Nori = Phosphates = Hair Algae?

[Bill S]

As some of you know, I'm battling a pesky hair algae problem - and not winning - in my 215. Not really losing, but not winning. I've recently added:

A tuxedo urchin
A rabbit fish
300 hermit crabs
500 cerith snails

None of these SEEM to be taking care of the problem.

My phosphates have creeped up a little, and I do have a phosban reactor, but not set up (need some phosban). I also need a new PO4 test kit. Hopefully Jeremy has those...

Anyway, yesterday, just for the heck of it, I tore off a piece of nori (from the bulk nori many of us have bought), and put it in a quart of water. The piece was about 1/8 of a half sheet. I feed a half sheet every day. I removed the nori, without squeezing it, after it had soaked for a while.

I then tested the water. Here's a caveat: the test kit is a crappy old one. 2 ppm of phosphate. So, if I do the math: a half sheet would yield 4 ppm in a gallon. Over a week, that's 28 ppm in a gallon, or about .1 ppm in my 270 gallon system in a week!

Anyway, I'll update this after getting a new kit, and retesting this with a full sheet in a gallon. BUT, I'm thinking that I'm going to start soaking my nori before feeding...

[greenmako]

wow good find I will try to replicate the process to see if I get the same numbers

[RICKY81]

what is a nori, what is it used for, and were do u put it.

[C.Mydas]

nori is seaweed. food for algae eaters. If you have a tang and you want it to be healthy you MUST feed nori. Most of us put it on a plastic clip or tie it to a rock and drop it in the tank.

HTHs

[captexas]

Interesting find. I was actually starting to wonder about that as I recently started using some nori I got at Wal-Mart instead of the expensive packs from the LFS. I've had a weird algae bloom and/or cyano pop up over the past month or so. I thought it might be my halide lighting so I've had it turned off for the past two weeks, only running VHO's. Most of the cyano looking junk has gone away, but there is still some so I'm kind of at a loss as well. I was wanting to try a phophate reactor, but haven't gotten around to setting one up.

[Bill S]

Well, B & B didn't have the Salifert PO4 kit... So, I guess I'm still testing wth an Aquarium Pharm kit, that's years old and probably not worth a dang.

[greenmako]

ok here are my readings:

I used both salifert and Milwaukee Martini Laboratory low range phosphate meter.

Base readings I took with just my tank water, both salifert and the Milwaukee unit tested at zero
http://greenmako.smugmug.com/photos/262450674_LsJEy-M.jpg

Next I took tank water and soaked a half sheet of the Nori we just bought until it was completly soaked.
http://greenmako.smugmug.com/photos/262450681_XecXi-M.jpg
http://greenmako.smugmug.com/photos/262450686_s4r8E-M.jpg

Next I took out the nori and used that water for my tests.

The Milwaukee unit only reads from 0 to 2.50mg/L if the water it is reading is over the limit it flashes 2.50 and thats exactly what it did. So it was over the limit of my test.
http://greenmako.smugmug.com/photos/262450692_JHqFA-M.jpg

Salifert kits measures in ppm so I wanted to convert the mg/l to ppm.
standard density of saltwater at 70degrees and a salinity of 1.025(same as my tank) is 1.028

so ppm = 2.50/1.028 = 2.43ppm's roughly so you could assume the 2.50mg/l is about the same as 2.43ppm's

Salifert only read up to 3ppm and when I tested the nori water it was solid blue so it could be way over 3ppm or just at 3ppm or 3.1ppm I just don't have a test kit for high range values.
http://greenmako.smugmug.com/photos/262450668_EGWAK-M.jpg

My tank's phospate levels don't seem to be affected by it but it seems like it could add a lot of phosphate over time

[captexas]

Wow, great work! :thumbs_up: Definately makes me think twice about how much I feed my fish. They tend to tear it in pieces and some of it ends up getting stuck in my Hydor Koralias. After awhile it looks pretty nasty as it breaks down.

I'd be interested to see what the results would be for other foods as well, both frozen and flake. I feed Formula One flake and even though it says "Low Phosphorus", you really don't know what their definition of "low" means. Sounds like a good investigative project for someone into research work. The flake would be rather easy to test as long as you use a standard measured amount each time and allow it to soak for a set amount of time to simulate the time it is in the tank during feeding. With frozen I would wonder if the results would vary based on how long the food had been allowed to soak/break-down in fresh water. I tend to mix about a weeks worth of frozen food at a time in freshwater and keep it in the refridgerator.

