Removing DSB with heavy Hydrogen Sulfide Blackness.

[RockyHeap]

Help Anthony or others experienced in removing long established Deep sand beds and accumlated nutrients.

my tank is 135 gallon, set up almost 10 years. Fine aragonite sand was used 3" deep on one half of the 6 foot long tank. So, 3 foot long x 3" deep of sand is covering a zero current plenum.

Reef is mostly soft corals and zoo's, a couple brains and pociliapora, couple anemones, and over 200 pounds of LR. I run a ton of current in the tank, but nutrients have accumulated over the years.

So, how best to remove this blackened sand? My thoughts are to set up a temporary 55 gallon tank next to the 135, filling of the 55 with established tank water, and transfer over any loose and easily movable corals. Keep up water circulation and heating of this 55 tank for 24-48 hours.

Break down reef structure in the 135 and remove all LR to another temp tank/holding area (rubbermaid container) and syphon out the blackened sand, then remove the plenum after trying to syphon out detritus from under the under gravel filter through one of the 1" ports while using a powerhead to positive pressure blow water through another 1" port in the UGF. Don't want all this gunk to circulate in the main tank.

Allow main 135 reef to settle all stirred up detritus and do massive waterchange before putting main show corals back in. 24-48 hours later?

Should I run Carbon, Phosguard/ban, and filter sock/foam mechanical filtertration during this process?

See the pics for how bad the sand is, this isn't Cyano or other bacteria, I'm going to syphon a cup or two of sand into a bucket to measure the hydrogen sulfide stink factor.

HELP! Suggestions on the lowest impact to the reef and valued critters?

I plan to go bare bottom or just an inch of sand in the future.

 

[Herefishyfishy]

Most of what you are looking at is algae on the glass. Doesn't mean that there isn't a lot of build up in the sand. Syphon with a large diameter hose and toss. Do only part at a time and prepare for small re-cycles. After the rock has taken over for the sand's bio-load filtration, can do bigger changes of the system. Baby footsteps are always best. Nothing good ever happens fast in a reef.

 

[dnjan]

I agree that I think you are seeing a combination of algae and dinoflagaellates against the glass rather than blackened sand. Next time you siphon, use a tube around 1/2" inside diameter to siphon a spot right next to the glass. Go all the way down. You will probably see relatively clean sand fill in around your siphon hose.

Assuming you still want to get rid of the sand, follow the directions in the previous post.

 

[MikeS]

I agree as well. I was shocked at how clean the sand in my 5 year old DSB was when I removed it.

MikeS

 

[Anthony Calfo]

indeed the algae next to the glass commonly gets all types of algae in time.

You would had to have obscenely neglected your DSB to get it that black anywhere else (from anoxic conditions) let along throughout.

Its simple enough to test: take a rigid plastic tube (undergravel filter tube from the LFS... 3' stock lengtsh in 1", 1/2" etc)

Use it like a pippette and cap the top with your thumb, insert it into the tank and into the sand bed and then release your thumb (evac the air) then cap it again to pull up sand samples. If its black in the middle fo the sand bed... stop after the first sample

The age of your sand bed is not a reason/factor alone for changing it. I have seen 16 year old beds moved that looked and smelled as clean as the day they were set up (literally). I still have a DSB from my first greenhouse (one of the later culture tanks). Its a 12 year old bed and is not polluted by any stretch of the imagination.

 

[RockyHeap]

thanks all, (hello again Anthony, I met you in seattle a couple times)

yes the stink factor of my sand was low or non existant.

some of my corals are showing stress, so I was thinking sand bed.

thanks all again. The black algae has only showed up the last year. guess its on the glass edge.