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View Full Version : Controlling phosphates with macroalgae.


rt67ghy
01/09/2016, 02:34 AM
I'd like to start a discussion on phosphate control with only macroalgae. I'd first like to share my experience and then would like to hear other people's experiences on this topic.

First for some background information. I set up my tank (220 gallon DT + sump) in May 2014 and had a few small fish, a couple of nems, a couple of LPS corals and a few softies until June 2015 when I started slowly adding some more LPS corals. I didn't worry about nitrates (NO3) or phosphates (PO4) until January 2015 when I started using GFO after I found my PO4 to be 0.5 ppm with my new Hanna ULR phosphorus checker.

After that I tested PO4 every week and added GFO in a media reactor to control it. My goal was always to keep it around 0.1 ppm. I would add anywhere from 50g to 300g GFO once a week or every 2 weeks. With the increased feeding of my growing population of anemones and LPS corals (most of which I target feed) I found that from September 2015 I was adding 200g of GFO every week. I started regenerating the GFO to save on expenses.

I installed a DIY algae scrubber (not a very good one) in January 2015 and was harvesting around 90g of wet algae every 2 weeks. After some improvements to the scrubber I was able to increase the harvest to 160g every 2 weeks from December 2015.

I got 2 balls of chaeto in March 2015 and kept them in my fuge with cheap led lights where they were growing slowly and only once harvested some chaeto 8 months later. In December I added a 32 W CFL light to my fuge to increase chaeto growth. Also I noticed some strands of chaeto had escaped into the next chamber of my sump where I have my algae srubber and, more importantly, 3 X 24 W CFL lights for my scrubber.

The chaeto is now growing much better especially under the scrubber lights and I harvested 115g of chaeto yesterday from the 2 chambers. To my surprise I found that my PO4 has remained between 0.04 to 0.06 ppm for one month without the need of adding any GFO. Although not scientific, I have not decreased the amount of food I'm feeding to the tank every day.

Although it may be too early to tell, I believe I may be able to control my NO3 and PO4 with macroalgal growth. There is one more thing to add. From October 2015 I have been adding 5ml of Kent Marine's Iron and Manganese every alternate day to encourage phytoplankton growth to feed my gonioporas. These elements may be exhausted rapidly by micro and macroalgae and may limit their growth even if there is enough NO3 and PO4 in the water. It may be worthwhile to mention I only change 25% of my water once a month.

Harth23
01/09/2016, 01:10 PM
I just set up a 40 gallon fuge just for Marco growth so I would love to hear others thoughts as well because I'm pretty new. Any thoughts on really ramping up macro growth?

cvore2004
01/09/2016, 03:19 PM
I have a small amount of calerpa which I added to my fuge about 6 months ago to combat micro-algae. Since then my "green killing machine" has died, and still phosphates, nitrites, and nitrates are at 0, and I haven't seen hardly any micro algae growth despite probable overfeeding by my automatic feeder. (I'm rarely home more than every 3 days)

I'm very glad I got this stuff in my tank.

bertoni
01/09/2016, 10:24 PM
Macro algae can consume a lot of nutrients given enough light. The only issue with this approach is paying for the electricity, which might or might not be of interest. Of course, the scrubber or refugium requires some space, as well, but often that's not a problem.

cvore2004
01/09/2016, 11:55 PM
I got a set of leds with my used tank that are for planted freshwater tanks, so I just threw one in the fuge and it's been perfect so far, and only 36watts used.

rt67ghy
01/10/2016, 12:57 AM
I just set up a 40 gallon fuge just for Marco growth so I would love to hear others thoughts as well because I'm pretty new. Any thoughts on really ramping up macro growth?

A fuge that size should be great for macros. I first had red grape algae in my fuge which grew very big in my 20 gallon fuge before I changed to chaeto. My fuge also contains 3 anemones, a maroon clownfish and my media reactor so I have to limit the amount of chaeto I can grow in it. The next chamber to my fuge is better adapted for macro growth with 3 CFL lights hanging above it and I got 120 grams of chaeto growing there in one month from a few strands.

What type of macro are you planning on growing?

rt67ghy
01/10/2016, 01:31 AM
Macro algae can consume a lot of nutrients given enough light. The only issue with this approach is paying for the electricity, which might or might not be of interest. Of course, the scrubber or refugium requires some space, as well, but often that's not a problem.

