, but I'm pretty sure even without them.

[Floyd R Turbo]

Low P has nothing to do with flow of P from rocks to scrubber. You could have a river of P flowing.

Because their P is already out of the rocks.

I am totally confused.

[kotlec]

Screen growth very well coresponds P measurings.

P= 0.04 screen grow nicely
P= 0.02 screen grow somehow
P= 0.00 screen grows alien algae, or stops growing at all. (Today's situation)

Never had higher P to extend this list.

[Mason Dixon]

I've got the same problem with a DT covered in algae, but my ATS is growing it great as well. I'm thinking the flow from my return pump is not cycling the water through the DT fast enough and, as a result, the fish waste is becoming algae food before it can get to my skimmer/ATS. I will be upgrading pumps this next week(300gph to a 1000gph in a 135g tank).

[SantaMonica]

Flow has nothing to do with it. If your scrubber is growing good, then it's working well.

[Floyd R Turbo]

I completely disagree given the facts. He has a 135 with 300 GPH through the filtration. Even without a scrubber, his filtration system is on a crutch due to this.

[cdm2012]

I came across this article entitled: "Nitrate (NO3) and phosphate (PO4) don’t cause algae. Ammonia does!!"

Here are some quotes:

There is this myth, that nitrate (NO3) and phosphate (PO4) cause algae which is spread like a wildfire...algae lives in two stages. First stage is an algae spore and second one is common algae...Algae spores are invisible and they are present in each aquarium... they need for their growth ammonia (NH4) and energy – light...algae spores want ammonia (NH4)...Ammonia comes from...waste of fish and from feed...

and I'm sure any dead, decaying thing in the aquarium will produce ammonia. Including dead bacteria.

And of course the article then tells us what we already know about algae:

...algae eats nitrate (NO3) and phosphate (PO4)...

Could this be what is leeching out of live rock? Perhaps, dead creatures, including bacteria, inside the live rock is slowing decaying and causing a ammonia to slowly leak out. This would give food to the ever present algae spores causing it to produce algae and then the newly grown algae consumes the surrounding nitrate and phosphate in the water. And I'm sure this phenomenon would continue until the decaying process ends.

Could it perhaps be ammonia causing the problem?!?