Tank crashing for no reason, need help!

[MadTownFess]

I did a 25% water change. All pumps/magnets are less than 15 months old, I took a quick look and everything seemed fine. Any other suggestions?

 

[ScottB]

Well your stated parameters are pretty ideal and I imagine your test kits are all less than 16 mos old too.

Are your PO4 and NO3 numbers current?
Your refractometer is calibrated and/or confirmed with another?
What salt are you using?

Another long shot, but if you have Lugol's (Iodine) you can hit the tank with a drop or two. For whatever reason -- either it is missing in my salt or something chews through it -- I have to dose Iodine. And Potassium of all things. My (infrequent) ICP tests always show low or zero. Nowadays, I've learned to read the PE on my duncan which seems to respond to Lugols well. I don't generally recommend dosing anything you don't test for, but it might be worth a drop or two.

 

[MadTownFess]

Well your stated parameters are pretty ideal and I imagine your test kits are all less than 16 mos old too.

Are your PO4 and NO3 numbers current?
Your refractometer is calibrated and/or confirmed with another?
What salt are you using?

Another long shot, but if you have Lugol's (Iodine) you can hit the tank with a drop or two. For whatever reason -- either it is missing in my salt or something chews through it -- I have to dose Iodine. And Potassium of all things. My (infrequent) ICP tests always show low or zero. Nowadays, I've learned to read the PE on my duncan which seems to respond to Lugols well. I don't generally recommend dosing anything you don't test for, but it might be worth a drop or two.

Yes I test my water at least twice weekly, I go through test kits like drugs.

All my numbers are current.

Calibrated my refractometer a month ago. I also tested water that came with new frags last week, which tested the same as my water.

Using RedSea Blue Bucket/Pro mixture (about half and hafl)

I agree my Iodine is low, the last ICP test I did a few month ago said I was only at .01. The question is, would zero Iodine cause corals to close up that much? I feel like very few people in this hobby dose it, and they dont seem to have problems.

 

[ScottB]

Yes I test my water at least twice weekly, I go through test kits like drugs.

All my numbers are current.

Calibrated my refractometer a month ago. I also tested water that came with new frags last week, which tested the same as my water.

Using RedSea Blue Bucket/Pro mixture (about half and hafl)

I agree my Iodine is low, the last ICP test I did a few month ago said I was only at .01. The question is, would zero Iodine cause corals to close up that much? I feel like very few people in this hobby dose it, and they dont seem to have problems.

For my duncan coral, it seems to retract over time when I forget to dose Iodine. I cannot prove anything in/out but there is a correlation.

I agree very few actively dose Iodine these days. They do so passively with broad-based supplements like Zeo, Red Sea, Brightwell, etc. And I will say old reefers do or used to dose Iodine, potassium and strontium. Now we assume that is in our salt mix, which may not be a sound assumption.

 

[MadTownFess]

Just to update: I did a 25% water change, and put in fresh carbon. The ACANs are all looking better today, about 85%. Hammer still looks upset, but is better than yesterday. Still no idea what happened. But happy to see things going back in the right direction.... thanks for all the insights.