Minimum requirements for macroalgae survival

[andy01748]

I am being conservative and following the procedure of TTM for new fish and quarantining every thing else that is wet for 72 days before transferring anything to my DT.

I have just put a bunch of inverts (turbo, margarita, and trochus snails, emerald and scarlet legged reef crabs) into my observation tank for the 72 day fallow period to guarantee non-survival of any ich cysts prior to transferring to my DT. My OT has a bunch of different macroalgae's (calupera's, dragon's breath, and others) and I know they may not survive these inverts! To make sure I don't wip out any of the macros, I have put half in a lighted one gallon HOB refugium attached to a 10 gallon tank. This tank is the QT I had just used for the two week post-TTM observation period prior to transfer of the fish to the DT. No macro predators here, and nitrates are 40 ppm, which I assume will be good for the macros.

My question is what temperature and flow conditions do I need to guarantee macro survival? The tank is still heated at 76, but will the macro die or just become dormant if I turn the heater off (to save money!)? This time of year (Boston area) I run my house heat between 58 and 64 degrees, max.

For flow, I am running a Rio 600 pump 24/7 that has a flow of about 0.25 gallons/minute. Do I need to maintain this constant low flow, or could I just cycle the pump on and off a couple of times a day to replace the water with a fresh nitrate supply? I not worried about nitrate source long term, because I can do water changes if I see a drop in the overall nitrate concentration in the 10 gallon tank. I happen to have an almost endless supply of high nitrate water!

I figure besides natural light (as the tank gets indirect light during the day), I also plan to turn on the refugium light for a couple of hours a day. I'm looking for the macros to survive, but not necessarily grow. Other caveat is if I go low temperature/no flow, will the calupera go sexual?

Just wondering on peoples' success with macros at room temperature.

Thanks in advance for your input.

 

[rbla51]

What type of caulerpa? The only type I've ever had eaten by anything was fern and it was a yellow tang eating it. As far as lighting most run between 12 and 24 hrs.A lot of diff opinions on it but I'd say 24 hr cycle. Also good flow helps, and I'd maintain a temp in the 70's to promote growth.

 

[JLynn]

I don't think that the macros will necessarily die at those lower temps, if they are slowly acclimated to them. So if you drop the house temperature from mid-70s to mid-60s in the space of a day, it would pretty much guarantee death. If you drop the temperature just one or two degrees a day, they would probably be fine. As far as I know, the macro algae found we tend to keep (Ulva, Chaeto, Caulerpa) can be found in subtropical regions, if not temperate ones; then again, I am going off of photos here, and it is extremely difficult to differentiate between some of the species in these genuses; I may be mistaking tropical species for sub-tropical/temperate species.

Flow is another matter. Every species has different flow preferences, though I think most species in the same genus will have similar preferences. Anyways, some macros will be found in the intertidal zone (and adapted to crashing waves and turbulent conditions) whereas others are found on reefs or in mangroves, where flow is calmer and more laminar. You should research the species individually. The problem with no flow is that it will encourage detritus to get caught up in the macros and it will accumulate, eventually smother the algae, and rot and wreak havoc on your water chemistry. Also, low flow will decreases nutrient absorption rates.

That said, low flow and low temperatures will definitely discourage nutrient absorption. Low temperatures decrease metabolism and therefore growth. Low flow, like I said, discourages nutrient absorption, so it of course decreases growth as well. But you said they are going in a refugium, so low growth is a rather contradictory goal... I mean, to obtain low growth, you must have low nutrient absorption rates, but encouraging low nutrient absorption rates kind of defeats the purpose of having a refugium.

tl;dr - Low flow and temperatures will help you achieve your goal of survival with little-to-no growth. Low flow and temperatures will also cause low nutrient absorption rates, which is self-defeating and contradictory, since this is a refugium. Maybe you should reconsider your objectives?

I hope that answered your questions (or most of them, at least).

 

[andy01748]

Thanks for your responses. To be safe, I'll keep the temperature up and maintain some flow. Maybe I wasn't clear, but this is temporary isolation to protect them from inverts I am quarantining in my observation tank the macros were originally in. Once quarantine is over, the inverts go in my DT and I'll transfer the macros back.

 

[andy01748]

What type of caulerpa? The only type I've ever had eaten by anything was fern and it was a yellow tang eating it. As far as lighting most run between 12 and 24 hrs.A lot of diff opinions on it but I'd say 24 hr cycle. Also good flow helps, and I'd maintain a temp in the 70's to promote growth.

So far the emerald crabs are loving the caulerpa prolifera (which is a leafy variety). Can't tell if the pink coralline clusters have just been moved, or these are getting eaten. Wish the inverts would take a bigger interest in the green hair algae!