Acropolis

[JiaEn 30]

Crocea clam on the sand bed spawned yesterday. 

I take it as an evidence of sufficient PAR on the sandbed,  and the clam is doing well. 

There is growth ring as well. So hopefully it will get bigger. 

[JiaEn 30]

One benefit of having a large open space is to enjoy the feeding of fishes. 

The labyrinth in the main rockwork provide space for the fishes to high.  Since there is ample shelter at hand,  fishes are relaxed and willing to venture out to the open to feed. 

When the fishes dart out to feed,  it's a great opportunity to observe them without obstruction. If any fish were to show signs of hesitation at feeding,  it's an alarm to be investigated further. 

 

P. S.  I cannot be happier about those Fauna Marin pellets. The fishes seems to be able to digest them very well (based on the observation of their faeces). The feed conversion appears to be high too.  Even as I increased feeding, there is no increase in nutrient level in the tank. 

[JiaEn 30]

Managed to fix up the cabinet doors just before CNY. 

A hooded aquarium prevents light spill and glare into the room,  it also slightly reduce the noise from fans and water flow. 

The downside of a hood is heat. The enclosed space prevents the lights from cooling properly.  For the longetivity of the lightsets, I decided to vent the cabinet doors.  Although this takes away the seamless look, I can be assured that the leds won't degrade before their time.  A trio of dc fans actively push the hot air out. 

 

If I were to start from scratch, I would opt for a chimney style convection vent at the back of the cabinet, that would offer good ventilation without disrupting the facade. 

 

[JiaEn 30]

A Case for Chromis

Blue-green chromis (chromis veridis) is often viewed as an underwhelming fish.  Its color is not luminous; its size,  modest.  Generally if you think about a background fish in the reef,  chromis is exactly what you have in mind. 

As I observe the fish feeding today, I took a second look on the chromis. I realised they are not that bland after all.  

 

Scales

In an aquarium dominated by tangs,  aquarists can quickly forget that fishes actually have scales.  The chromis have small but distinct scales,  forming a lattice pattern on the flanks. 

 

Display

Chromis displays as often as the more flashy wrasses. The male have trailing streamers on their caudal fins,  and subtly flashes their dorsal ray to signal dominance. This tiny gesture is often unnoticed unless the aquarist watches closely.

 

Color

The blue green chromis does not have mind bending colors of wrasses.  However,  a healthy fish will exhibit bold,  deep colors. As aquarists,  we can color up fishes just like we color up corals: by giving them good environment and nutrition. 

 

Behavior

Further observation of these fishes can uncover a lot of interesting behavior. How they seek refuge in the corals;  how they bricker among themselves, how nip on the colony of stylophora so that the new growth will be open enough for them to hide inside.  All these are not as impressive as the nuptial dance of wrasses,  or the sparring of the tangs,  but they offer the same insight into the reef live. Which is very different from our own. 

 

All these are true if the chromis is healthy, and the environment is not stressful for it. I guess after all, this is a case for healthy fishes. Give the average fishes a chance, keep them healthy, and let them impress you. 

Afterall,  a healthy chromis looks 100x better than a sick peppermint angelfish. 

 

[JiaEn 30]

Body Language of a Fish

 

As I observe the fishes in the aquarium,  it becomes clear that fish show their disposition through their body language. By looking at how the fish compose itself, we can have a good understanding of it's condition and mood. 

I will attempt to make some notes here. 

 

Eyes

The eye of the fish is a clear indicator of the health of the fish.  Of course,  a cloudy, injured or popped eye indicates problem with the fish,  but there is more to that. For healthy and calm fish, there is a glint in the eyes, the fish is looking, focusing on somewhere.  If a fish has a blank look,  something is very wrong. 

 

Orientation

The body orientation of a fish paints a clear picture of the health of the fish. Water resistant is much higher than air, it's fundamental for fishes to maintain the posture of least resistance in water. Regardless if a fish is hovering,  or zooming around,  it should not wobble around. Awkward flailing of fins and body signifies a fish losing its muscle prowess or coordination. 

When taking into account of the defence mechanisms,  things gets more interesting. Acanthurus have their caudal spikes,  while angelfish and butterfly have their dorsal spines. These are their defenses. When being threatened,  they point these defensive tools towards their aggressors. Tangs will point the tail towards each other,  while a copperband may lower it's head and raise its spine. 

Such defensive can cause some hurt,  but these are not the tools of aggression most of the time. If you examine the bully and victim,  you will find that most of the injury are effected by the mouth. 

 

Fins

Spreading the fins of the fish make it look bigger and more intimidating. It is an effective way for fishes to exert dominance,  as well as a defence mechanism.  Most of the dominant fish will periodically flash their dorsal fin.  I suppose this is an action to remind the tank mate its alpha status. 

