A tale of two tanks



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Jan 28, 2018
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Hi All,

I'm going a little out of my mind with my tank and thought I should finally add a topic here to see if there is any ideas.

I have 2 tanks on the same system; a 2 foot cube frag tank and a 60 * 28 * 24 display tank. Same sump, same water.

My frags in the small tank are super happy, awesome polyp extension and great growth. My SPS in the display tank are less happy - not "unhappy" but very little polyp extension and poor growth. Some of the frags I move from small to large tank just die, they either bleach (lights?) or they just lose colour and eventually give up the ghost...

There are 3 things I see that are different between the tanks;
1. Flow
2. Lighting
3. Occupants (incl pests).

I have stuffed around with flow and lighting in the DT a lot over the years and currently we have;

3 x Radion Gen 2 Pro's and 1 x Radion Gen 1. These are ~14" off the water surface, They are a slightly modified AB+ (a touch more white) and the overall brightness is set to 60%. I've tried lower and higher brightness. Any lower and I get a lot of shadow. I do think that higher is probably too much. In comparison, the frag tank has a single AI PrimeHD on an 18" gooseneck.

The FT has 2 x chinese wave makers. Everything in there moves but nothing violently. The frags are up high and get a bit of the wave bounce back. The DT has 2 x MP40's on left and right walls and set to 90% reef crest and anti-sync. I also added a cheap Chinese gyre on pretty low across the top. Nothing in this tank moves violently but there is definitely flow everywhere with the goni and euphyllia getting lots of movement and sand being pushed around.

The FT has a lot of asterina stars, crap loads of worms and brittle stars. A few hermits and some snails. It also has a coral banded shrimp, a BTA and a pair of maroon clowns.
The DT has a lot...
Purple tang
Sailfin tang
Copperband (does not *seem* to touch coral, doesn't eat prepared food, scavenge's around rocks and sand.)
Coral Beauty (*seems* to only pick at the corals when tips are dead and have algae growth)
Single Chromis (had 7 - i swear this guy is a serial killer)
4 x yellow tail damsels (only had them for a few days, bought to ensure no AEFW's)
Sixline wrasse
Brownling wrasse
Melanarus wrasse
Royal dottyback
Yellow coral goby
I'm sure there are more ...

Lots of snails, brittle stars, crap loads of bristle worms.

I have a big ~14" diameter brittle star.

I did have a diadema urchin which has been evicted to the sump - he was chomping the tops off all my sps (I thought it was vermitids!)

As for pests - I did have some AEFW's a year or so ago but I pulled the infested colony out and dipped it. I have no signs at all of AEFW's now. I blast with a baster and between the 3 wrasses, I just think they are no longer. EXCEPT! I did have a large-ish white patch under the branches of a small acro colony. I couldn't see egg's or AEFW's at all though. Its only been on one colony so far.

I don't think water params are important because the FT success but I'll add them anyway ...

Salinity; 1.027
pH; 8.3 - 8.4
Ca; 430
Alk; 9.9 (I had a spike to ~10.5 when I switched to soda ash from sodium bicarb, I am bringing this down slowly to ~8.5)
p04; 0.2
n03; 3ppm
Mg; ~1250

I feed heavy and have been using Reef Energy Plus (50ml daily) for about 2 weeks now. I've tried lots of supplements and foods.

So, please Reef2Reef peeps, help me figure out why my DT isn't doing well.



System is 10 years old.
Weekly 80L water changes. (20G)
Total water volume ~800L (200G)
Reef Chasers Aquaculture


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Jan 28, 2018
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Sydney. Australia
Some fresh pics from tonight for reference.


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