Tips on "un-sanding"?

[elensius]

Though I love having a nice 4-5 inch sand bed in my tank that I would love to keep, I have gotten to a point where I just can't seem to keep my phosphate down to the level it needs to be at for corals to grow... and I'm blaming the sand bed (I'm guessing it is "saturated" and thus just keeps leaching phosphate into the water, no matter what I do to try to lower the levels?).

However, I vaguely remember reading somewhere that it is a bad to just take all the sand out all at once... so I'm hoping that some of the experts in our club can offer tips on the best way to go about it (as well as let me know whether my thoughts above might NOT be the source of my problem - I freely admit I'm not an expert on the possible "routes of chemistry" the phosphate might be taking in my tank).

Thanks for any input you can share!

-Nate

 

[zeroinverse]

Nate: reason not to stir up a deep sandbed all at once is due to releasing large amounts of sulphates into the water column. (the rotten egg smell). It is toxic to animals in high concentrations.

It is a by-product of ammonia/nitrate/nitrite reduction process when there is lack of oxygen (as occurs in lower levels of deep sandbed).

Of course you may release other chemicals also.

You can use a siphon to "suck" it out, but expect to have a lot of replacement salt water available to topoff.

You could breakdown tank and "upgrade" in process. Hahahaha!

Have you just tried water changes to keep phosphate down? Do you have sand-stirrers (gobies, starfish, nassaurius snails, etc).

 

[northbay-reefer]

You definitely don't want to take all the sands out at once. You can do it gradualy but I would leave about 1-2" of sand. Under your rock work is where most of the phosphate and nitrate are coming from so I reccommend a smaller foot print where your rocks works are sitting.

Personally I always have a bag of new sand on hand and I replace about 1/4 of the sand every 6 months or so.

 

[elensius]

Thanks for the tip(s)...

Around 6 months ago, when I was getting a fair amount of algae growth in my tank even though my phosphate kit was giving readings of 0 (or very very close to it), I decided something was amiss... so I bought a new kit and discovered that my phosphate levels were actually *through the roof* (hence the algae, persistent lack of coral growth compared to what I always see in other people's tanks, and even "mysterious" die offs of various pieces from time to time).

Via water changes and GFO, I have got the levels down to about .1-.15 mg/L using a Salifert test kit, but I can't seem to get it any lower than that no matter how frequently I do water changes/replace the GFO... and so I'm blaming the sand (of which there IS plenty of it "hiding under rockwork," Tom ).

Anyhow, that's my story... thanks for the advice so far (and any more that may come in!).

 

[leveldrummer]

you can gently syphon a little out as you do waterchanges, shouldnt hurt anything like that, becareful as you remove the sand out from around the base of the rocks, they could tumble and shift and crack the bottom glass.

if you keep runnign the GFO and doing water changes. eventualy the phos will leach back out of the sand and you can reverse the whole process. it may take a while though.

 

[Grant W]

When I removed my DSB I just remved about 1/4" at a time as I was doing water changes until I was down to about an inch and a half and then did a lot of gravel vaccing doing only about 15-20 percent at a time.