Cannot get detectable nutrients

[Mandarin the first]

I’ve done a bunch of reading on the topic of undetectable nutrients but I am still confused about where to go from here as there are so many opinions. My tank has been running for about a year and is a lower stocked mixed reef with Zoas, hammer and torch corals doing well. I have a couple of small acro frags and colonies that are getting STN and going pale. The tank and sump is about 200L and was started with dry rock and dry sand. I dose to keep parameters stable:
Ammonia and nitrites 0
Salinity 1.026
Nitrates 0 (Red Sea pro)
Phosphate 0 (Hanna ulr)
Alk 8dkh
Calcium 420
Mag 1320
10% water change every week or two.
Only filtration is a skimmer. I have some cyano and a lot of hair algae. Is it my dry rock that is binding all nutrients? Should I dose no3 and po4? I have been feeding heavier with no detectable rise.

 

[Deezill]

If I were getting 0 phosphate and 0 nitrate I would stop all water changes. Before the dinos roll in
I would get some nutrients in the tank. start dosing phosphate and nitrate.

 

[Ky_acc]

No don’t dose anything - you have high nitrients that are being sucked up by the hair algae. Any nutrients you dose will just fuel the hair algae problem.

You should cut back on feeding - I recommend feeding pellets for awhile as those are easy to watch and make sure it’s all eaten.

I’d work on getting that hair algae under control do a large water change now and try and do a month or two of weekly 15-20% maintenance changes. Then start with manual removal of the hair algae to the extent possible. You could also introduce a few Mexican turbo snails to help which have always done a number on hair algae for me (I’d keep it to 1 turbo per 25 gallons or so)

That’s what I’d do

 

[Pod_01]

lot of hair algae.

As mentioned this is your top consumer, you need to trim it/ remove etc..

 

[Randy Holmes-Farley]

Can you post a picture of what you mean by a lot of hair algae?

I would give a different opinion and I'd raise nutrients by dosing N and P or feeding more. Regardless of the reason for N and P being low, pale corals may be from low N and/or P.

 

[Deezill]

Can you post a picture of what you mean by a lot of hair algae?

I would give a different opinion and I'd raise nutrients by dosing N and P or feeding more. Regardless of the reason for N and P being low, pale corals may be from low N and/or P.

Agreed.

 

[Pod_01]

As Randy mentioned pictures of the tank, algae and the acros that are suffering would help. Also pictures of the corals doing well zoa, torches would help.
Also what is dosed into the tank?

Should I dose no3 and po4? I have been feeding heavier with no detectable rise.

To me that indicates the algae is consuming the NO3/PO4. I have Reefer250 so when I had GHA outbreak I took out the stones and scrub them clean. Repeated the process few times and afterwards the NO3/PO4 increased.

I suspect part of your problem is here:

My tank has been running for about a year and is a lower stocked mixed reef

From my experience you either get the corals to cover the stones /exposed surfaces or algae will do it. These two compete for space and in general require same elements / environment to thrive.

I replaced some of my GHA with GSP. Nicer to look at, invasive but it prevents algae from growing.

It grows on its own rock and it is green…

Duncan corals are also nice and fast growers:

Chalice corals can also cover surfaces:

Faster growing zoas:

As the tank matures you can replace these with slower growing corals that you want.


Obviously things are growing in your tank, you just need to encourage the right things to grow. Re-Ballance and increase the coral mass.

Good luck,

 

[Mandarin the first]

Thanks everyone for the advice! I’m posting some pictures of the algae and some healthier corals aswell as the pale ones.

 

[Randy Holmes-Farley]

Thanks everyone for the advice! I’m posting some pictures of the algae and some healthier corals aswell as the pale ones.

The nutrients are likely not low enough to be a problem for corals in that tank, but it may be worth experimenting, at least temporarily, with dosing N and P or feeding more, and seeing if anything changes in the coral appearance. Ammonium chloride or ammonia carbonate would be a good way to dose N here.

 

[Pod_01]

I would remove as much of the algae as possible (manual). Scrub (tooth brush), pull also if the back wall/glass is covered clean it up.

PO4 can bind and unbind from the dry rock, so extra feeding can help. Since you have zero it is combination of the rock and algae.

NO3 is in the water, it doesn’t bind to rock. Most likely algae is consuming what is available. Adding snails can help, they are ammonia factory.

More fish as well can help with both PO4 and NO3. Also fish poop is good food for corals. How many fish in the tank?

As Randy mentioned you can try the liquid form of NO3/PO4. Sparingly or it can feed the algae.

What are you dosing?

I dose to keep parameters stable:

So I will propose something controversial. I would do some carbon dosing with Tropic Marin NP Bacto Ballance. Carbon dose to feed the bacteria 0.3ml a day for your tank. Start at 0.1ml and increase each week to 0.3ml. The idea being that the corals will consume the bacteria (food). You could use TM Plus NP but again low dose 0.3ml max.
Since you have few corals your dose might be 0.1 ml. If undesirable things pop up, back off to 1/2 the dose.

The corals that STN will need to be removed. Otherwise they rot and just pollute the water and algae will grow on them. You can snip the good portion and re-glue to a new plug. Or snip the infected part away.

Also flow might help so dead zones that promote algae don’t develop.

Out of curiosity, the SPS colony did you buy them or you grew them from a frag?

Good luck,