Aglae ID, Just Part Of The Ugly Phase?

MarshallB · Nov 24, 2020

Salinity 1.026
Nitrate 0
Phosphate bounces from 0 to < .02
PH 8.2
Alk 10
Calcium 440
Mag 1500
I use RODI water, 0 TDS.
Tank Age: 6 Months.

So this stuff has been in my substrate for awhile now, it was brown, but now is green. Substrate gets plenty of flow. I've had to adjust it a few times to keep it from blowing around. Grains of the substrate move now and then with the flow if I watch.

At first I assumed it was Diatoms. I don't have a microscope to confirm. Do they turn green like this? It is not easily cleanable and does not come off when I vacuum it. In fact it causes the substrate to clump up in the areas it is attached to. Lately, I've been going in and just stirring it up a long with weekly vacuuming. I've tried removing some of the substrate to clean it, but this stuff does not float in the water and just mixes in with the substrate. It's almost as if it is stained on the substrate.

I just want to make sure this is something I should wait out, and not need to take any immediate action on it. It is definitely much much lighter in the mornings and brightens up after a few hours of the lights being on.

Most corals are doing very well, and coraline is taking off at a pretty good pace now. I do have a few different types of Zoa in the tank and they have not fully opened in about a month now. Previously they were fully extending. The CUC and tangs seem to keep them pretty clean. I do not see any algae growth on them or on their bases. No spots and it doesn't look like anything is eating them. It could be from lack of nutrients, but they should be getting plenty. I use DIY food that includes a little bit of reef roids and other fine particle foods along with bigger stuff for the fish. Only reason I bring this up is the two could be related, or it could just be a coincidence.

Thanks!

schuby · Nov 24, 2020

You list zero nitrate and zero phosphate. I see that you have at least two fish. What do you do to remove nitrate and phosphate from your system?

MarshallB · Nov 24, 2020

schuby said:
You list zero nitrate and zero phosphate. I see that you have at least two fish. What do you do to remove nitrate and phosphate from your system?

A refugium and a skimmer.

Edit: to add to that, the refugium has only done a great job of growing hair algae so far. The chaeto just kinda stays the same. I have some Ulva on order to see if it will grow any better.

schuby · Nov 24, 2020

Hard and soft corals don't like zero phosphate or zero nitrate. They'll usually end up dead. If you have macro-algae in your refugium, consider reducing the light-period and reducing the amount of macro-algae. You may also think about feeding your fish more. Do you feed your tang seaweed/nori? I'd leave the skimmer on.

Myself, I target phosphate of 0.1 to 0.2 ppm and nitrate of 10-20 ppm. Having zero of either tends to put your tank into a bad place.

The green in your sand looks like a normal part of the ugly phase to me. Do you have a CUC? They help a lot with that kind of stuff.

MarshallB · Nov 24, 2020

schuby said:
Hard and soft corals don't like zero phosphate or zero nitrate. They'll usually end up dead. If you have macro-algae in your refugium, consider reducing the light-period and reducing the amount of macro-algae. You may also think about feeding your fish more. Do you feed your tang seaweed/nori? I'd leave the skimmer on.

Myself, I target phosphate of 0.1 to 0.2 ppm and nitrate of 10-20 ppm. Having zero of either tends to put your tank into a bad place.

The green in your sand looks like a normal part of the ugly phase to me. Do you have a CUC? They help a lot with that kind of stuff.

Yeah thats my struggle right now. I had the fuge on a opposite light schedule from the display, but I started testing phosphate over 1.0 so I turned the refug light on 24/7 which dropped my levels to 0. The Zoas were half opening before I turned it on to drop the levels. I do have a sizable clean up crew, but they do not touch whatever that is on the substrate. I have blue legged hermits, and a variety of snails.

Either way I cant seem to find that fine line of just enough nutrients.

I do feed Nori. It takes them about a day to go through a full sheet. I usually put a sheet in every 2-3 days.

I have not tried increasing feeding yet.

schuby · Nov 24, 2020

Was your sand green before you dropped your nitrate and phosphate to zero? Hope you are not using API for any testing.

I try to feed my tangs as much seaweed as they'll eat in a day. If there's anything left the next day, I dump it and put fresh in. I try not to put more in then they eat, but I'm not perfect.

Try to get your phosphate and nitrate levels up, then see how your sand does. It may clear up with more nutrients and more time.

MarshallB · Nov 24, 2020

The spots on the sand were brown before. They weren't nearly as noticeable before. I assumed it was diatoms. However, it did not come off easy either.