When a new fish is introduced to the aquarium,  due to the stress of the new environment,  it will likely fully spread its fins. In my option, this can cause existing residents to mistake this for aggression,  and lead to subsequent confrontation. (This is my theory why new fish almost always gets a beating.  It's like a in those action movies,  where the protagonist barge into a room and draw a gun for self defence,  only to have the guys in the room aiming the gun at him) 

 

There is more! 

A fish can show many colors. Cowering, confident, night, excited, angry.  By looking at the color of the fish, one can know their mood. 

A fish has some regular behavior,  when they are not doing those enough, it may be a cause for concern.  For instance, tangs spend a lot of time grazing and a bit of time to defend it's territory. If a tang does not graze most of the time,  then something is wrong. 

A fish maybe breathing hard.  Is it because of exertion during aggressive display?  Or is it because of other health concerns like parasites? 

 

I want to be comprehensive, but I can't.  There are so much fine details, as well as useful informationc in fish behavior.That's why I feel it's important to watch the fishes,  and speak their language. Then we can be more competent aquarists. 

[JiaEn 30]

The Lanceolatus Group Wasses

I have two wrasses from the Lanceolatus group.  Lanceolate means spear-head shaped in Latin. So it's not a leap of logic to expect fishes belong to this group have enlongated,  tapered caudal fins. Such as thus gorgeous splendid pintail wrasse from Reef Builders. 

Image from reef builder (https://images.app.goo.gl/FcuNVPifyXA25Kdr6)

However,  despite the conspicuous pintail, this wrasse is not in the lanceolatus group. Surprise surprise,  the defining characteristics of a lanceolatus wrasse is not in their spear like tails,  but in their dorsal and cheek stripes. 

 

Two Lancers,  One Lance 

These are the two wrasses in my tank from the lanceolatus group. 

The top is roseband wrasse (C.  roseafascia),  the bottom one is flame wrasse (C.  jordani). Although flame wrasse does not have the name sake spear tip tail,  it does have very distinct dorsal stripe,  as well as a stripe on it's cheek. 

I have kept this flame wrasse for slightly over a year. It changes from a tiny female to a terminal male now.  It's still capable of more growth in terms of size though. 

The roseband wrasse is with me only for a month. I bought it as a male specimen and fortunately there is minimal aggression between the two. 

The environment is not the most ideal for them though. Because these wrasses hail from the very deep water environments. So the higher temperatures and the bright light in the aquarium is perhaps not the best for them. They are eating well and relaxed. So all is good for now. Both of these can grow to impressive sizes,  and I'm looking forward to that. 

 

 

[JiaEn 30]

The Problem of Different Growth 

I had to modify my reefscape today.  This is because the difference in the growth rate of corals. 

The digitata,  which is front and center,  grows rapidly. At first,  this bunch offer a bright body of color for the young scape. Now,  it start to encroach on the top level,  and threaten to over take the microclados and millieporas eventually. 

 This will not do. 

I pull the whole rock,  and placed it on the sand bed. The digitata is so brittle, the rock now looks like just had a hair cut.

Oh well,  at least they grow fast. 

I have not finalized the placement of the digitata rock. Probably will shift it soon. 

[flowy 11]

On 1/16/2021 at 8:46 AM, JiaEn said:

Designing proper flow for a mixed reef has its challenges. On one hand,  acropora species enjoy copious random flow; on the other hand, fleshy LPS may suffer when blasted with water. These animals evolved to make the best use of their environments.  Now that they are in my aquarium,  I need to try and provide the suitable flow for them.  

A few consideration for flow:

1. A mixture of flow style is beneficial. Have a gentle "gyre" flow to circulate the water,  and a localized strong random flow to cater to sps corals. 

2. The output of a random flow pump decreases rapidly as distance gets further.  That's why a large aquarium requires wavemake on both sides. I would like to keep the second viewing side clear of equipment, so something else must be done. 

3. Rocks and corals create obstruction to flow. It's important to consider this effect with the fully grown colony in mind. 

Presenting, the flow schematic of my Acropolis. 

The return nozzle (red) sits at the top left side. Since the return pumps operate at constant flow rate,  the continous operation generates a gyre flow (white). This flow is relatively low speed except at the water surface near the nozzle. Thus fairly condusive for lps in general. 

The forward flow is far above the rocks and corals.  This minimize flow obstruction and ensuring the gyre flow can be set up properly. On the other hand,  the return gyre flow at the bottom is break up by the rock scape. Some will follow the contour of the rocks and form a upswell, while some will flow around the rock pillars and form back Eddie current. 

Supplement this flow is a pair of jebao wave makers (blue). The operates at randome flow mode. Supplying strong and varying flow (green)  to the core of the rock scape. The open rock work structure ensures the flow goes as far as possible.  The strong random flow reaches about half way into the aquarium. 

