No algae with high nutrients and 6500k lighting...

[Harrisonjc8]

So I started this 29g tank as a experimental tank to see all the effects of growing coral under different spectrums of light. Currently it has been running a 6500k led for around 2months with coral. It has been setup up as a Fowlr for around 6 months prior to that. I never was concerned about testing because I've never had any major problems with the tank. The only major things I've had happen where a slight gha outbreak for a week, diatoms(before I started to used rodi), and a algae bloom( lasted about a week as well). Other than that everything has been going smoothly but I got interested in what my parameters where so I went out and bought a cheap api reef master test kit. I know they can be hard to read but I only wanted a general idea of my water parameters so I did not really care. But to my surprise, according to the api test kit my Nitrates are around 15-20ppm. Phosphate is around .5 to 1.0ppm. DKH is 12 and calcium is around 400ppm.

So the part that I need a second opinion on is why I don't have major algae problems. I barely have any algae, and I usually just get a light bio film on the glass every day. Everything is growing great and I have had no issues. But I thought for sure with the combination of 6500k light and high phosphate I would have major algae problems but I don't? Does anyone know why that could be? I'm not complaining, I'm just interested as to why. I don't run a refugium, skimmer, cheato reactor, or any chemical media. Just filter floss and bio balls. So what is preventing algae growth( not that I want it)?

Also I only have 2 fish. Which are a clownfish and a goby. The reason my nutrients are so high is because I just like to feed alot to my fish and coral. Oh and for coral I have:

2 differnt types of Birdsnest. One is a thin branching and the other has thick branches.
A encrusting red monti and a plating red monti.
A branching monti with yellow polyps.
2 types of gsp.
Pulsing xenia
porites
eagle eye zoa
Favia or goniastrea( can't really tell)
and another coral which I can't identify cause it was dying when I got it and it's still slowly recovering.
( I don't really know the exact names of all the corals so forgive me,, but they were all $5 frags from wwc so I didn't really bother asking lol)
Nothing has died, bleached, stn, or rtn, and it's all growing. Which is why I haven't bother testing.

The light is 2 6500k led flood lights from lowes (1000 lumens). Also recently I added 2 t8 bulbs as well. A actinic bulb and a black light. ( these are just to see how they affect coral growth and color, cause this is an experiment tank with $5 frags). And the tank is a aio 29g I built myself.

So any opinions on this would be great. Thanks in advance.

 

[blaxsun]

Any fish or inverts?

 

[Harrisonjc8]

A clown, goby, 6 blue leg hermits.

 

[Spare time]

I don't trust API phosphate test. It is arguably the worst phosphate test in the hobby

 

[Dkmoo]

no3/po4 levels is not the primary cause of algae growth. They grow when there are spots that allows it to grow. Think in the ocean no3/po4 levels are nearly undetectable, yet algae still grows in areas with dead organic matter and/or unbalanced ecosystem.

I'm guessing that your rocks are already fairly mature from the FOWLR days and are "live" with coralline and other living micro critters? this effectively limits the available real estate that algae can get a foothold, thus limiting its growth. This is also why your glasses gets a film every day - it's one of the few spots that has that "prime real estate".

Algaes also prefer ammonia more than no3. it's possible that your tank already has a very strong competition for ammonia between your bacteria, coral zoox, and the film algae on the glass, that it further slows down other algaes from taking hold if all it has to go on is the NO3, which it can use but will be harder/takes longer - it's also only been 2 months.

 

[Heisenberg 78]

I think this may be down to bacteria, I ran my reefer 350 for months with no3 at 50-70ppm and po4 at 0.5 ish.
..on paper you would expect severe algae outbreak: but this wasn’t the case.

I had cheato in the sump with mangroves which barely grew, and I had some of the nicest lps and Zoas growing like crazy.

I moved away from this chemistry a few months later, I removed the cheato and started tackling nutrients in order to lower them for sps.
I noticed after a few weeks the shift in my movements caused algae to finally break through
Ive recently gone through a gha stage in my sump along with a cyano/ (Dino maybe)and a brown looking turf algae in the tank.. (not bad but visible)
Im only just getting it to disappear, but my nutrients are only just starting to get them where I want them.. 4 ppm no3 and 0.04po4

I think the bacteria biomass in the tank was limiting the algae and preventing it taking hold..and it was through altering the dynamics of the available nitrogen that the algae came out of hiding..