Dosing Phosphate to my Reef

[Red Firefish]

Hi everyone. My refugium is attached to my reef tank, sitting next to it, and I grow several ornamental algae species there to produce a nice aesthetic. I find that the algae that I keep (Ochtodes sp., Halymenia sp., Codium sp., Meristiella sp., Dictyota sp. and other reds) are consuming phosphate much more rapidly than nitrate.

To maximize plant growth, I've been dosing it with Seachem's phosphorus additive. It is "derived" from potassium phosphate, but I don't really know what all is in it besides the breakdown of macronutrient percentages listed on the bottle.

Product details here:
http://www.seachem.com/products/prod...hosphorus.html

My fellow reef geeks think I'm crazy to dose phosphates into my reef tank, but if I don't, I notice cyanobacteria begin to bloom on the sand in the display. I imagine this is due to surplus nitrogen and organics that aren't being taken up in a phosphorous-limited system.

Does anyone else dose phosphorous to their plant tanks, and if so what are you using?

Is there an industrial use for potassium phosphate that might make it easier to purchase in bulk (I'm imagining something similar to magnesium chloride)?

Thanks everyone!

[Plantbrain]

You might want to consider some of the past threads here on the topic.
You likely already have

Anyway, SeaChem PO4 is nothing but KH2PO4 in water............


Mixing Dry Chemicals for Seachem’s Dosing

Dosing - Add 62.2 grams or 11.125 tsp of KNO3 to 500 mL of distilled water for Flourish Nitrogen Substitute

Add 3.5 grams or 3/4 tsp of KH2PO4 to 500 mL of distilled water for Flourish Phosphorus Substitute

So if you want to pay for water and nice bottle, you may..........or you can buy KNO3, KH2PO4 for peanuts on line, or some use Fleet enema, which is sodium phosphate mostly.

I think 2-4$ ought to get you 1 pound of KH2PO4. perhaps a life time supply.

Also, adding PO4 will drop the NO3 down pretty fast, depends on the feeding/food types etc, load in the main tank etc.

I'm a bit leary telling SPS folks to use macros, but the softies might use it if they are willing to risk experimentation in a specific tank for it.

I know macros alone well, but not adding the other layers of critters to the system. I'm slowly getting there, but things done well are best done slow.

BGA's are good at very low levels, much lower than macros, when there is an influx of organic N or P, they tend to do pretty well, so do most small noxious algae.

Same for Aquatic FW plants and micro algae dynamics.

Might be clued into organic N ->NH4 production.............

Macros normally would take up the NH4 rapidly as bacteria mow down the Organic N and release the NH4.

If the macro algae are limited suddenly by say PO4 or Fe or whatever limiting nutrient etc..then they are not going to take up the NH4..........

This tells the noxious algae spores that it's a great time grow...........because whoever is there, ain't doing much/well etc ands that there's a nice supply or N around thus less competition for limited resources and a good chance to complete a life cycle.

If it's from an organic source...chances are...........there's more rotting macros, corals, some source ........on the way.

So even if it's a small amount.they can bloom.

Meanwhile folks are just looking at the down stream stuff, PO4, or NO3, seeing what happens long after the intial step occured that induced the noxious algae.

Then they blame NO3.

Yet there is a lot of correlation between Organic N- NH4 and noxious algae. Take that a step farther, add NH4.
Then observe.

In FW systems, we get noxious algae with high light(not that much with lower light and the effects take longer time frames).

So we can reasonably say that NH4 and organic N can induce noxious algae, thus suggest at least one cause.

I would suspect the same here.
It makes an excellent model to signal a spore to grow that matches our observations.

I can add NO3, not get the algae.
I can add PO4, and not get the typical algae, just diatom blooms from hell.

So something else is causing it besides those two.
You need a good healthy reference control tank to test such things.

If you cannot do that, then you really cannot say what effect the treatments have, it might be for other confounding issues/things/methods/overlooked parameters etc.

But if you cannot induce an alga with the reference system, and cannot several times.........then that treatment alone cannot be a cause.

Falsification.................

Regards,
tom Barr

[oblongshrimp]

This is where i buy my ferts for my fw planted tank.....

http://www.bestaquariumregulator.com/ferts.html