[RobG]

Just ran the whole gamut of tests on my tank, and everything looks great to me , except: PO4. It measured 0.3mg/l

Where could it come from?

I tested my RODI water and it reads 0.

All I add as far as additives is Kent Liquid Calcium and Kent ProBuffer dKH

It must be one of these foods (I suspect the ones with ????):

Omega One Marine Flake (????)
Ocean Nutrition's Seaweed Selects
Sprung's Sea Veggies
Silversides
Frozen Brine (????)
Krill
Selcon
DT's
Golden Pearls

Anyone have any ideas?

I have no idea if the flake I'm using is any good. what should I use for a standard flake food?

Time for a big ol' water change...

Rob

[asmith]

My guess is that most of your phosphates are coming from the Golden Pearls. They are a great food, but are high in phosphates and will quickly cause problems if you overfeed. When I feed Golden Pearls, it is usually just a pinch or so twice a week in my 90 gallon reef.

HTH,
Andrew

[RobG]

Quite possible. I'd been feeding about 1/8-1/4 teaspoon of GPs about 3 times a week. I'll back that off to once or twice and see if it helps.

[srgtkoons]

The brine shrimp are also a source of po4 so watch how much of that you feed.

[RobG]

If brine are high in po4, what's a good replacement for them?

let me clarify, what's a good, inexpensive, readily available replacement?

[mastaJ]

I agree that it COULD be food...but otherwise if you are using a rubbermaid container i beieve that those COULD leak PO4 not all, just some of them...If you are using some type of container to store top-up/salt water i'd test the water coming out of there to see if...just maybe it could be that...just another idea that i thought of...

Otherwise you could cut back on food, OR...add some calurpa to suck up the PO4, or... HTH...

[RobG]

It's not the rubbermaid I'm using. I was using the regular old roughneck, but then read the thread from a little while ago that talked about it leaching PO4. I have since switched to the more expensive, food-grade Rubbermaid Brutes for water storage. I tested water that had been stored for over a week and it read 0.


Adding Caulerpa is probably a good idea for me. Got any species recommendations? I don't have a refug, so this would grow in the main, display tank. I had some "Feathery" caulerpa (don't know the species) a while back, but my yellow tang made short work of it.

Rob

[mastaJ]

hmmm....I'm pretty sure that any species of calurpa will get eaten by your tang, try some halimeada maybe someone else can suggest a good one...

[bongobrian]

Check out sawtooth caulerpa, also called razor or caulerpa serrulata. This stuff grows pretty slowly but your tang shouldn't touch it. I've had many species of caulerpa in my tank and my tang has eaten all of them except for the sawtooth. I havn't even seen him pick at it. I don't think the tangs bother the stuff.

[Joaco]

Before you try growing caulerpa macroalgae in your main tank just for phosphate removal (I wouldn't do it in the main tank), try this:

Drip your Kalkwasser in the skimmer's intake. Kalkwasser will precipitate the phosphate as calcium phosphate and it will be then removed by the skimmer.

This works EXCELLENT to remove phosphates.
BTW, credit for the tip goes to Dr. Ron Shimek

Joaco

[RobG]

I don't dose Kalk. I am currently using Kent Super Buffer dKH and Liquid Calcium.

Would I acheive the same effect dosing those near the skimmer intake?

Maybe a should add a hang-on refugium -- I don't really want to put any more pumps in the tank though -- already have 4 MJ 1200s and the pump for the skimmer...

Thanks for the good ideas...

[organicreefer]

im with joaco,drip kalk,and cut back on food inputs

[Randy Holmes-Farley]

Joaco:

Actually, it was Craig Bingman that published that limewater reduces phosphate, not Ron, though he may have passed it on. For that matter, Craig may have gotten the idea from someone else before running his tests, but it wasn't likely from Ron:

http://fpage1.ba.best.com/~cbingman/limephos.htm

However, whether it actually happens or not, and how it actually happens is open to discussion, IMO. Here's some writing phosphate, including the possible precipitation in limewater, that I posted a while back:

http://www.animalnetwork.com/fish/li...&RecordNo=2481