Wat is this grey patch on sand?

[itchyhand]

Observe that my DSB got a patch of greyish. Bubbles can be seen on it. Anyone know wat it is?

I've attached a pic.

[itchyhand]

Observe that my DSB got a patch of greyish. Bubbles can be seen on it. Anyone know wat it is?

I've attached a pic.

Here is another.

[weileong]

Cyano aka "Red carpet ", welcome to the club.

[Rex Ng]

use rowa phos

[Kelmen]

Or get cleaner critters that sift sand bed. Like hermit.

[itchyhand]

use rowa phos

I got use rowa. Just use it for abt 1 mth now. Bought the container that can treat up to 1000litres of saltwater. Divided quantity to 3 parts cos my tank 3x2x2. Total abt 300 litres of water. But still got.

I've already scoope up tat portion after I posted this thread. Till today, not seen it coming back ...yet.

If I already use rowa, how come it still happens?

[itchyhand]

Or get cleaner critters that sift sand bed. Like hermit.

Just using a star fish sand shifter. Hardworking chap.... but somehow keep avoiding tat patch.

Heard from a LFS owner, the seio pump cannot direct downwards, MUST direct at the surface. I've been directing it at the middle of my tank(meaning the middle of the length & height). Was I wrong?

[hotlemond]

wat about nitrate?

[itchyhand]

wat about nitrate?

My nitrate is abt 25ppm. using tetra. Been changing water but still the same nitrate level. Someone in forum said tetra always give high nitrate reading

If view from the sides of the tank, u can see bubbles trapped in the DSB. I presume they are nitrogen.