Getting all scientifical with PO4?

[Twizted1]

I have not been very open about this but, I have a major problem with GHA in my tank. I have at time had it cut way back. But it just gets worse. I have tried gfo, added more clean up crew and I do large weekly waater changes. I have done this all winter. The more I try the worse it gets. So I have been thinking of what to do. Because I am considering tearing the tank down and getting rid of it. But I don't really want to do that. Anyways, I was thinking about PO4 & its sources. I feed nori. So I did a little experiment. I took 2 quarts of fresh water. tested it for PO4. Came back with 0 PO4. Took an unmeasured piece of nori. Soaked it in 1 quart of wat for 30 min & tested it. Results where off the chart. I also feed seaweed I buy @ my local Kroger. Ran the same test with the same results. I kknow that algae feeds on PO4. I never thought it would release that must back into the water tho. I need to figure something out. Any thoughts?

[chromiumlux]

Wow, I never thought about Nori leaching PO4 into the tank. I know a lot of flake and pellet foods will leach small amounts. I feed a 1/4 sheet every day. I wonder if soaking it first would help? Are you running GFO and carbon?

[Twizted1]

No just gfo. But I not using it in a reactor, which I know is not using it to the full. Reactor for both gfo & carbon are in the works. I hope to have them both up & going by months end. I also have been meaning to ungrade my return pump. Thant to will need to be done soon. When I do my water change I spend a couple of hours plucking this stuff out & syphoning off everything I can.

[Ashlar]

Well, there are radical ways to lower PO4, but they're right at the edge of the hobby.

The first one that comes to mind is using lanthanum chloride. It's sold in pool stores (SeaKlear) or via sites like marinedepot.com (Blue Life Phosphate Rx).

You mix a small amount of this into RO, then drip it into a filter sock in your sump where you're putting tank water- the lanthanum chloride immediately binds to phosphates creating a lanthanum phosphate dust that the 5 micron filter sock catches.

The other radical solution to lowering phosphates is only applicable if you have a very good nitrate reduction / export mechanism. In tanks with aggressive skimming / DSB or refugium / carbon dosing / biopellets, you can get to the point where you have 0 nitrates but high phosphates. Some have dosed calcium nitrate to actually bring nitrates up, so that bacteria and other organisms can consume the nitrate + phosphate.

But realistically, I'd start with just cutting back food (including nori) and see how that goes.

Any detectable nitrates?

[Wall_Tank]

I have the exact opposite problem.   Higher Nitrates, and almost no Phosphates.   I've thought about increasing a phosphate source to allow for better nitrate reduction.   I've been able to get my Nitrates down to about 5.   Not any lower.

[Ashlar]

I have the exact opposite problem.   Higher Nitrates, and almost no Phosphates.   I've thought about increasing a phosphate source to allow for better nitrate reduction.   I've been able to get my Nitrates down to about 5.   Not any lower.

How about a 'DSB in a bucket'?

Fill a 5g bucket 3/4 full of sand, and pop in a couple of uniseals. Plumb it in to your system, and forget about it. If it ever gets stinky, just take it offline, dump the sand and start over.

[Wall_Tank]

I have that, it stays dark......the water flow keeps any detritus from building up on the surface.  My nitrates were closer to 25, put on a BioPellet reactor, and was able to pull things down to 5.......I'm not sure if I cannot go lower due to no phosphates or I just need a little bigger reactor.

Even before I added all of that, I have never been able to grow macro algea in my sump......no phosphates to feed on.

[Ashlar]

Dang!

Realistically though, 5ppm of nitrates is a lot better than 0.5ppm of phosphate. I'm not sure I'd even consider it worth tinkering with, if you don't have cyano and/or GHA everywhere.

[Twizted1]

Phosphates read .08 ppm. I have not tested trates in a while. I will do that right now.

[Twizted1]

NO3 = 0
I think I thought one time some where that you could have a problem with Po4 & NO3 and you would still get a 0 reading on the tests. Something like the algae consumes it as fast as it's greated?

[Neogenesis]

NO3 = 0
I think I thought one time some where that you could have a problem with Po4 & NO3 and you would still get a 0 reading on the tests. Something like the algae consumes it as fast as it's greated?

That would be my tank.  My tests read 0, however things are starting to look a little green.  No algae outbreaks yet, but I've been large water changes, and I need to put new filters in my RO system.

[Boonjob]

yes, you most likely are balanced.. something is consuming the NO3 that is being produced... but because not enough NO3 is being produced; you see the excesses of p04 that can't be removed by your macro as they are linked the macro needs both.(in a nut shell)

[Wall_Tank]

Dang!

Realistically though, 5ppm of nitrates is a lot better than 0.5ppm of phosphate. I'm not sure I'd even consider it worth tinkering with, if you don't have cyano and/or GHA everywhere.

Ya I know.   Phosphates are 0-0.02     I know there are some phosphates in the tank, there is some cyano in my frag tank on the sand bed.   There is a little green algea in my main tank, but the tangs keep that well in check.   

[Ashlar]

Ya I know.   Phosphates are 0-0.02     I know there are some phosphates in the tank, there is some cyano in my frag tank on the sand bed.   There is a little green algea in my main tank, but the tangs keep that well in check.

0.02 isn't *perfect* but anything under 0.03 is acceptable in my book. As long as things are being kept in check, and things are growing well, sounds like you've got a balance that you can live with.

[Ashlar]

NO3 = 0
I think I thought one time some where that you could have a problem with Po4 & NO3 and you would still get a 0 reading on the tests. Something like the algae consumes it as fast as it's greated?

Yup, sounds like you're in equilibrium, where something takes it up as soon as it hits the water. In your case, it's not what you want (GHA) taking it up.

Something as simple as a couple days of lights out might stunt the GHA long enough for other micro-organisms to catch up. Or just running some GFO.

I don't know that I'd go for a nuclear option just yet.

[Twizted1]

Yup, sounds like you're in equilibrium, where something takes it up as soon as it hits the water. In your case, it's not what you want (GHA) taking it up.

Something as simple as a couple days of lights out might stunt the GHA long enough for other micro-organisms to catch up. Or just running some GFO.

I don't know that I'd go for a nuclear option just yet.

I have gone a day with lights out. And have reduced the lighting period a little. I heard raising Mg would help kill GHA also. So I have been very slowly raising it. I just added a buch of snails from the swap. I am going to order a bunch of tiny crabs also. So I will keep fighting it. For now.

[Ashlar]

Well, raising Mg has worked for a lot of people fighting bryopsis (and Kent Mg seems to be the key to that one). I hadn't heard the same for GHA, but it might work on the same principle.

Snails and crabs also add to the bioload, so I wouldn't go overboard. They poop, too. Crabs are especially good if you tend to overfeed, since they home in on any leftover food.

Maybe try 48 hours of lights out?

[METZCOOL]

I have some lantham chloride and have used in my tank with great results, pm me if you are interested in trying it.