suspended macro in refugium

[craw_daddy]

I have just added a 29 gravity back refugium to my 125 setup. I am using a mag 2 to pull water from my main tank & it returns though a couple of 3/4" retuns to different sides of the main tank.

Here is the refugium & returns:

My question is regarding my refugium flow. I've noticed some cyanobacteria starting to thrive in the cheato. My input to the fuge is at the bottom pointing up, but with sauch a small supply pump & two 3/4" returns I think I may not be turning over the water enough.

Should I:
1) add a powerhead to improve water movement
2) change how the water enters the refugium (pipe height, direction)
3)suspend the cheato from eggcrate higher up in the water column

Any advice would be appreciated.

--Dave

 

[CaveManNOhio]

Do you have a skimmer?
I have a 125 AGA RR. I'm currently using a 30gl as a refugium. I have my drain dump in one end, at that same end is where my skimmer sits. Then I put in a baffle, I drilled 1/8" holes in rows starting 4" up from the bottom and stopped 2" from the top. I then added another baffle at the other end for the return pump, that baffle has 2 rows of 1/8" holes 2" from the top. I then put in a 4" layer of LS and 25 Lbs. of LR. Then topped it off with my Cheato & Grape Culurpra. My return pump is an Mag, 1800 GPH.

 

[ChemE]

Melev got good results from using a powerhead (see it here)

 

[CaptiveReef]

Fire up the skimmer

Fire up the skimmer

If you are not using a skimmer, then I can see cyno breaking out.


CaptiveReef

 

[Fredfish]

Hmm... Its not completely strait forward.

On water flow, I have been playing with a two tank system (40g each) with a very light bioload and very different flows in different areas of the tank.

In higher nutrient conditions (I dosed both nitrates [5mg/l] and phosphate [.2mg/l] for a while) macros seem to grow equally well in Higher flow, low flow and almost no flow areas. As nutrient levels drop off macros start dying back, first in the almost no-flow areas, then the low flow areas, and lastly in the higher flow areas.

The lesson to be learned here is that in lower nutrient conditions that many aquarists keep for their reef tanks, flow makes a difference in the level of nutrient uptake in macros.

The second piece is cyano and its optimal conditions. The cyanos that grow in our reef tanks tend to do better in low nutrient conditions. That is, when there are not enough nutrients for macros to grow well, cyano will start to bloom.

In my tank I found that cyano started to grow as nitrate and phosphate reached the lower limits of of test kits. It took over the tank when the macros completely stopped growing, even in the higer flow areas.

Of course, this is only one tank and by no means a proper scientific experiment.

... and the kicker is that I know of people that have had problems with cyano while their macros were still growing quite well, so nutrient levels may well not be the full story.

After all that, I would suggest that you increase the flow in the refugium and direct it towards your macro so that there is water movement in and around the macro algae. This should help with nutrient adsorbtion in the macro.

Also, this is a 'new' tank, and I think it will probably go through a bit localized cycling until it finds its own balance.

Nuisance algae control can be very frustrating. All I can say from here is have patience and good luck.

Fred

P.S. If you are interested in more info on nutrient uptake in marine algaes, do a search for plantbrain in the plant/algae forum. There is a ton of good info there.

 

[craw_daddy]

I have a wet/dry with a 3" dia x 20" tall skimmer built in. The main tank had a SCWD, but I recently removed it to increase flow there. I think I need more flow around the cheato too. I was wondering if it would be good to suspend the cheato on eggcrate in teh middle of the tank to get more flow around & under teh mass. When it breaks up & settles on the bottom it just becomes a detritus trap.

 

[Fredfish]

You could always segment off 1/3 to 1/2 of your refugium and create a circular flow pattern to constantly move the chaeto.

You could also add a sand sifting cuke to your refugium. I found that mine mopped up any sediments it could find, even in rocks or algae.

egcrate would get the chaeto up off the sand, but it would also interfere with flow. you could suspend the chaeto by fishing line in the middle of the water column too. Probably would not be that hard to do.

Fred

P.S. FWIW Read recently that the chaeto we keep naturally grows partially burried in heavily sedimented areas.

 

[Samala]

Freds advice is elegantly explained and covers all the bases. Its so fun to see some of the macro forum's stuff leak out into the rest of RC.

FWIW I've seen our Chaeto grow partially buried and floating in the wild. Usually around super high nutrient areas, such as those that are heavily sedimented, lagoon areas, and particularly around rookery islands (bird nesting). An iguana island had it too, though more of the second Chaetomorpha species that holdfasts than the one we tend to use in our reef exporting attempts.

>Sarah