LPS Health Help. This is such a frustrating hobby!

[Psychedelic Fins]

Tank is 4-1/2 months old. 180 gallon system with 6 fish - 2 tangs (yellow and Kole), 2 clowns, lawnmower blenny, and a melanaurus wrasse. Fish look great. Coraline algae is growing well on the dry rock in the tank. But.....added some zoas and euphyllia in the tank and none are thriving. Color is good, but no extension on the euphyllia. Zoas are a mixed bag. Two are doing well, two are doing okay, and two just look ticked off (closed tubes). Lighting is six t5s (three blues, 2 coral plus, 1 actinic). At first I thought the corals were getting too much light, so I scaled that back to just 8 hours a day (with majority blues on) and placed all corals on tank bottom. No change in coral health. Scaled down flow to low flow. No change in coral health. It has been three weeks with no improvement.

After more research, the advice was phosphate needed to be increased. Red sea testing at 0 consistently for entirety of tank life. Other parameters staying pretty consistent:
Alk 8.5
Calc 420
Mag 1400
Nitrate 4-8 ppm
Salinity 1.0255
pH 8.2

The plan was to raise the phosphates in the tank. Stopped skimming a week ago, began adding phytoplankton daily, removed filter socks, fed benepets reef food 3x per week. A reddish purple web has started covering the sand in places (see picture) in the last 2-3 days and is getting thicker. My thought was that this was probably due to my low nutrients and consistent with my thoughts about the phosphates.

My Hanna checker arrived today and tested phosphate at .05 and .07 thirty minutes apart. Red sea test kit still has phosphate at 0 (taken in between the two hanna readings). Not sure which result to believe. I was planning to start dosing phosphate, but now I'm not sure if that is the best course of action. The goal was to raise the phosphate to the .03-.05 range while keeping nitrate in the 5-10 range.

I am going to re-test phosphates in the morning and do a 30 gallon water change while vacuuming the sand. After that, I'm not sure what to do.

Which test kit would you believe? What would your next move be?

 

[DaneGer21]

The red cyano could be from wacky unstable parameters and now when you slowed down your flow it has taken hold.

How high are your lights mounted? Ever checked par?

What do you use for flow? (return pump, and power heads)

...just kicking around some random thoughts here

 

[Psychedelic Fins]

The red cyano could be from wacky unstable parameters and now when you slowed down your flow it has taken hold.

How high are your lights mounted? Ever checked par?

What do you use for flow? (return pump, and power heads)

...just kicking around some random thoughts here

Lights are 8" above tank in canopy. Haven't checked par. My LFS said their par meter was calibrated for LED, not t5.

Flow is a 1200 gph return pump split into four returns in all corners of the tank. In addition, two ice cap gyre 2k on short ends flowing toward the middle of the tank. I dialed both the lights and the flow back (gyres set to less than 40%) to help (it didn't) the euphyllia. I can always dial them back up, as I think I can rule that out as the cause of the unhappy corals.

Any thoughts on which test, Hanna or Red Sea, you would believe. I added phyto this morning (8 hours ago), so it might be effecting the phosphate test. I will test again in the morning prior to my water change and before adding phyto to try and get a better test. Neither the Red Sea or Hanna tests are difficult, so I don't think user error is in play, but something is wacky with the differing phosphate results.

 

[DaneGer21]

Lights are 8" above tank in canopy. Haven't checked par. My LFS said their par meter was calibrated for LED, not t5.

Flow is a 1200 gph return pump split into four returns in all corners of the tank. In addition, two ice cap gyre 2k on short ends flowing toward the middle of the tank. I dialed both the lights and the flow back (gyres set to less than 40%) to help (it didn't) the euphyllia. I can always dial them back up, as I think I can rule that out as the cause of the unhappy corals.

Any thoughts on which test, Hanna or Red Sea, you would believe. I added phyto this morning (8 hours ago), so it might be effecting the phosphate test. I will test again in the morning prior to my water change and before adding phyto to try and get a better test. Neither the Red Sea or Hanna tests are difficult, so I don't think user error is in play, but something is wacky with the differing phosphate results.

As for the phosphate results, I would say depending on the individual tests, they could be within their own respectable error margins.

I would look into what their error margins are, then decide in your opinion which to trust. Is it a visual result decided by you? Or a test that use optics/lights(I’m sure there’s a real term haha) and gives a result for you.

Testing such a low range I’m sure is difficult anyways, so it’s hard to say.

I will say, I have never used a Red Sea(not because I believe they’re bad), but, it’s because I choose from the start to get a digital tester, so, I do own a Hanna.