[greenmako]

I might just do that it sounds like a fun project

[Bill S]

Brian,

Try doing this test with a smaller sample. Like I said above, I used about 1/8 of a half sheet.

[greenmako]

ok I'll try it with an 1/8th right now

[greenmako]

ok I tested an 1/8th of a sheet.

I also read on my test kit that iron in levels higher than 50mg/l mess up the reading so I looked on the back of the nori and it has 2% based on 8 mg a day so I measured out a liter of my tank water and measured how much iron was in an 1/8th of a sheet and it was way under the 50mg/l so I knew it shouldn't mess up the reading this time and it may have been messing up the reading before b/c of the small amount of water I was using.



1/8th of a sheet came out to: .37mg/l which means a whole sheet would be: 2.96 mg/l
or 2.88ppm in one liter of water

[Bill S]

Quick calculations, late, show your numbers will yield between .1 and .2 ppm over a week, for 1 sheet per day, in a 215 gallon system...

[greenmako]

I feed on average 2 sheets a day which would be 5.92mg/liter
my total water volume is: 1287liters roughly
so my calculations unless I'm wrong lol would be a net dilution of 0.0046 mg a day to my tank

[Bill S]

So, your calculation is around what mine is...

"roughly" 1287 liters? How rough a calculation IS that?

[greenmako]

So, your calculation is around what mine is...

"roughly" 1287 liters? How rough a calculation IS that?

tank is 300gallons, sump is 80gallons, skimmer holds 8gallons reactor and other equipment some where about 8 gallons or so then I tried to guess how much my coral and rock work displaced.

[villjr]

Very informative thread. At one time I had a huge hair algae problem when I was feeding Nori and had tangs. Never thought the Nori may have contributed to it.

[BA]

So, your calculation is around what mine is...

"roughly" 1287 liters? How rough a calculation IS that?

haha i laughed when i read that, i was thinking...uhh "rough estimation?"

[RICKY81]

so, i guess i'm a day behind, but i was reading the discussion and it really is very informative, and so about the nori i had already bought some seaweed at Petco, but didn't know that that's what it was. and i used a whole sheet in my 75gal tank. i had a yellow and scopas tang, and powder brown tang and fed them the sheet about 3 days later, my wet/dry was smelling horable like "feces" so had to clean everything out, then started to grow alot of green stuff on my glass, and then about 2 weeks later my yellow and scopas tang died.... so in other words too much nori could have killed my fish. my coral is doing fine, just noticed that my bubble anemone has not really opened up that well... by the way my lights are i believe Orbitz 516w (2-150w mh.. 4-54w T-5 HO) and i have also left my lights off for an entire day. but i guess i'll just leave the mh lights off...... just wanted to put some imput.

[greenmako]

so, i guess i'm a day behind, but i was reading the discussion and it really is very informative, and so about the nori i had already bought some seaweed at Petco, but didn't know that that's what it was. and i used a whole sheet in my 75gal tank. i had a yellow and scopas tang, and powder brown tang and fed them the sheet about 3 days later, my wet/dry was smelling horable like "feces" so had to clean everything out, then started to grow alot of green stuff on my glass, and then about 2 weeks later my yellow and scopas tang died.... so in other words too much nori could have killed my fish. my coral is doing fine, just noticed that my bubble anemone has not really opened up that well... by the way my lights are i believe Orbitz 516w (2-150w mh.. 4-54w T-5 HO) and i have also left my lights off for an entire day. but i guess i'll just leave the mh lights off...... just wanted to put some imput.

4 tangs in a 75 gallon is a little too many tangs and I doubt that the nori did anything to kill your fish and if you didn't feed the nori they might have died faster.
Don't stop feeding nori b/c of this, tangs need the nutrition.

[cpreefguy]

Interesting! Brian, where can I find that PO4 meter? Do you like it?

[greenmako]

Interesting! Brian, where can I find that PO4 meter? Do you like it?

works really good, I bought that unit off of ebay

[Bill S]

After running phosban AND now soaking my nori, my PO4 is down quite a bit, in just 24 hours...

And, I agree with Brian. Just the feeding of nori wouldn't make a difference.

[Jamie]

Thanks for all the great info guys! So if we soak the Nori....we won't have as much of a Phosphate problem? Seems easy enough.

[second_decimal]

interesting thread. thanks for sharing :-)

[Henny]

Great Info! I'm having a problem with green algae growing on everything in my tank right now and I was wondering what could be causing it but I never that it could be the seaweed I was feeding. It's not Nori but it's the dried type from the LFS. Thanks for Sharing!