Fluval 13.5 Evo AIO Reef- Algae problems and Aptasia HELP


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Nov 22, 2020
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Cross-posting from Fishlore as I hadn't yet discovered this forum when I posted there :D I hope that's alright...

I run a Fluval 13.5 Evo AIO. The tank gets weekly 20% (3.5 gallon) water changes, I use Instant Ocean Reef Crystals, and a Nicrew HyperReef 50W light set at 80% blue and 5% white on a 10 hour light period. The tank runs at 70F and is about 3 months old. I also use an RO Buddie with a DI resin as a water source (runs 0-5 TDS).

Stocking is as follows;
- 2 occelaris clowns
- 1 fire shrimp
- 1 cleaner shrimp
- 1 blue tuxedo urchin
- 1 pink turban snail
- 1 blue legged hermit
- MAYBE 1 tiger pistol shrimp (haven't seen him in nearly 2 months and the fire shrimp moved into the cave I thought he was in)

- 5 zoa colonies
- 1 paly colony
- 1 xenia colony
- 1 red knobbly mushroom
- 1 acan echinata
- 1 acan lord
- 1 GSP colony
- 1 green frogspawn
- 1 indo-orange frogspawn

Parameters (post WC)
Salinity: 1.027
Temp: 70 F (usual temp)
Ammonia: 0
Nitrites: 0
Nitrates: 0
dkH: 10.6
Calcium: 430 ppm
Magnesium: 1560
Phosphates: Unknown, appeared to be zero on a inaccurate liquid test
Note: until the algae bloom I was running at about 10 nitrates so yes the tank is cycled

In the last 2-3 weeks I've hit the ugly phase, and knowing that free floating algae just re-anchors elsewhere I haven't been worrying about the front glass being covered in algae until WC day. This past WC day, I cleared off the front glass and what I "uncovered" was shocking.

One of my zoa colonies has aptasia on it. There is hair algae everywhere including on frags to the point it's smothering zoas. One of my zoas actually looks bleached in a place it had previously been growing new heads. My GSP looked more algae then polyp and my green frogspawn doesn't seem to open anymore. My xenia isn't extending, I actually removed it's plug since it was just drowned in hair algae. I also have sea lettuce growing EVERYWHERE; all over my rock scape, the back glass, frag plugs, just everywhere.

I'm not sure where to go from here. I've had some suggestions of an emerald crab, vibrant, microbacter clean, purigen, chemi-pure blue, vodka dosing... I just really don't know how to move forward from here and any advice would be helpful!


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Nov 22, 2020
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do you have pictures? it would help to see the tank.
also i would check how much you are feeding and check RO as it could be causing problems.

I feed Vitalis soft pellets every 2-3 days. My RODI runs below 5 TDS (usually 0, but bucket contamination sometimes brings me up to 5).

Do you have reef tank aspirations and visions?

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