Emergence of diatoms on sandbed

[BlueWorldJeff]

I have recently had the emergence of brown algae on my sandbed that has coincided with some other inconsistencies in my 180. All within the past month, I have had:

1. Emergence of Diatoms, mostly on sandbed. darker in some areas, non existent where there is no light (under rock/coral overhangs, near rock, etc)
2. Demise of Mandarin Goby. Had him for 2 years, never saw him eat, but he got big. Then past month started getting skinny and then disappeared. Haven't been able to find
3. Retraction of LPS coral polyps (hammer, torch).

Tank background: Moved from a 120 in sept 2016. New sand (seaflor special grade) 1-2", live rock migrated from 120, extra pillar added from dry rock 2 months ago (fully cured). Lights are 3 x Rapid LED Onyx, outside with 60 degree optics, middle with 100 degree. Apex ramps blues and mixed channels to 100% mid day for 4 hrs, whites to 60% max for 3 hrs mid day. Two Tunze 6105s provide flow, Skimmer is AquaMaxx Am250

Tank Maintenance: bi weekly 20-30g water changes with Instant Ocean salt. Vacuum of sandbed, clean skimmer, replace filter socks, clean glass

When I first started seeing issues, my parameters were:
SG - 1.025
NO3 - 2
PO4 - .17
Alk - 8.18
Ca - 380

I put 1/2 cup GFO in a TLF150 reactor at that point to lower phosphates.
Week later:
SG - 1.025
NO3 - 2
PO4 - .09
Alk - 8.56
Ca - 380

Lowered Alk drip.
Week later:
SG - 1.025
NO3 - 2
PO4 - .02
Alk - 8.29
Ca - 380

I did a water change on sunday and sandbed was perfectly white. I can already start to see the diatoms come back.

Some things I can think of:

• The DI resin in my RODI is almost expired, just the top 1/5 is blue still. TDS was 5 for past water change. Refreshing DI resin this weekend
• When I vacuum the sand, I still get clouds when digging into the sandbed. is this silicate being released? I am going to try to just get the surface of the sand bed vacuumed this next WC.
• With NO3 at 2 and PO4 now at .02, this should not be contributing to any algae outbreak. I will continue to feed on normal schedule (full cube mysis and full cube brine shrimp spirulina in morning, full cube mysis or spirulina and cube of cyclopods at night)

Anything I am missing? I also heard making lights more blue will kill diatoms.

 

[mcgyvr]

Only thing missing from your detailed post is an actual clear picture of what you assume is diatoms..

 

[BlueWorldJeff]

Only thing missing from your detailed post is an actual clear picture of what you assume is diatoms..

I'll get a picture once they rear their ugly heads again on my sand bed

 

[BlueWorldJeff]

One week after vacuuming sand bed with water change:

Phosphates have been lowered to around 0-.02. Glass is not dirty at all, I wouldve had to clean it by now with higher phosphates.

Still minimal polyp extension on LPS. GFO is still at a medium tumble

 

[mcgyvr]

Looks like you've got a bit of everything.. Cyano/diatoms/green film algae,etc..
Seems like the tank recycled and you are going through the uglies again.. very uglies..

I would
#1-get your RO/DI water back to 0TDS
#2-Stop messing with the sandbed (aka don't vacuum)
#3-Where are all the fish? Or what are you feeding so much for? Is that 4 cubes of food a day? I see one clown fish I think.. I'd expect 30+ fish for all that food
#4-Run red slime remover to get that cyano out..

But yeah.. That looks like crap.. Most certainly the sand.. Was it "live sand"? I wouldn't recommend that to anyone.. Dry sand is far better/cleaner,etc..

 

[BlueWorldJeff]

Looks like you've got a bit of everything.. Cyano/diatoms/green film algae,etc..
Seems like the tank recycled and you are going through the uglies again.. very uglies..

I would
#1-get your RO/DI water back to 0TDS
#2-Stop messing with the sandbed (aka don't vacuum)
#3-Where are all the fish? Or what are you feeding so much for? Is that 4 cubes of food a day? I see one clown fish I think.. I'd expect 30+ fish for all that food
#4-Run red slime remover to get that cyano out..