Bertoni, I agree the electricity consumed is the main downside of this. Before my chaeto took off I was regenerating 2 cups of GFO twice a month which I found very laborious and risky with the acid and sodium hydroxide I was using. On top of that it took me a lot of time and I had to spend a lot on the NaOH and the GFO I bought to tackle my phosphates. Growing macro in a small sump/fuge to bring down PO4 to acceptable levels would be a challenge but luckily I built the largest sump (53 gallons) I could fit under my tank so space for me isn't an issue. The chamber after the fuge is 13 gallons and almost all the space is available for chaeto growth. I'm going to allow the chaeto here to grow unrestrained and harvest 50% each month. With the 3 lights I have here which I keep on for 18 hours a day for my scrubber I believe the chaeto may more than double in one month. I weigh my algae harvest and am keeping records so I can see the progress. If I can keep my PO4 low with macro growth I'll be able to increase the food I'm feeding my corals and anemones and not have to worry about GFO.

I think having the right amount of light is important. The more light you can provide the faster the growth you'll have in your macroalgae and the lower you can keep your PO4.

Harth23
01/10/2016, 08:04 AM
I would love to just grow Calerpa so I can feed it to the tangs in my tank. I have an 80 gallon fuge so the 40 gallons is just for Algee growth. But if I have to I can split it up so I grow cheto and Calerpa. Any special types you have had luck with? I have an LED light across that whole section so the lighting should be okay.

rt67ghy
01/10/2016, 11:59 AM
I only tried Halimeda Plant other than chaeto and it died within a couple of days. But it is slow growing so I think it wouldn't be ideal for nutrient export. The red grape algae I bought purely for ornamental purposes and I had no intention to use it to lower PO4. I've done a lot of research on the net and from everything I have read the fastest growing algae is chaeto so I'm planning on just sticking to this.

bertoni
01/10/2016, 07:01 PM
The grape Caulerpa seemed to grow the most strongly for me, if it's legal in your area. Chaetomorpha grows well, too, and is less invasive. Either might be fine.

Harth23
01/11/2016, 10:40 AM
I had person tell me this weekend that it is very hard to grow Calerpa and cheto in the same system because the cheto will outwork the Calerpa and kill it.

Dans85
01/11/2016, 11:11 AM
I had person tell me this weekend that it is very hard to grow Calerpa and cheto in the same system because the cheto will outwork the Calerpa and kill it.

I experienced the exact opposite. I had about equal parts of both in my small fuge, and within a a few weeks the capulera had over doubled in size and the cheato had almost died off completely.

jason2459
01/11/2016, 11:16 AM
I experienced the exact opposite. I had about equal parts of both in my small fuge, and within a a few weeks the capulera had over doubled in size and the cheato had almost died off completely.

Same here. I had grape calurpa and ulva. Both did well and I had little growth and even die off from chaeto with those two in the refugium.

Darth_Tater
01/11/2016, 11:35 AM
This is more of an assumption from a new reefer than a scientific observation, but be careful not to harvest too much of your macro or it can throw the whole system out of whack. I believe that's how my very impressive hair algae farm got started. Everything was going good and Chaeto was growing like crazy, then all of a sudden after I harvested a large amount I had an algae farm in the display and fuge and the Chaeto barely grows at all now. I don't think it can compete with the microalgae once the micro is established. Either that or phosphate didn't start leaching from my dry rock until 6+ months after I started the tank.

Also, I started with Chaetomorpha and Grape Caulerpa and the Chaeto came out the clear victor.

yacn
01/11/2016, 11:40 AM
I can't seem to grow calerpa...it always goes sexual on me and dies. I don't have time to watch and clip it when it does this...since my sump/fuge is in basement. Chaeto is only thing I've been able to grow consistantly...and lately not much growth at all. It used to grow like crazy.

I had to change my lighting and ever since I changed my lighting I don't get much growth. I had inexpensive coralife dual T5 light with one 10k and one actinic bulb, it had plastic cover that kept moisture from getting into bulb area (didn't work well) and wire bracket on the sides to hang over tank, but I kept getting shocked...tried several new replacement lights of the same brand since I got great growth results, but each time after a couple of months would get shocked. So I decided to get rid of this light. I'm not sure if they make this model anymore. I would get enought chaeto I would trade back to LFS for credit.

