What tds was the tap water, the algae has to be getting food from somewhere?
What are your nitrates and phosphates?
Not sure about the TDS, but I was testing nitrates and phosphates for the first few months. So while it was ramping up, before and algae, and then while the algae was growing. Registered 0.5 nitrates once, then 0. Always had 0 phosphates on the test. So obviously there were nutrients but being taken up.
As you say, it is getting food from somewhere. I would say that the likely causes are the fact that I like whiter light over bluer, and I feed too much.
No mystery there... But now what I'm looking to do is bring my system up to the point where it can handle those levels of nutrients I suppose. And manage through in the meantime.
I've cut back on the lighting, and boosted the fuge (more on that below). I'm reluctant to pull back on the feeding given how happy the fish, soft corals, and shrimp are.
Another point is that I am not getting terrible growth on the glass. Don't have to clean it that often, and when I do it comes off easily as opposed to the more tenacious growth in the fuge for example. It's a more "powdery" algae on the glass in the DT, as opposed to the GHA on the rock (and sand in parts).
Oh, another point is Coraline algae. Didn't have much. I do test alk, and through the fall it stayed up even without dosing. Makes sense as I only have one very small SPS frag. I dose Tropic Marine Biocalc which is a powder. My LFS recommended I keep up a dose, even if just a tiny amount daily. I've been doing that and am now starting to see more Coraline appearing and spreading.
Do you have a pic of the fuge please?
It could still be catching up down there, hopefully it should out compete the gha soon.
How much do you feed?
Yes, I'm sure that is part of it. Until about six weeks ago I just had a 20w led grow light on the fuge:
That small bunch of chaeto was about the same size that it had been since I'd got it. But the GHA was doing we down there too.
Before Christmas I got a 300w MarsHydro. Excuse the mess, but it is what it is:
I pulled out a mess of GHA from the fuge when I cleaned the display at the start of Jan. But you can see that the chaeto has also taken off. It went from around 6" across to around 18". So a big jump in terms of volume.
That corresponds with the slowdown in the speed of GHA growth in the tank. But it also corresponds with the reduced whites up top as well, and the GHA is definitely still growing up top.
The light on the DT is just one Marine Orbit. Which is only 90w or thereabouts. So frankly the tank should be able to handle it at full (once it is stable). And the Zoas don't seem to really like the new reduced lights (or something else, I dunno).
I have one 5" magnificent Foxface, one Filefish, a Starry Blenny, and a purple Firefish. Plus the corals and inverts.
I feed a mix of frozen (depending on the day some reef frenzy and a bit of pe Mysis, or a bit of Hikari brine shrimp) and Reef Nutrition foods (R.O.E at the moment) . If I'm being honest it is probably a bit over two cubes a day. Every other day there is some phyto mixed in as well.
We do spread that out throughout the day though. A bit here and a bit there, so pretty much all of the visible food gets eaten. Same with the strip of Nori I put in in the morning.
The last couple of weeks I also mixed in some clams. So a couple of days a week, I would put in half a live clam (well, live from the grocer, then frozen overnight, then thawed in the fridge in some tank water). I would cut back on the other food those days. Everyone seemed to really like it and it overlapped with the reduction in GHA from other stuff. But I've paused that for a bit until I can figure things out more.
Oh, at the same time I put two actual live clams in the sump. About a month now and they are still alive and, presumably, filter feeding. I'm watching them closely to pull them out if needed. I know
@saltyfilmfolks has some... Not sure what the signs are for a dead clam. I know these ones aren't yet as they are sometimes open a bit, and then closed again.
Oh, also have a sea cucumber. He has been in the main tank for 4 months or so. Shortly after he arrived he climbed up under some live rock and has stayed in the same spot (moving a little day to day) ever since... Lazy.
Cheers, Tony