But yeah.. That looks like crap.. Most certainly the sand.. Was it "live sand"? I wouldn't recommend that to anyone.. Dry sand is far better/cleaner,etc..

1. Ordered a refill of DI resin
2. Will just vacuum up the algae on top of the sand bed, not digging in the sand
3. The following fish are in the system:
-Dejardini Sailfin Tang
-Blonde Naso Tang
-Yellow Eye Kole Tang
-Flame Angel
-Checkerboard Wrasse
-Leopard Wrasse
-Black & White Ocellaris Clownfish x 2
-Blue Chromis x 2
They definitely eat the majority of the food, I leave the pumps on during feeding, but not a lot goes over the overflow

4. I'll get the red slime remover

I'm guessing the tank recycle is because of digging in the sand. Is that also causing the LPS polyp retraction?

The sand was dry sand when the tank was set up. I rinsed it all until the water ran clear.

 

[Fnic99]

I have had a similar problem that seemed to start whe I began to vacuum the sand. I was assuming that vacuuming out organic waste was a good thing. Does anyone have some insight on this?

 

[mcgyvr]

I have had a similar problem that seemed to start whe I began to vacuum the sand. I was assuming that vacuuming out organic waste was a good thing. Does anyone have some insight on this?

A sand bed should not be disturbed as you are potentially removing/disturbing beneficial bacteria and micro-fauna,etc..

Even in a fairly shallow sand bed there are "low oxygen" (anaerobic) areas that form and if you are vacuuming the sand you are potentially removing those,etc..

Its one thing to just skim the top to remove stuff that has settled on it but to dig in/disturb it these problems can/will happen..

I NEVER touch my sand beds in any tank.. Let nature do its work...

I think vacuuming practices like that came from the freshwater world where you would have course gravel/stones and it was beneficial there.. But in a sand bed IMO... leave it alone..

 

[Fnic99]

You live and you learn. Thanks for the tip.

 

[BlueWorldJeff]

3. The following fish are in the system:
-Dejardini Sailfin Tang
-Blonde Naso Tang
-Yellow Eye Kole Tang
-Flame Angel
-Checkerboard Wrasse
-Leopard Wrasse
-Black & White Ocellaris Clownfish x 2
-Blue Chromis x 2
They definitely eat the majority of the food, I leave the pumps on during feeding, but not a lot goes over the overflow

Is it too much food for the livestock level?

I do one cube mysis and one cube spirulina brine dissolved and drained in a net and then fed from the net in the morning. At night I do one cube mysis or one cube spirulina brine shrimp and a cube of cyclopods dissolved in rodi and fed without draining.

 

[BlueWorldJeff]

Looks like you've got a bit of everything.. Cyano/diatoms/green film algae,etc..
Seems like the tank recycled and you are going through the uglies again.. very uglies..

I would
#1-get your RO/DI water back to 0TDS
#2-Stop messing with the sandbed (aka don't vacuum)
#3-Where are all the fish? Or what are you feeding so much for? Is that 4 cubes of food a day? I see one clown fish I think.. I'd expect 30+ fish for all that food
#4-Run red slime remover to get that cyano out..

But yeah.. That looks like crap.. Most certainly the sand.. Was it "live sand"? I wouldn't recommend that to anyone.. Dry sand is far better/cleaner,etc..

Its been about a month. I got my RODI to 0 TDS right away as well as stopped deep vacuuming the sand bed. I have done two water changes (Biweekly) and have just sucked the algae off the top of the sandbed. With GFO online, my PO4 got down to .02 in about a week and a half, but has come back to .08. I replaced the GFO to get it back down under .03.

I got a slide for my seneye to monitor ammonia and confirm my PH. ammonia was at .0001 and ph was high at 8.5. My alkalinity got up above 8 to 8.5 so I turned down the dose. My calcium was low at 380, so turned the dose up. nitrate is at 2 ppm. I still have the algae on the sand.

Is the high PH because of the algae and photosynthesis/CO2? or the high alk? I am thinking it would go down once I get my alk under 8, but if its because of the algae, then getting my PO4 low will help? I dont see any trace of ammonia due to the recycle of the bacteria.