SPS Questions

[Quaid West]

Hello! I have started to get into SPS coral, mainly Acro's. I also have a birdsnest and a couple Monti's. All of my acro's are around 1" frags. My question is why don't the acro frags show there polyps during the day? Is it normal? Or should they be fully extended most of the day? The Acro that I have had the longest has started to encrust on the rock around the plug, so they are growing, and my Monti's have grown 3-4" in about a years time! All of my LPS and softies appear healthy. I know it's difficult because you don't understand my system set up, but I will do my best to explain my water perimeters.

Tank size - 75 g
Nitrates - 15-20
Phosphates - .12
Alk - 8.2
Calcium - 430
Mag - 1300-1350
I use Red Sea Coral Pro salt with a salinity of 1.025
Temp - 77 F
I have been watching BRS video's of flow and have made some adjustments of flow. Currently I use 2 Hydro's, one of each side with a 1 minute opposite cycle for each. I do not think flow is the issue in my opinion.
I am currently running a GFO and carbon reactor, as I would like to lower the phosphates more.
No algae issues.
I do not know my PAR. I actually just rented a PAR meter from BRS and it's on the way! But my lighting isn't the highest quality. It is a Current LED light strip. Spectrum isn't something I can check is it? I can't really afford better lighting at the moment but I would love some Kessils are Ecotechs lol.

Thank you

 

[ycnibrc]

Coral feed at night also may be your fish pick it so polyps retract in the day time however birdness and Monti should have polyps during the day. look like your light is not adequate

 

[WillB]

I think there was actually a study done recently that shows that SPS corals grow best while fed during the day. The crazy polyp extension we often see at night is for gas exchange. Corals grow during the night so that is when gas exchange takes place

 

[Quaid West]

Coral feed at night also may be your fish pick it so polyps retract in the day time however birdness and Monti should have polyps during the day. look like your light is not adequate

The birdnest does show its polyps. I don't notice them on the Monti's. They are plating monti's.

 

[WillB]

OP, how old is your system? Phosphates are high. What do you test them with?

 

[Quaid West]

OP, how old is your system? Phosphates are high. What do you test them with?

System is almost 2 years old. I test phosphates with a Hanna.

 

[WillB]

What kind of coloration are you getting from your SPS? Do you run carbon?

 

[Quaid West]

What kind of coloration are you getting from your SPS? Do you run carbon?

Colors seems to be the same as when I bought them. Yes, I'm currently running a GFO and carbon reactor.

 

[jda]

SPS only NEED to use PE for gas exchange. They also can extend polyps to try and feed - nobody really knows if they can in our tanks or if what we feed them is worth the energy to catch the food. During the day, the zoox can provide and use gases that do not need much PE to exchange. At night, the coral needs to do it more on it's own. Fish and nippers are usually asleep at night too.

If you have huge colonies and the inner branches have no PE (where nothing can nip on them), then I might worry a bit. I would also worry if a normally hairy acro is not anymore... or a normally low-PE acro is now all kinda of hairy (this can mean ammonia or other element that is making gas exchange difficult).

If they are growing and have good color, then I would not worry about PE.

I have seen PE drop when nitrogen gets to 20 and above. You might consider getting that down to 5ish... or at least not letting it get any higher.

 

[Quaid West]

Thank you for your advice!

 

[Quaid West]

Thank you for the advice!

 

[Gregg @ ADP]

They also can extend polyps to try and feed - nobody really knows if they can in our tanks or if what we feed them is worth the energy to catch the food.

Just a tidbit, for anybody who wondered...

One of the cool things about the design of the coral polyp (particularly SPS) is that it allows the coral to capture food without any real use of energy.

We look at SPS polyps in strong flow and think, ‘There’s no way those little things can catch food flowing by that fast’.

Here’s what happens. As current is pushing against a coral colony, it is pushing the polyp in the direction of the flow. That results in flow hitting the base of the polyp and flowing toward the tentacles/mouth. As flow hits the flared-out top of the polyp, it creates a back-eddy of current leading right to the tentacles/mouth. Food passing by even in strong current gets pulled into the back-eddy and the polyp doesn’t have to do a whole lot more than funnel the food into its mouth.

Also worth noting that as a completely sessile organism that doesn’t have a ton going on metabolically (comparatively speaking), a little tiny bit of food goes a long way.

Fed corals are happy corals. I’m a big fan of dumping rotifers, algae, oyster and fish eggs (I use a lot of Reef Nutrition) into the tank a few times a week as it’s going into its night cycle. It doesn’t add much waste and it stays in suspension for hours.

 

[maroun.c]

Whats your fish list? its very possible you have a fish nipping on those sps.
Maybe watch the tank a bit from a distance during the day to make sure there's no nipping.

 

[Quaid West]

Whats your fish list? its very possible you have a fish nipping on those sps.
Maybe watch the tank a bit from a distance during the day to make sure there's no nipping.

Ive got a copperband that may be nipping