PO4 in SB

[Du]

Hi.

I have no any significant algae activity in my nano tank, my corals and fish are ok. I just wanted to try to verify po4 in my sand.
By taking the syringe i soaked up the water from bottom of SB.

Result: Po4 1-0.5 ppm in sand :eek1:

Result from tank water are 0-0.1 of po4.

Any comments? Is this are normal? Is my sand (1 year old) are phosphate capacitor? Is the BB are key for no Po4...?

 

[Randy Holmes-Farley]

It is certainly possible for there to be substantial phosphate in the pore water of the sand. Organics that make their way down into the sand are broken down by bacteria, and some of the released phosphate may stay there.

Also, there may be a lot of bacteria in the water. All of the phosphate in them may show upon your test. Likewise, certain calcium or magnesium phosphate solids may show up in a phosphate test if it becomes acidified in testing.

Is the BB are key for no Po4...?

The fact that the phosphate is in the pore water and not in the water column suggests otherwise.

The BB vs sand issue is a complicated one. If you otherwise remove organics that would get deposited into the sand, and if some of the phosphate from those organics make their way back to the water column (likely), then removing the sand might help reduce phosphate. But if those organics just settle out elsewhere, then there is no net advantage.

 

[Du]

Thanks, Randy

<a href=showthread.php?s=&postid=6830099#post6830099 target=_blank>Originally posted</a> by Randy Holmes-Farley

Is the BB are key for no Po4...?

The fact that the phosphate is in the pore water and not in the water column suggests otherwise.

Yes But it will not available for manual removing (GFO, siphon or so out) it will not bioavailable for microorganisms in tank (phytoplankton, macroalgae that can help with nitrates, and so), it will be just waste. May be i wrong, but this po4 no making sense for me. I will remove my sand as soon as possible.

 

[Randy Holmes-Farley]

What are you hoping such a removal will change in the main tank, if you do not have an algae or phosphate problem in the tank water?

 

[Du]

I think i will have problem in the future, when the sand will contain 2-4 ppm PO4 it will release in water and will drive algae activity...imho. You think not?

 

[Randy Holmes-Farley]

I don't know. I have sand that was in the tank for many years, and I didn't have a problem. I suspect that if you have adequate export, that 'extra' import may not matter. However, if you have inadequate export, then maybe it will.

 

[Du]

I don't know adequate export in my tank or not...I hoped what SSB in tank and DSB in samp will make this export, but imho didn't do it. I have PO4 enough to make the problems to me.
10 liters if sand contain 10 mg PO4, so in my tank it will be 10\100L = 0.1 ppm. Too much imho
I want to compare it with BB method
Thanks.

 

[boxfishpooalot]

Randy,

I had a crazy thought. Sand exists only as a means to grind dirt particles into dissolved stuff, that corals and other life can use. True?

In the ocean the sand is moving from day to day and from currents that hit it in different directions, makes the sand tumble and fold. The top layer gets exchanged with the bottom layer due to the way waves move(in circles) Our sandbeds mostly sit there and do nothing. What do you think of my theory? Am I nuts !

 

[Du]

<a href=showthread.php?s=&postid=6845705#post6845705 target=_blank>Originally posted</a> by boxfishpooalot
...Our sandbeds mostly sit there and do nothing. What do you think of my theory? Am I nuts !

:thumbsup:

 

[Randy Holmes-Farley]

Sand exists only as a means to grind dirt particles into dissolved stuff, that corals and other life can use. True?

In my tank, anyway, I don't think there is much grinding going on.

I want to compare it with BB method

Let us know how things change.

 

[Du]

In my tank, anyway, I don't think there is much grinding going on.

With all respect.

It means, what you have another dirt export, before it go in sand.
So yours sand also do nothing No?
Sorry

Let us know how things change.

Yes, but i need one more year

 

[Randy Holmes-Farley]

So yours sand also do nothing No?

I don't claim the sand does anything useful in my tank, but I also don't think it does any especially detrimental.

 

[Du]

I don't claim the sand does anything useful in my tank, but I also don't think it does any especially detrimental.

Yes, i'm thinking also

Thanks.

 

[boxfishpooalot]

Randy, from my experience:

With a sand bed 1 year ago, with the same fish as today nitrates were always 5ppm or less. The sand bed was only 2-3" deep. I had no refugium at that time. Eventually I added the fuge and light, noticeing not much a change.

Then when I thought that a bare bottom tank would be the soloution to everything, I was surprised that even with a clean tank the nitrates would not drop below 30ppm, eventually getting to 100+ppm from sugar addtions(I suspect)

Even with my 400 watt halide in the fuge in a bb tank with chaeto, grape caulerpa and some red caulerpa, the nitrates got that high. So I conclude:

Yes I do think that sand acts as an effecient export of nitrate, but perhaps not phoshpate. Plants are needed here when the bacteria push phosphate near the top layers,the plants can grab that existing phosphates. Also, proper water movement is important to move the sand, keeping less ditritus out of it. But not just strait flow patterns, random water movement.To prevent dead spots where hydrogen sulphide will accumulate . Also wave turbulence, much like a wavebox provides to bring the bottom layer of sand up to the top by rolling. Much how you see sand ripples on the beach water.