Refugiums and Macroalgae-the Good, the Bad, the Ugly

[Slakker]

But increase the amount of waste being returned to the system by bypassing the skimmer...

[melev]

I ran my 55g with the return pump feeding my refugium and it did quite well that way for two years. There are plenty of nutrients in the water, and if your refugium actually looks starved, there's no rule you can't drop in some flake food once a blue moon.

[Paul B]

You know, come to think about it... I was worried about a dwarf lion eating some of the larger pods in the fuge...

A lionfish will not eat pods unless the pods are an inch long and I never saw a one inch pod

[Siffy]

Maximizing macro growth at the expense of skimming seems counter intuitive. They preform the same task, nutrient removal, but refugiums also remove beneficial elements from the water as well. And with the chemical reaction inside a skimmer taking less time than the biological functions inside a refugium, I'd give the skimmer first chance at water and the refugium a controlled low flow environment. Plus, like melev said, the water everywhere is essentially the same with only a few exceptions, but it all has nutrients in it.

The skimmer can remove the things that break down and turn into nitrate and phosphate, and it can directly remove organic phosphate. I'd rather have that stuff removed from the water as quickly as possible and then leave what's left that the skimmer cannot remove to be taken up by the macro algae(s). If everything passes through the refugium first, it has a chance to settle and break down and the skimmer might never even see it. Sure it's fine that the fuge can remove it from the water column after it's decomposed, but if it's removed before decomposition then the life in the refugium is forced to concentrate on the compounds that cannot be removed chemically.

[mrkalel]

Originally posted by Paul B
A lionfish will not eat pods unless the pods are an inch long and I never saw a one inch pod

Sounds good... Whats everyone's thoughts on dwarf or regular lions?

[Siffy]

Whichever they have a prettier of in the store. I saw a purple dwarf one I wanted bad a couple years ago.

[Slakker]

IIRC dwarf lions are more difficult to get to start eating.

[mrkalel]

Do you guys think that it will be a problem with my two eels?...


I know I know... I'll post that ques. in the other forums....

[paulsilver]

For my 210 reef system, I have two sorts of refugium sort of... I have a 90 gallon sea horse tank, which has a deep sand bed of about 5 inches, and lots of rock, although of course it has sea horses in it, and a mandarin... and I have a 75 gallon true refugium, with a similar DSB, about 20lbs of live rock rubble, and a big ball of Chaeto... the water in the system is VERY stable, has 0 nitrates, almost 0 phosphates, Ca at 450 and Alkalinity at 3.6 m/eq

In fact, only the 75 counts as a true refugium, but the sugar fine DSB for the seahorses has reduced phosphates and nitrates since it was added, even more than the refugium, and the refugium now allows me ot feed the fishes in the reef and the seahorses much less than previous.

For the record, there is also a 29 gallon tank connected to this system, which has a larger grain sand bed of about 3 inches, and houses a couple of odd crabs that would not work as well in the reef or with the seahorses.

I find the refugium very productive of pods, and other stuff, and once a week I thin the algae, and fluff it up, which sends into suspension a bunch of bacteria and detritus etc. which gets circulated through the system... so I dont feed my corals at all any more. Just some vitamins and amino acids, via EOS...

I do run a Ca + Reactor, and a Kalkwasser system for top off water. But with the coral population and the clams, this is needed, DSB or not...

So, I think I use the system as both a generator for live foods and for biodiversity, as well as for nutrient export... I have tried Caulurpa too but try to avoid it in the refugium at this point... it does grow "well" in the seahorse tank, where it is also harvested about once a week or so.

Comments?

[Slakker]

This thread got me thinking while I was at the LFS...but I don't think an eel would be happy in my little fuge area

They had a really active younger Tiger Moray that was really, really alert. I was leaning over the tank to get a good look (stupid idea) and he actually lunged out of the water at me.

I was tempted to bring him home right then and there...LOL

[paulsilver]

Nothing quite like a lunging moray... but I think the point of a refugium is to NOT have any predators in there... yes?

[Slakker]

I guess not, as long as they don't prey on copepods

[paulsilver]

well... it would certainly be an interesting animal to have... I was just joking, since I actually have seahorses in one "refugium" style set up...

[Slakker]

The little guy was so active and fun to watch...had I the space for a tank him, I might have brought him home.

[Aquarist007]

Originally posted by Siffy
Maximizing macro growth at the expense of skimming seems counter intuitive. They preform the same task, nutrient removal, but refugiums also remove beneficial elements from the water as well. And with the chemical reaction inside a skimmer taking less time than the biological functions inside a refugium, I'd give the skimmer first chance at water and the refugium a controlled low flow environment. Plus, like melev said, the water everywhere is essentially the same with only a few exceptions, but it all has nutrients in it.

The skimmer can remove the things that break down and turn into nitrate and phosphate, and it can directly remove organic phosphate. I'd rather have that stuff removed from the water as quickly as possible and then leave what's left that the skimmer cannot remove to be taken up by the macro algae(s). If everything passes through the refugium first, it has a chance to settle and break down and the skimmer might never even see it. Sure it's fine that the fuge can remove it from the water column after it's decomposed, but if it's removed before decomposition then the life in the refugium is forced to concentrate on the compounds that cannot be removed chemically.