There is a region with relatively less flow,  on the right side of the aquarium at the mid level.  This is ok as it is a void space without any corals or rock work. 

Overall I think the flow design is satisfactory. Do let me know your thoughts. 

Hi JiaEn, regarding deciding of your flow, how do you decide what is suitable and efficient for your system to maximize flow to the corals yet not blowing at them directly, as i am stuck on deciding how to place my wavemaker  and i am sure that rockscapes also plays apart in that as well as future proofing when corals "grow"

[JiaEn 30]

@flowy thanks for reading!  I struggled with the flow question for a fair bit especially since I want to limit the equipment and outlets to a single side. 

 

The immediate choice is to try and turn up the wm and direct it at the main rock scape. Like this simple sketch

The red cross is the wave maker, the  black blob is the rock work.  Before flow hits the rock,  the velocity is very high,  potentially too much for the corals directly impacted by it. When the flow hits the rock work,  it's redirect at different directions, velocity is also deacreased. On the other side of the rock,  there may be some eddy flow, weaker and random.  And further downstream,  the flow rapidly decreases.  This implementation produce mostly very high or very low flow zones. The efficiency is low. 

 

I implement my flow design slightly differently. 

The wave makers are not directed at the rockwork. Instead,  the are pointed in/through open spaces around the rock work. Unobstructed,  the main flow caused by the wavemaker does not deteriorate rapidly. My Jebao slw30 push usable flowrate at least to about 2/3 of the tank. 

The good thing about this design is that, the rock work are supported by the entrained flow (green arrow). Due to the Bernoulli's Principle,  the pressure at the high flow region is low. So the unobstructed flow draws in water from surrounding.  This entrianed flow is sufficient for the corals,  even on the opposite side of the rock work. 

 

Only time will tell if the current configuration is adequate when the coral grow even denser and bigger. But I don't see any reason this won't work for the long run. 

[flowy 11]

[mention=28684]flowy[/mention] thanks for reading!  I struggled with the flow question for a fair bit especially since I want to limit the equipment and outlets to a single side. 
 
The immediate choice is to try and turn up the wm and direct it at the main rock scape. Like this simple sketch

The red cross is the wave maker, the  black blob is the rock work.  Before flow hits the rock,  the velocity is very high,  potentially too much for the corals directly impacted by it. When the flow hits the rock work,  it's redirect at different directions, velocity is also deacreased. On the other side of the rock,  there may be some eddy flow, weaker and random.  And further downstream,  the flow rapidly decreases.  This implementation produce mostly very high or very low flow zones. The efficiency is low. 
 
I implement my flow design slightly differently. 

The wave makers are not directed at the rockwork. Instead,  the are pointed in/through open spaces around the rock work. Unobstructed,  the main flow caused by the wavemaker does not deteriorate rapidly. My Jebao slw30 push usable flowrate at least to about 2/3 of the tank. 
The good thing about this design is that, the rock work are supported by the entrained flow (green arrow). Due to the Bernoulli's Principle,  the pressure at the high flow region is low. So the unobstructed flow draws in water from surrounding.  This entrianed flow is sufficient for the corals,  even on the opposite side of the rock work. 
 
Only time will tell if the current configuration is adequate when the coral grow even denser and bigger. But I don't see any reason this won't work for the long run. 

Wow thanks for ur detailed and prompt replies with explanations, really helped me understand. But one question lies, does turnover rate really matter?, or as long as the corals (Polyp extensions) are happy, all is good?


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[JiaEn 30]

Turnover of the Aquarium

The flow of the aquarium is designed to serve three different equilibriums. From the largest to smallest scale,  they are DT-sump, DT,  and Boundaries layers. I will attempt to explain each of them and their significance in aquarium keeping. 

 

Boundary Layers

On the very tiny structures,  such as coral surface, the viscosity and inertia of water interacts to produce different flow patterns. Interestingly, corals grow various papillae and ridges to engineer the flow around it.

The reason why this microscopic flow is important is,  as corals use up nutrients, give out waste,  consume or release oxygen,  there is a boundary layer. This could due to the flow characteristics, it could also be limited by diffusion.

One can think of the boundary layer as a limit of how fast corals exchange materials with surrounding water. Therefore the water movement needs to be sufficient so that the boundary layer is not overly thick. So rather than saying the flow must be high/random etc,  I would say that the flow for the corals must be perfusive - sufficient to maintain the correct thickness of the boundary layer on every part of all the coral. 

We can only provide a certain flowrate.  How can we meet the need of all the corals then? Surely they have different flow requirement? 

Yes they do.  And no,  we don't need to worry too much, sometimes. 

