Help Replacing Sand Due to Phosphate Issue (Hair Algae)

igoblox

igoblox

Member
Hi, I have had my 30gal BioCube up for about 24 months. The first 9 months maintenance was performed regularly and everything was great. Coral thrived and water always tested near perfect.
Then I had to leave town for a year and left my tank only got water changes every 3 months and most likely was being overfed.
I returned home to a tank completely covered in long hair algae and most of my coral dead. This was about 3 months ago.
I scrubbed the rock free of all algae and did a big water change.
Then every 2 weeks done partial water changes and spot scrubbing.
My nitrates are testing 0 but I am still getting some phosphates levels detected and the hair algae keeps returning in spots every 2 weeks.
Mainly its coming from the sand bed, which I assume is the source of my phosphate issue.
I am skimming and have some activated carbon in the back chamber along with seachem phosguard.
The phosgaurd slows the algae but doesnt eliminate it.
I am to the point of almost rebooting the tank and starting over, but I would like to try replacing some or all of my sand first. Which may be like starting over in itself.

Any ideas on how to change out my sand or ideas to get the phosphates out of my sand bed.

Thanks in advance, this forum has always been a big help.
 
D

DaveK

Well-Known Member
What you do is siphon the old sandbed out, discarding the sand and any water removed. Then you replace it with new clean sand.

You should do this over several water changes. Don't try and do it all at once.
 
igoblox

igoblox

Member
Thanks for the reply DaveK!

So remove 1/4 of it, replace it with new live sand...wait a week or two-then remove another 1/4, replace with new live sand and so on?
 
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DaveK

Well-Known Member
That's it, although you might find that you can do it in thirds rather than quarters. It depends upon how good you are with the siphon.
 
igoblox

igoblox

Member
Well my siphon hose isn't very big (diameter), I was planning on siphoning some water/debris out and then scooping the sand out of the tank with a kids sand shovel or something.

Do you see anything wrong with that?

Thanks again for the help.
 
Last edited:
igoblox

igoblox

Member
The more thought I give this...the more concern I have for removing my entire sand bed.

Do you think that if I remove the top 1 inch of sand and layer it with an inch of new live sand, that I will eliminate some of my phosphate problem?
Then maybe dose some Red Sea NO3/PO4 X, to take care of whats left?

Whats the best course?
 
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DaveK

Well-Known Member
igoblox said:
... I was planning on siphoning some water/debris out and then scooping the sand out of the tank with a kids sand shovel or something.

Do you see anything wrong with that?

....
Click to expand...

This is exactly what you do not want to do. The whole idea of using a siphon is to remove the old sandbed along with all the garbage it's accumulated over the years. Digging the sandbed out releases all this bad stuff into the system. This is especially true if you see patches of black or dark substrata where anaerobic decay is going on. That's ok trapped in the sandbed, but you don't want to release it into the tank.

Get a larger siphon hose if you need to.
 
D

DaveK

Well-Known Member
igoblox said:
...
Do you think that if I remove the top 1 inch of sand and layer it with an inch of new live sand, that I will eliminate some of my phosphate problem?
...
Click to expand...

This is another incorrect thing to do, for the same reasons explained in my previous post. Removing that top inch exposes all the accumulated bad stuff to the system.

If you don't want to replace the entire sandbed, you can just replace part of it, but siphon out the sections you want to replace. For sections replaced go to the bottom.
 
igoblox

igoblox

Member
Understood.
That's exactly the info I needed, thanks Dave.

Also thanks for the link nanoreefing4fun.

You guys have been a big help.
 
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