Pale SPS

[JustinReef]

Having a tough time figuring this one out.

IM nuvo 10 G
AI Prime HD light, set to about 3/4 power, roughly 10" off the water
8lbs LR
Back chambers : Marine Pure spheres, one nano size bag Chemi pure blue

Temp: 77.5-78.5 (Apex)
No3: 2.5 (Salifert)
Po4: 0 (Hanna Phosphate checker Hi-713)
SG: 1.025
Alk: 8.6 - 9.2 (3 months) (Hanna)
Ca: 400 - 420 (3 months) (Salifert)

I feed pellets once a day, sometimes once every few days. I do weekly 2G water changes, based on actual water volume this is probably about 25%.

Most SPS I put in this tank go very pale over the course of about 3 months. They grow well, encrust, have ok polyp extension but lose color slowly. Originally I thought it may be from too much light but I am not convinced that would be it, most of the frags I get come from high light aquariums.

I highly doubt my phosphate is really 0 based on this being a skimmerless, all in one tank. The nitrates are pretty much where I would like them.

I do have a few corals that are actually darker than they should be which makes this even stranger. My Red planet is kind of a dark purple, I have a few Purple bonsai's which are brownish/deep purple and a blue unknown acro that went to a darker blue in my tank. Then some of the most pale corals are: Green Hulk, Red Dragon, Red Setosa.

I have what I thought was cyano but now seems to be something else, it is deep red but more 'stringy' than usual cyano. I do not ever see ANY algae on anything, ever. Coraline also does not grow.

I'm pretty confused. Ideas?

[JustinReef]

Forgot...

Flow: Aqamai KPS and Tunze nano 6040 (so much flow)
Not really much sand, almost barebottom

[pisanoal]

How many fish?

Even though you say you doubt your tank is actually 0 phosphate, you go on to say you never see any algae. Id guess low nutrients. How often dobyou clean your front glass? Also your alk could be dropped to 7.5 or so.

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[JustinReef]

Originally Posted by pisanoal

How many fish?

Even though you say you doubt your tank is actually 0 phosphate, you go on to say you never see any algae. Id guess low nutrients. How often dobyou clean your front glass? Also your alk could be dropped to 7.5 or so.

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I have my doubts because it is the Hanna checker for the higher range. I have no doubt that the tank has very low phosphate.

I think if I did not have a bit of a weird cyano-like growth that sometimes grows on the bottom of the glass, I would only have to clean it once a week.

I've always kept my alk around 8.5 and have been planning to drop it around there but why do you recommend 7.5?

[JustinReef]

Oh, 2 fish. One Cardinal and one Randall's Goby. Keep in mind this is only about 8G of water.

[pisanoal]

The consensus seems to be, especially for lower nutrient tanks, the closer to NSW levels, the better for alk. If you keep it at 8.5, that is likely ok. I say target 7.5 because if you drift either way, you are ok. If you drift up much from 8.5 you are risking tip burn with low nutrients.

As for the low nutrients, if you aren't seeing ANY algae growth, your nutrients are almost surely too low, regardless of what test kits say. Its also possible that your cyano is consuming all the phos and not leaving it available for corals.

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[Piper27]

Can we see some pics of the dark and pale corals as well?

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[markalot]

Based on tests the simple answer is the acros are starving. Dirty filthy tanks = colorful acros.

8G of water? Good grief ... good luck, I was never able to find success in smaller tanks. A dirty smaller tank = algae mess. Best I've seen on smaller tanks is from those that literally fog the water with food and do fairly large water changes and cleanings to keep the tank clean.