Keeping algae out of a marine aquarium

[LordJoshaeus]

Hi everyone! Forgive me if this is an unusually long version of this question...anyhow, I once thought that keeping algae out of any aquarium - fresh or salt - required keeping nutrient levels as close to zero as possible so the plants/macroalgae/corals would take all the nutrients and starve the algae out; even when I did this, though, I had heaps of algae problems in both fresh and saltwater (dinoflagellates in the latter). More recently, I discovered that this is not the way to do it with freshwater tanks; I learned that algae in freshwater tanks is caused by;
- Ammonia (dum dum dah!!! Nitrate or phosphate excesses don't directly cause algae in freshwater aquariums, though they can hasten its spread if something else goes wrong. Ammonia is inevitably a problem).
- Fluctuating/low CO2 levels (the latter only if the plant is not getting as much CO2 as it needs)
- Excess detritus (including decaying aquarium plant leaves...unhealthy plants are algae magnets). The sugars and similar compounds these produce encourage algae to settle and grow on these surfaces, even in tanks with low nitrate/phosphate.
- Poor circulation
- Nutrients are too low (a common cyano trigger is nitrate levels being too low for some of the plants).

By applying these, I am doing markedly better in controlling algae in my planted freshwater tanks. My question is, how much of the above is applicable to saltwater tanks? I suspect that CO2 isn't a major issue (though I wonder if macroalgae/seagrasses would do better if I increased CO2 levels by a few ppm? Increasing it more than that would likely lead to PH issues). Thanks

 

[Lasse]

NH3/NH4 and amino acids is the most cost effective nitrogen sources for single cells organisms to use. Many of them also lack the enzymes needed for convert the NO3 into NH3/NH4 necessary for transport in the cell. Higher plants and most macro algae have normally these enzymes and can use NO3 as an N source. In this way - your experiences is valid and probably right. To minimize the NH3/NH4 (with good nitrification) in a freshwater planted tank in order to minimize the algae problem may work.

In saltwater - it seems to be a little more complicated - because if it is corals we want to have - their zoox indeed are single cells algae - dino-flagellates. Even if it looks like there is pathways for NO3 as N source even for corals - the NH3/NH4 - N is more cost-effective way of getting inorganic N for the photosynthetic process. Many reefers experiment with NH4Cl as primary adding source in nitrogen limited aquarium

In the beginning of reefing - good biological nitrification was one of the goals. After years of preaching about biofilter as nitrite factories - many reefer avoid them as if they were infected with the plague. It interesting that @AquaBiomics have indicate that nitrification bacteria is more common in the water of very successful aquarium compared with many not doing as well as these. Let me say - there have always been good nitrification filters in my salt water aquariums.

Sincerely Lasse

 

[LordJoshaeus]

Well, I guess I'm at least partially right...that counts for something, right? ;Wacky Could corals be provided with the needed nitrogen levels simply by target feeding them a couple times a week, or would the ammonia they produce as waste be released into the water column like other animals and then get oxidized to nitrate? In the absence of corals, could I run a macroalgae tank on the above principles?

 

[Lasse]

could I run a macroalgae tank on the above principles?

For sure - but there is testing according dose NH4Cl direct into macro algae tanks too - see here

Build Thread - Nano Macroalgea Tank

Hey guys! Though I'd share my Macroalgea tank. Since I'm fascinated about them they are the main focus of the tank. I am still learning since it's my first saltwater tank and it's just a couple of months old but I want to show how it progresses.

www.reef2reef.com

Could corals be provided with the needed nitrogen levels simply by target feeding them a couple times a week, or would the ammonia they produce as waste be released into the water column like other animals and then get oxidized to nitrate?

Thats the $ 1 000 000 question. Probably will the zoox take up animal produced NH3/NH4 (and amino acids) direct from the corals body fluids

Sincerely Lasse