Recently see some tip burns. Tried a few things but maybe just tried too many things... For some reason, as of right now I am still uncertain of the actual cause, tips of the sps started to bleach and algae started growing on it. The usual suspects:
1) Parameters off?
2) Too close to light?
3) Flow too high?
4) Insufficient nutrients (Nitrate and Phosphate)?
This is the piece in question. Apologies for the poor photo, the damn Anthias just wouldn't stay away.
But this was just the beginning. So to answer my own questions. I did a battery of tests over the next few days and the results were as follows on 12th Jan @ 23:22hrs
Alk - 6.5
Calc - 410
Mag - 1280
Phos - 0.04 (Started feeding alot more about 2 days before, it normally is at 0 to 0.01)
Nitrate - 5 (Started dosing SEACHEM Flourish Nitrate night before as it was at 0)
Salinity - 1.026
I figured if I have another colony that was higher than this one, directly in the path of my flow then it should not be the lights or the flow. So my best guess is that it is due to the previously consistently extremely low to undetectable nitrate and phosphate. So on the 12th of Jan at the time I figured maybe I should try acropower. Apparently it works for people who keep ULNS systems, though I wouldn't classify my system as ULNS. I feed twice a day via auto feeder, 1 cube of frozen mysis in the evening, Easybooster in the morning and evening, 1/4 tsp of reef roids broadcast over the tank in the evening.
On a side note, I typically keep my Alk at 7 but I have learnt something valuable. If you note my Alk on the 12th is at 6.5, the reason for the drop is due to changing out my GFO. I did not know that GFO strips alk from the system as well. Typically I'd only fill half my reactor with GFO but that day for some reason I decided to fill the reactor full. So immediately the alk dropped to 6.2 and I had to dose additional alk and brought it back up to 6.5, since then I have slowly increased my alk to where it is today at 7.2. So the tip issues I'm seeing could also be because of that alk swing that day. But the other sps didn't show such issues.
Back to Acropower, on 16th Jan I got my hands on acropower, based on the instructions and the size of my tank it seems like I should be adding about 40ml of acropower weekly or even daily. So I went with the weekly option and spread it over a course of week, 5ml's a day adding up to 35ml over 7 days. Fairly safe I thought. First day 16th Jan added 5ml acropower, 2nd day 17th Jan added 5ml acropower. A few hours later I realized something seemed to be wrong with the tank. One of my monti had started fading to grey and only a handful of polyps could be seen. I have the same monti at 2 different places in my tank and both reacted the same way. Could it be the acropower? Not sure... Decided to try dose an additional 5ml the following day 18th Jan and monitor further. On the 19th the monti seriously looked like crap. Completely grey and almost no polyps could be seen. Panic mode started to set in. Plan of attack. Stop dosing. WC first.
Spent the next 36 hours doing WC, in total changed up about 20 to 25% water. Thankfully by the night of the 20th Jan after the water change was completed the monti looked alot happier. By the morning of the 21st all the polyps came back, the body still greyish but the colors are starting to darken and come back slowly.
Sent out an ICP test after the WC, realized I made a mistake because I should have sent it out BEFORE the WC. Oh well... Panic brain problems...
Last night I decided to just dose 1ml of acropower only. Observe the corals and see how they react. If no negatives I will probably proceed to dose 1ml per day and monitor accordingly. I have observed some good whenever I dose the acropower, the PE on the sps seriously extends. Hoping that it will work out well as I have seen many videos of amazing growth of sps when using acropower.
Wishing all of you a Happy and Prosperous Lunar New Year!