Sps sudden pigment loss

[Best Fish-Jake]

I never hit post last night so this is behind a few posts but ....

The why is unknowable if you haven't been tracking. If Alk drops too low growth will stop, when you do a water change (do you do regular changes?) params come back up and growth may pick back up until Alk drops too low again. Something like that. More luck than anything else. How long have you had the slimer?

Water changes used to be biweekly. buuut no nutrients in the tank so they were neglected for a while.. I’m now dialing them back in 10% weekly until I see my color come back, then 15% biweekly after that.

I got the slimer 13 months ago

Yesterday (it’s probably had ~ 8” fragged off by now)

 

[Mattrg02]

Don’t worry so much about dosing nutrients, just measure twice and use quality test kits. Also, consider it supplemental dosing rather than as the main source. I upped my feedings until I could get by with only an occasional need to dose nutrients.

 

[markalot]

Water changes used to be biweekly. buuut no nutrients in the tank so they were neglected for a while.. I’m now dialing them back in 10% weekly until I see my color come back, then 15% biweekly after that.

I got the slimer 13 months ago
Yesterday (it’s probably had ~ 8” fragged off by now)

So your tank will improve doing more water changes but it still won't be all it can be. The water changes will raise the Alk high enough for the SPS to start growing, which they will but then once Alk is depleted they will stop. Water changes are doing nothing for nutrient removal, 15% biweekly is replenishing trace elements and some Alk and that's about it. This is a good thing, that's what water changes in an SPS are good for, replenishing traces.

Get yourself some two part and start dosing BUT as you've proven here, even by accident, acros and other SPS can tolerate low Alk much better than high Alk so be cautious not to dose too much. Target 7KH and if it rises past 7.5 KH stop dosing and start again with a much smaller dose. If this tank was healthy and growing I would say to stop dosing for a day, measure the Alk decline, and use a reef calculator to figure out the daily dose.