I've tried different kinds of regular screw type flood lights from Home Depot after reading people had success with them and a LFS used them too w/ success....tried grow lights of this type too. I also tried several brands/types of CFL self ballasted screw type bulbs in an old 10 gallon light fixture that has 2 sockets. LFS sold me CFL bulbs that were 6000K spectrum. I'm currently using 20 watt coralife mini 50/50 and have also tried their 20 watt colormax....using 2 bulbs at a time in fixture...but no growth.

When I buy a couple of large softball sized clumps of chaeto it dies.....I can only sustain about one fistful size ball of chaeto in my fuge

I wanted to switch to economical LED for fuge to see if that would work better...open to suggestions. any other reasons why I am experiencing this.

tmz
01/11/2016, 02:05 PM
Caulerpa out did chaeto ,IME. Ulva proved invasive and difficult to eradicate from display tanks. If well lit and spacious enough macro algae can control PO4 and nitrogen excess. It also provides extra photosytnetic activity which uses up some CO2 and adds some oxygen. Algae does produce organic exudates though,some of which are toxic; so organic export mechanisms like GAC and skimming are helpful. Dosing a little extra iron to the algae fuge can help it grow.

In my case I ultimately abandoned my algae refugia and ats efforts in favor of culturing heterotrophic bacteria via vodka and vinegar dosing. This keeps PO4 in the 0.02ppm to 0.04ppm range per hanah 713 and NO3 around 0.2ppm per Salifert test. I wanted to use both methods but the alge just couldn't grow in competition with the bacteria.

yacn
01/11/2016, 07:36 PM
i forgot to mention I leave light on in fuge 24/7

MidwesternTexan
01/11/2016, 07:52 PM
Chaeto lights should not be on 24/7, they can be yes

I used to have Massive amounts of chaeto- always grew well under CFL's for me.
I'd always trade it to my lfs, and/or give away- gallon zip locks at a time!

I was listening to a MACNA download- forgot who- who said the ration of Nitrate to phosphate removal for chaeto was ~ 16:1- in other words, not that great on phos.

Fast forward to about 5 month ago-
now using my own DIY- large surface area- ATS!!
Months ago I gave all my chaeto away- things havene't looked this good-
nuisance algae all but gone everywhere since!!

IIWY- I'd nix the chaeto and go with the ATS- IMHEO

Reef on!

bertoni
01/11/2016, 08:24 PM
Most algae likely can grow with light 24 hours a day as long as the lighting is not too intense. I'd target more like 8 or so and see whether that's enough.

Buzz1329
01/11/2016, 09:22 PM
Bertoni, I agree the electricity consumed is the main downside of this. Before my chaeto took off I was regenerating 2 cups of GFO twice a month which I found very laborious and risky with the acid and sodium hydroxide I was using. On top of that it took me a lot of time and I had to spend a lot on the NaOH and the GFO I bought to tackle my phosphates. Growing macro in a small sump/fuge to bring down PO4 to acceptable levels would be a challenge but luckily I built the largest sump (53 gallons) I could fit under my tank so space for me isn't an issue. The chamber after the fuge is 13 gallons and almost all the space is available for chaeto growth. I'm going to allow the chaeto here to grow unrestrained and harvest 50% each month. With the 3 lights I have here which I keep on for 18 hours a day for my scrubber I believe the chaeto may more than double in one month. I weigh my algae harvest and am keeping records so I can see the progress. If I can keep my PO4 low with macro growth I'll be able to increase the food I'm feeding my corals and anemones and not have to worry about GFO.

I think having the right amount of light is important. The more light you can provide the faster the growth you'll have in your macroalgae and the lower you can keep your PO4.

Very interesting. Are you running a skimmer in your sump or is it all macro?

Thanks,

Mike

tmz
01/12/2016, 12:54 AM
I prefer a dark period 16 hours on. The N to P intake varies from species to species and to some extent is based on the levels in the water. 16: 1 is the the Redfield ratio, an enmasse measure of ocean phytoplankton which gave a ratio of 116 C(carbon); 16 N( nitrogen) to 1(phosphorus). Point is most of the food you are adding is likely close to that ratio ; so most algae should help reduce both phosphate and nitrogen proportionately.

yacn
01/12/2016, 07:23 AM
I am running skimmer in sump. LFS told me to run light 24/7 and that they didn't need dark periods of time. He also mentioned it will help w/ my PH when my main tank lights go off at night

tmz
01/12/2016, 09:57 AM
Whether algae needs a dark period or not is debateable; they get one in nature. 16 hours on including the lights off period works for me.

outy
01/12/2016, 02:39 PM
Whether algae needs a dark period or not is debateable; they get one in nature. 16 hours on including the lights off period works for me.

