Phosphate in food
 

Seeing as how P04 levels in our tanks seems to keep creeping up, I tried a test yesterday to see how much is in the food that we are feeding the inhabitants in our tanks.

I took a single 7 1/2 x 8" , 2.8 gram piece of nori and placed it in 1 liter of RO/DI for 24 hours at room temperature and tested the water before and after.

Before P04 was 0.0 ppm.
After P04 was 1.0 ppm.

The only nutrient export systems that I am using are protein skimming and water changes, which are not enough as I am seeing more cyano growth and small patches of hair algae appearing.
I would like to get some macro algaes growing, but my sump and main tank have large algae eating fish in them, most of which are being transferred to a new system soon.
I'm looking forward to seeing if planting some macros will work to take up the P04 fast enough to compensate.
I measured my tank water and it showed 0.5 ppm P04 before the water changes that I am now doing.
I'm going to do the same test with some frozen mysis, rinsed and unrinsed next.

edit:
18 grams (about a tablespoon) of Piscine mysis, unrinsed, showed about 2.0 ppm in the same test. :eek:

edit:
18 grams of frozen mysis, thawed then rinsed briefly in R/O brought the weight down to 14 grams. P04 was a little over 1.0 ppm.

Mitch

Very ... illuminating. 1.0ppm from one sheet of nori is impressive.

Stop feeding nori! :biggrin: As much.

Yes I'm serious.
I have stopped feeding my whole sheet of nori every day and have cut back to 1/2 sheet every 4 to 5 days.

This has been a big change for my huge algae eating population, but, they are all still very fat and have been for the 2 months I have been doing this.

Just a thought.

What are they eating instead, Jonathan?

Mitch

Good question - another question I have is, would it be safe to multiply liters and get the likely effects a sheet of nori (unconsumed) would have on 100 gallons of water?

Also, could you do the same test in some tank water, Mitch? I know, I know... :biggrin:

I'm sure someone could come up with some sort of math equation for P04 in ..P04 out. :mrgreen:
Do you want new tank water or old, Alan?
I've only commandeered one measuring container from the kitchen for now, I'd be pushing it for another.. :mrgreen: , and right now it's got mysis in it... :smile:

Mitch

It would be simple multiplication, if the relationship is the same per volume of water. It may behave differently when immersed in a bath-tub full of RO, for instance (or not)...

And I guess new tank water, thanks. :biggrin:

If you need containers, I've been squirrelling away a couple... if my wife sees me use anything for the tank, she now sets it aside as "not fit for human use" - and it becomes fishroom property. :mrgreen:

I don't think it's a good idea to leave unconsumed nori in a tank for more than a couple hours, and never have.

I wouldn't ever cut back on what my fish consume however.

Do a water change.... :rolleyes:

So how much do you put in at a time, and how long then does it take for your horde to finish it off?

LOL Alan, it takes them about a half hour to consume a 2 x 4.

1-2 flake feedings, one frozen feeding, and sometimes a pellet feeding.