Chaeto dying off

[Clavius]

Two weeks ago I received my chaeto reactor with chaeto start culture. (Ultra Reef Algae Filter) And I immediately started it on a 16 hour cycle, opposite to the tank lights.

The problem is that the chaeto grows very slowly, and is even dying off. Parts of it is becoming really slimy.

My phosphate is just under 0.03 and Nitrate is at 1, so there should be at least enough nutrients to sustain - or even grow - the chaeto that I have. Light source and pump were part of the set that I purchased. It has a 2w led light at 3000k. And the pump is 700 liters/hour. I do not have algae elsewhere in the tank. Save some brown dust on the sandbed.

What else could I be doing wrong? Could it be that I just don't have enough nutrients? Should I run the lights 24/7 like some do with refugiums?

[SantaMonica]

Almost certainly it's the weak light compared to the low nutrients. If it's really 2 watts, and it's 3000k which has little red, then that little bit of red light stretched along the long tube will not be enough photosynthesis to out-pull the nutrients out of the water. And that's at the part touching the light; one cm away it is much weaker.

Easiest thing to try is a red light string of 5 watts.

[Clavius]

Almost certainly it's the weak light compared to the low nutrients. If it's really 2 watts, and it's 3000k which has little red, then that little bit of red light stretched along the long tube will not be enough photosynthesis to out-pull the nutrients out of the water. And that's at the part touching the light; one cm away it is much weaker.

Easiest thing to try is a red light string of 5 watts.

Many thanks! It's very easily replaced in this model reactor that I got. The center is a hollow tube in which different types of string lights can be inserted.

[Clavius]

One more question... Would lighting the Chaeto 24/7 make any difference whilst spanning the time needed for my order of red 5 watt leds to arrive?

[SantaMonica]

I don't think so. A little rest usually always helps.

Make sure the power supply comes with the new lights. Or make sure the current power supply can handle 5 watts.

Get 660nm reds.

[Clavius]

So, my 660nm red light strip finally arrived two days ago. I immediately installed it and put in a fresh batch of chaeto that I got... The next day I discovered that the central tube of the brand new reactor that holds the lights was cracked. It seems cracked from the inside; on the outside I cannot actually feel the cracks. Luckily no water is entering the central tube. I've requested to have it replaced under warranty.

My first thoughts were that this was due to extra heat... But when I take out the strip, hold in in my hand and turn it on, it only feels warm-ish. Even when I hold it tight for a while. Besides, wouldn't the water flow through the reactor actively cool it anyway? Just bad luck I guess.

[SantaMonica]

I've heard of these cracking a lot. The expansion on the led side, and the contraction on the water side, stretch the glass.

[Clavius]

I've heard of these cracking a lot. The expansion on the led side, and the contraction on the water side, stretch the glass.

Any tips on how I can prevent this in future? (When my replacement light tunnel arrives.) I was thinking to increase the flow through the reactor so it cools better. From 700 liters an hour to 1500 liters an hour. (180 us gallons to 400 us gallons an hour.) The latter is the perscribed maximum of the reactor. Or would that only make it crack quicker because of the increased hot/cold difference?

[SantaMonica]

It would crack quicker.

[isenhart]

I would put the lights on the outside.
7402

[Clavius]

Almost certainly it's the weak light compared to the low nutrients. If it's really 2 watts, and it's 3000k which has little red, then that little bit of red light stretched along the long tube will not be enough photosynthesis to out-pull the nutrients out of the water. And that's at the part touching the light; one cm away it is much weaker.

Easiest thing to try is a red light string of 5 watts.

Just thought you'd like to know that you were absolutely right. The Chaeto is growing very well now. Almost doubled in only a week time! Even though I'm only turning on the lights when I'm at home and not asleep because of the cracked tube. It's cracked, but still doesn't let water in. (I know I know, not smart. I just want to keep the chaeto alive until I get my new - actively cooled - solution arrives.

[Clavius]

I would put the lights on the outside.
7402

I have a reactor that stands in the sump though. The water passing through the reactor just flows over the edge and down the outside again. So, that's not a possibility for me.

[SantaMonica]

And even if the glass leaked, the lights won't short out because they are on a (usually) isolated power supply.

[Clavius]

I would put the lights on the outside.
7402

Btw, have these been known to crack also? Because, on second thought, this just might be a much better option for me after all...

[SantaMonica]

Those strip lights don't crack but they go out a lot. At least they are cheap.

[Clavius]

No, I meant the plastic of the external media reactor, wouldn't that crack? Just like the light tunnel of my reactor did?

[SantaMonica]

I've only heard of those crazing, not cracking.

[Clavius]

Still, even with the more powerful light and the correct spectrum, the chaeto still won't stay alive. I've restarted with fresh batches 5 times now. Meanwhile experimenting with lighting period and flow. But it just turns to snot.

Any suggestions?

[SantaMonica]

Since your nutrients are low, try feeding three times as much for a week and see what happens.