Reading PO4 Accurately?

[goose0211]

Is it possible to read PO4 in the tank water accurately?

I don't mean are the test kits accurate, I mean that if you have algae growth, are the readings you take accurate as I'd always assumed that the phosphates were being consumed by the algae to help them grow - if so then how do you get an accurate reading to help maintain a good level?

I'm getting some algae growth on the rocks and nitrates are reading about 3 -4 but phosphates are showing at 0 so finding it difficult to know how to balance the PO4 and Nitrates

Thanks

 

[taricha]

PO4 test in the water is an accurate reflection of the PO4 concentration in the water.
Algae may have sources of local P that are available in much higher concentration than what's in the water.
For example, GHA in my tank sometimes gets bits of fish flake embedded in it. Cyano mats may exploit local P in the sandbed.

So water po4 concentration may not tell the whole story.

 

[92Miata]

PO4 test in the water is an accurate reflection of the PO4 concentration in the water.
Algae may have sources of local P that are available in much higher concentration than what's in the water.
For example, GHA in my tank sometimes gets bits of fish flake embedded in it. Cyano mats may exploit local P in the sandbed.

So water po4 concentration may not tell the whole story.

This also means that if you have low P04 in the water, PO4 in the water column is not driving your algae, and trying to remove P from the water column is not going to be an effective means of controlling algae. (but can be an effective means of killing your corals)

"You can't measure PO4 in the water because your algae is eating it too fast. Algae means you have high phosphate" is one of the reefisms that bothers me the most.

 

[elysics]

If you have algae growth, you don't have enough cleaning crew.

A balanced tank always has algae growing, they are just eaten as fast as they grow. If you stop algae from growing by starving them, you kill the rest of your tank as well.

 

[goose0211]

Thanks all, it sounds like I can rely on the po4 readings as what is actually there.
Makes me wonder how to work out what is feeding the algae I have…

 

[elysics]

Thanks all, it sounds like I can rely on the po4 readings as what is actually there.
Makes me wonder how to work out what is feeding the algae I have…

Well the food is. What you measure is how much nutrients are leftover after everything has taken its share, that's not the same as the nutrient throughput, i.e. how much is in the food and additives that you throw in the tank.

Some high growth systems filled to the brim with coral have massive amounts of nutrients thrown in, but everything is eaten up so nothing is left in the water.

If algae grow and nothing eats them, they can pull the values in the water to zero despite growing because they account for almost all of the throughput. But that doesn't mean you should feed less, the actual nutrients left in the water for the corals are still low and they will starve.

What you need to do is to manually remove algae so the issue doesn't cascade, and at the same time add cleaning crew that eats the algae and excretes the nutrients sequestered in the algae back into the water, for your corals to eat.

For a not so nice metaphor, think about plastic trash. If people just use plastic all the time and nothing is done, there are mountains of trash everywhere, and that's ugly. Now we could put less plastic in circulation, but that's going to make people (the corals in the metaphor) unhappy because they wouldn't have useless trinkets to play with. What we can do instead is have garbage collection so the trash goes somewhere else and the streets aren't ugly anymore (manual algae removal) or recycling the plastic into new useless trinkets (cleaning crew eating the algae and relieving themselves into the water) , so the garbage mountains are put back into circulation for people to play with the garbage and it's a cycle rather than just endless growth of the garbage mountains.

What you can measure with your test kit is how much plastic garbage the people currently play with, not how much they buy and throw away onto piles.

Thats just supposed to explain the issue, not be a statement about what I think we should actually do about the plastic problem lol

 

[Spare time]

If you have algae growth, you don't have enough cleaning crew.

A balanced tank always has algae growing, they are just eaten as fast as they grow. If you stop algae from growing by starving them, you kill the rest of your tank as well.

THIS ^^^^^^

Reef tanks are designed to grow algae...... that live inside corals. If you can't grow algae outside corals, you can't grow algae inside corals.