If that what was implied from my post it certainly wasn't the intention.
Quite often the flow through the sump area is faster then the skimmer can handle resulting in unskimmed water being returned to the tank.
My intention as in my system is to help a "weaker" skimmer be more effective by lighting the load it has to process. Thus by splitting the drain between sump/skimmmer and refugiums this allows regulation of the flow to each and thus maximize the the skimmmer and the refugium.
I realize the skimmer removes more then just phosphates and nitrates then a refugium but isn't the trade off worth it?
You guys are the experts , certainly not me--- let me know or take another look I my system which I "thought" had been tweaked to maxium effeciency

[Paul B]

Maximizing macro growth at the expense of skimming seems counter intuitive. They preform the same task, nutrient removal,

Not exactly, A skimmer only removes these wierd molacules that have one side attracted to water and the other side repelled by it.
They also accidently remove whatever is stuck to the surface tension of a bubble. Macro algae will only remove disolved nitrogen, phosphorous, and some ammonia.

No chemical action takes place in a skimmer using only air.
The removal is really mechanical having to do with surface tension.

The best thing is to have both a skimmer and a refugium.
I also do not think it matters much where the water goes first. Much of the water flowing through a refugium or skimmer is not affected at all. These things are not anywhere near 100% effective. Water makes many passes through a skimmer and refugium to make these devices effective. They are not like a RO or DI where one pass is nearly 100% effective.
Water flowing through a skimmer only has some of it's pollutants removed that come in contact with a bubble and a bubble can not remove all the pollutants in the time it takes for the bubble to burst. A refugium also only affects the water that actually touches the algae and even then, only a tiny portion of chemicals will be removed with each pass.

Capn, I have bean to the sea and I have smelled fish

[Aquarist007]

[i


I find the refugium very productive of pods, and other stuff, and once a week I thin the algae, and fluff it up, which sends into suspension a bunch of bacteria and detritus etc. which gets circulated through the system... so I dont feed my corals at all any more. Just some vitamins and amino acids, via EOS...

Comments? [/B]

I am with you here--since the second refugium has matured my corals have taken off with rapid growth--new heads ect ect
I have cut back the feeding to maybe only once a week and the water changes to maybe six weeks now.

[paulsilver]

I still do a water change once a week or so, about 40 gallons each time, but then that is only 10% weekly... not so bad really...

[kar93]

Do any of you prune your macro regularly or have a big forest going on under there?

[paulsilver]

I do a pruning of about 33% of the growth about every two weeks in the refugium... Chaeto... pull some out, and squeeze the rest to get the detritus moving... I find it grows faster this way, and I prevent the dead spots within the ball that many have described... I also prune out about the same percentage of the Caulerpa in the seahorse tank, keeping it fresh and growing...

If not, it will stop growing as much, die back releasing those nutrients back into the tank, and cause havok with various substances that inhibit coral growth, etc. etc. etc.

I believe that if you are going to have a refugium or algae scrubber, you have to cull the herd, so to speak, and pull out some of the algae each week or so... otherwise it is not exporting the nutrients, but rather just tying them up for a short while until the algae dies back and releases them back into the water.

Just my two cents.

[ReefEnabler]

"...some of the algae each week or so... otherwise it is not exporting the nutrients, but rather just tying them up for a short while until the algae dies back and releases them back into the water."

I think you are definitely right.

[fred fishstone]

Originally posted by kar93
Do any of you prune your macro regularly or have a big forest going on under there?

I remove about half of mine every two weeks. It's a very small refugium (about 3.5 gallons) but the chaeto grows well. I break it up into several tennis-ball size clumps, which seem to make it grow faster -- more exposed surfaces, I guess. Whens there's too much for it to tumble freely, it's time to prune!

[paulsilver]

I have been to the sea too, and those fish really do smell...

As for the discussion on the skimmer action above: I agree that the two functions are complimentary... but perhaps for a different reason: the skimmer removes ions and polar molecules, as Paul B says, in other words, particles that have a polarity, like water, are attracted to the air water interface because of the polar nature of the water and the particles... These particles are usually organic, which is to say, they are precursors to the particles that through oxidation and reduction, end up forming into Nitrate, Phosphate, Nitrite and Ammonia. But also ions are removed, such as Iodide, for example, and other trace elements. So, the skimmer removes these things BEFORE they break down into "nutrients"

Then the algae scrubber comes into play, taking out whatever is not removed by the skimmer and ends up as nutrients N P & A, etc. the algae use these for growth, along with other substances (carbon, calcium, magnesium, etc.)

So using both is the best answer, in my view, as far as scrubbing the water...

But...

The other aspect of "refugiums" is that they provide a predator free environment that allows pods and other small creatures to flourish. These are great food items for the fish, clams, corals, and other inverts.

So, with that in mind, I do find that the sequence of placement of the refugium does matter to some extent, in so far as we want the little creatures and single celled algae to make it to the main display, and in my case, also to the seahorse tank. So I have the outflow from the sump split, going to the main display, the seahorse tank, and the 20 gallon tank, and the seahorse tank drains into the refugium, which drains into the sump... this way, the critters only have to make it past the sump and the pump once, and then into the displays.

I would argue for the distinction between a refugium and an algae scrubber to be used, and to be a bit soft on what we mean by an algae scrubber... a tank with a big ball of chaeto counts, in my view.. but if there are any predators in it, then it is not a refugium, although it may be an algae scrubber.

Not sure how clear my writing is on this, but I hope it is clear enough... and I hope it helps.

[paulsilver]

I imagine kar93 or Kane up top might have a better understanding of the chemistry than I do... but I have had my courses, and have read up on the topic... I think I understand... but then, perhaps I am missing something big and just dont know it.

[JohnL]

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