LPS corals not looking happy

MizunoEnigma · Dec 26, 2023

I run a RedSea 200 G2 with all of their accessories minus the microdoser. My tank has been running for about 7 months now but I haven't been testing vigilantly until October which is when I ordered my Hana Checkers. When I got my parameters within range and stable, the existing corals in my tank starting to look really healthy, full, and extended. However in the past 1.5 weeks, I have noticed a marked and progressive decreased in polyp extension and fullness in most of my LPS (bubble coral, hammers, frog spawn, octospawn, goni and duncan) but my torch corals and blastos have been looking okay. My softies also have been looking fine except for the only mushroom I have. I made the mistake of changing too many things during a small time period so I don't know which change triggered this event.

Changes in the past 2 weeks:

Added a 3lb piece of dry rock to the back of my tank to mount my zoa frags
Changed my reef mat roll
Cleaned my sump pump
Cleaned my protein skimmer
Change my light settings (not intentionally, the light unsynched from the app and I needed to re-pair it to the app and it wiped the lighting program it was previously running)
Dosed reef roids twice a week from once a week
Performed about x3 10% water changes (a response to how my corals looked, my pH was 8.5 and my phos was 27ppb)

Current Parameters:

Salinity	34.7 ppt
Temp	25.5 C
Alk	8.6
pH	8.3
Calcium	483ppm
Magnesium	Not Tested. (Don't have checker for that but I use Instant Ocean's Reef Crystal and mix half cup of salt per gallon of RODI so it should be ~1345ppm)
Phos	6ppb
Nitrate	6.4ppm

I don't why but I was previously struggling with low alkalinity but high pH. Any reason that could have triggered the changes?

Thank you in advance for taking the time to read my post!

CasperOe · Dec 27, 2023

Hello there- and welcome to R2R!

Could you share some pictures of your corrals; mainly the ones you say don't do too well? Take them under white light, please.

There's nothing about your parameters that seem out of order.

You have, as you state done a number of things at the same time although the only think I can see that may have had some sort of impact would be the rocks and the change in your lighting schedule.

I would invest in a test kit for magnesium (.. not the Hanna as it is useless!) just to verify this one. Some of my euphyllia corals were struggling because if low magnesium. I raised it slowly to about 1400 and tank is looking more happy now.