 

Flow Engineering of Coral

Imagine some one fire a tic tac using an air rifle, and you try to catch it using two fingers. Easy task?  Corals pretty much need to do this on the daily basis to feed. Turns out, they are good at managing this. Not through flash-like reflexes,  but through tried and true engineering.

Corals such as Montipora grow interesting microstructures to modulate the flow at the surface. Many Acropora alters their polyp distance and branch density to keep the flow optimum. Most amazingly, many millipora grows the entire colony in such a way that the top of the colony slows down the flow,  and redirects them into the deeper core of the colony. 

That's why taking a full colony and transplant it in the tank often result in less than stellar results. The growth was an adaptation to a different environment. Most of these colonies will take time to grow and eventually adapt to the new environment, often with vastly different form. 

Taking a frag or a mini-colony, and allows it to grow out,  will allow the coral to grow based on the available flow. In my opinion,  there is less problem down the road. 

[JiaEn 30]

Turnover of the Aquarium (II) 

After taking care of the tiny details (hopefully) let's look at the bigger picture

Display Tank Turnover

In addition to have sufficient flow to keep the polyps well supplied, thought must be given to ensure the water in the display tank is as homogeneous as possible. 

The flow in the display tank should preventsm the formation of anoxic pockets. It should also reduce the accumulation of detritus. It's difficult to say for sure how much GPH is sufficient. In my opinion,  if detritus don't accumulate,  then the bulk movement of water is sufficient.  I'm of the opinion that the gyre style of flow is the most effective way to achieve good homogeneity in the display tank. 

Display-sump Turnover

This is another tricky topic.  I use to think that by pushing a lot of water through the sump, I am able to supercharge the filtration system. Now I believe I was very wrong. 

The effectiveness of many filtration methods, such as biomedia, protein skimmer,  GFO reactor,  depends mainly on residence time.  When water pass through the system too fast, the residence time is too short. Many of the desires processes cannot be completed fully. 

Therefore,  the turn over of the dt-sump should be set  according to the required residence time of the filtration system. Not too high such that water exits the sump too fast, also not too slow such that the sump become a very different environment compared to the display tank. 

I would look at the skimmer rating,  and adjust the turnover from there. 

[JiaEn 30]

@flowy hope the previous two posts are relevant to the discussion. Flow is a challenging topic because it's complex and hard to measure. 

Polyps extension can be a good sign,  but it's not a guarantee the flow of the tank is appropriate. 

[flowy 11]

[mention=28684]flowy[/mention] hope the previous two posts are relevant to the discussion. Flow is a challenging topic because it's complex and hard to measure. 
Polyps extension can be a good sign,  but it's not a guarantee the flow of the tank is appropriate. 

Thank you for your time and the detail explanation provided!, appreciate it!!


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[JiaEn 30]

Part of the reason why I try and write down all these understanding is actually for two selfish reasons. 

1. To keep track of my reefing understanding. What I know about reefing now is a lot different from what I knew one year ago. And I would like to be able to look back a few years down the road,  and see if/how my understanding has improved. 

2. More importantly,  I hope to have reefer challenge my assumptions. There are so many things which we take it for granted, so much so that it can become a blind spot for me. By writing things out and trying to justify my points with logic and evidence,  it is possible for others to question and disagree. 

I'm hoping to understand reefing better  through these discussions. It would be great for my Acropolis to be like the original, a symbol of open discussion and debate. 

[JiaEn 30]

Coral Fluorescence 

Coral fluorescence is one of the topic which puzzles me greatly. The florescent proteins and zooxanthellae density are all well studied. But what we do in the hobby, or rather, what works in our hobby, is not well explained by the science behind coral fluorescence. I will attempt to compare the science with practice,  then perhaps we can see if there is any missing pieces of the puzzle. 

 

Coral Fluorescence in Hobby

When it comes to reef keeping hobby,  the ways to achieve good fluorescence for corals,  especially SPS corals,  are well established.  We start with water containing very low level of nitrate and phosphates.  Then we attempt to keep the pH high,  and the "big 3" elements stable. Next,  we use intense light and vigorous flow. Finally, we feed the coral,  with planktonic mix,  amino acids,  and dose trace elements to achieve shining color. 

For most of us,  this works well. 

 

Some of these factors are easy to understand. Having stable water parameter close to the reef environment definitely reduce stress for the corals.  Giving suitable food in the form of planktons and amino acids ensure corals have sufficient nutrients. The intense light encourage the formation of florescent proteins to protect the coral. All these are well and good. 

 

The problem is with the trace elements. 

 

On one hand,  dosing trace elements (such as FM colors, Redsea ABCD)  leads to improvements  in coral color for me (and many others); on the other hand, the idea that trace elements is needed by the corals to form florescent proteins is highly debatable.

In the next post I will list down some facts,  maybe one day we can truely know the mechanism of coral fluorescence.