SPS brown out water change

[speedstar]

Wondering if anyone has ideas. I recently did a large water change about 30% on a 400g system. I tested Mg Alk and Ca and matched them to my current tank though Alk was .5 DKH higher due to IO salt mix.

The TDS of the water I used was at 1 before salt mixing, I mixed the salt and let it airate for about a week before I used it. Salinity was also a match. Well within a week of doing the water change, I noticed some corals browning out and it seems to have gotten worse. It is where the coral becomes that real ugly dark brown and has all polyps retracted.

I am wondering if some how garabge from an open window got into the water, perhaps a fertizier of some sort or pollen etc.

I still have some real great looking colors and on some i don't. Not sure If i should do another water change or what. I do not have a accurate PO4 test right now, but I placed a dead white skeleton into my tank and it quickly turned green.

I plan on adding some phosban tonight, but hoping if it swings parameters it doesn;t make it worse.

Anyone have any ideas comments or thoughts.

Thanks

 

[Amphiprion]

Do you do a water change of that magnitude on a frequent basis? If you suddenly do a water change quantity your tank isn't accustomed to, it is not uncommon for that to happen. One parameter you didn't list was the temperature. That can cause similar problems if they are too different.

 

[speedstar]

Temp didn't stray from 80 tank and WC water same. Even verified on the tank temp controller to be sure when i did the WC.

Nope I don;t do water changes often at all and am thinking maybe I shouldn;t do them at all. I've read some even some TOTM's run this way. The tank had gone 4 months without a WC and all was looking good. Just figured it would be best to do one to replace trace elements and the water had started to smell fishy if that makes sense.

Nothing had really changed or looked bad prior to the WC, it was basically wipe glass down every 3~4 days, other than that the tank sat there and worked no problems.

 

[jay24k]

I've done large water changes. Mainly I let the salt mix for about 4 hours prior and bring the temp up. Every 6 months, I do about 50 gallon water change on my 180. I've never had any browning issues. I've even had it where it was 3 degrees colder but after it mixes, it barely makes any difference. It is possible something got in your water.