Not only that the opposite cycle if the fuge is large enough, can offset the PH swing at night.


My problem with chaeto, is that it sucks up the Nitrate and phos out of the water quickly and after 3 weeks of rapid growth it then stops growing altogether.

Dosing iron now to see if I can kickstart it up again.

bertoni
01/12/2016, 10:26 PM
Well, when I was talking to a scientist working at a company growing micro algae commercially, his opinion was that most algae likely could grow 24 hours a day if the light was not too intense. I don't know whether that's optimal, but it should be possible.

jason2459
01/12/2016, 10:33 PM
I remember, maybe an article or some posts, back when I was growing macro in my refugium that it was recommended to give at least 4 hours of dark time for them to "breath" or something like that. Seemed to make since to me but I have no idea how accurate that is or even if it was right.

My ATS is on a 20 hour light schedule now and I know several people running their ATS 24hours. I'm going to try that out soon.

bertoni
01/12/2016, 10:44 PM
I would leave a dark period, as well, although I would be more concerned with the various small animals that can grow in a refugium.

jason2459
01/12/2016, 10:51 PM
I would leave a dark period, as well, although I would be more concerned with the various small animals that can grow in a refugium.


Now a days my sump is almost always completely dark minus a tiny bit of red glow coming from a drain pipe from my ATS. I bought it from Turbo Aquatics mainly because it's designed specifically to keep as much light in the ATS "box" where the screen is. My sump critters seem to like the almost eternal darkness better.

rt67ghy
01/13/2016, 12:27 AM
Very interesting. Are you running a skimmer in your sump or is it all macro?

Thanks,

Mike

Yes, I'm running 2 undersize skimmers (because the height under my DT doesn't allow for one big one). I'm still getting a good amount of skimmate in both skimmers so I'm not planning to take those off-line soon. Also, I believe that the skimmers may take out some chemicals released by some corals which would otherwise harm my other corals if not taken care of. I'm not sure if macroalgae would remove all the harmful chemicals.

rt67ghy
01/13/2016, 01:10 AM
Do algae need a dark period?

This is a very relevant question since it can affect macroalgae growth. I remember from my high school biology lessons that plants need a dark period for growth.

Trying not to get too technical, Light reactions need light to produce organic energy molecules (ATP and NADPH).

Dark reactions make use of these organic energy molecules (ATP and NADPH). This reaction cycle is also called Calvin Cycle. ATP provides the energy, while NADPH provides the electrons required to fix the CO2(carbon dioxide) into carbohydrates.

Although algae are not plants, the phosynthetic process in them is the same, so it appears that algae do need a dark period for building their cells.

I leave my ATS lights on 18 hours a day (Floyd in the threads on algae scrubbers recommends keeping the lights on for 18 hours). and my fuge lights on for 8 hours. I have found that the chaeto under my ATS lighting grows much better than the chaeto in my fuge which makes sense. I can always increase the photo period in my fuge depending on how much I want to reduce PO4 and how fast.

bertoni
01/13/2016, 08:04 PM
As far as I can tell, they are called "dark reactions" because they can occur without light, not because they must happen in the dark. Lots of people run refugia with 24-hour light cycles and have at least reasonable growth. Searching for "Calvin Benson cycle" will turn up a lot of hits.

rt67ghy
01/14/2016, 12:53 AM
Bertoni thanks for pointing this out. After I made the last post I realized that maybe the Calvin reaction happens in spite of the darkness and darkness is not actually a requirement for the reaction to take place. So, this means we can increase our algae growth if we choose to by keeping the lights on 24/7. I may try this as an experiment to see how much algae yield I get. Very interesting for those (like me) who have high nitrates and have been battling high PO4 for a year. Thanks again, I really appreciate it. To make further progress in this hobby, we need to get rid of misconceptions.

bertoni
01/14/2016, 04:44 PM
You're welcome. Biology is very complicated. We all have more to learn.