Hammer coral unhappy and high phosphates.

[Uzair Aiman]

Hi. I have a 27gallon AIO tank. My inhabitants are a pair of clownfish and a 6 line wrasse. A frag of GSP and a wall hammer coral. For the past 1-2 weeks my wall hammer coral has been quite unhappy and has closed/shrinked up. Maybe tissue recession.

At first I didnt know the cause of it so I expected I just had high nitrates/phosphates. The coral started to get unhappy during a diatom bloom. Now the diatoms start to settle down and Im facing some green algae.

After realising the diatom bloom, I suspected high nitrates and phosphates causing this.

After running water tests today I found that my phosphates were high.
These are my parameters (I also just did a 20% water change)

Salinity :1.025
Ammonia : 0
Nitrite : 0
Nitrate : 0
Alkalinity : 8.0
Phosphate : 0.5-1.0

and these are my filtration system :

A filter floss
Seachems carbon matrix
Seachems Purigen
Seachems Phosguard
Bubble magus QQ protein skimmer
Some bio media balls

I just bought the phosphate tester so I wasnt confident about the colour and tests but it was a range between 0.5-1.0ppm which is very high.
Im not sure if this helps but this is the colour.

After getting those results I just felt that my numbers were kind of odd. 0 Nitrates but sky rocket phosphates.
Any Idea how I can get the phosphates to go down? And does it mean that this high phosphate be the cause of my sad wall hammer coral?

 

[P-Dub]

Sorry to hear about your issues with the hammer. Since you are battling diatoms and GHA and looking at the rockwork begs the question how long has the tank been cycled?

 

[Uzair Aiman]

Sorry to hear about your issues with the hammer. Since you are battling diatoms and GHA and looking at the rockwork begs the question how long has the tank been cycled?

This tank cycled for 1 months++. I did a fishless cycle with a dead shrimp and microbacter7. I monitored all the ammonia and nitrite in the process. My first fish were the clown pair. The tank was set up on the 2nd of may and I added fish at 16th June.

 

[P-Dub]

Tell us about your lighting, tank depth, coral placement, and source water and top-off methodology.

 

[Uzair Aiman]

Tell us about your lighting, tank depth, coral placement, and source water and top-off methodology.

I use an aqua knight spectra. My tank is around 35cm deep and the coral is placed on/near the sand bed.

I use RODI water and top off manually every 2-3 days...