Another Setback
This tank has been a lot harder than my other two tanks. Ironically, I have been much better with water changes and maintenance, but the atypical requirements of this seahorse/soft coral/algae tank (overall lower flow but some higher flow areas plus some light) means I am in virgin territory as far as my experience goes.
I have been battling cyano -- a very bad case of cyano. Biopellets can be tough enough without the added complexities of the lower flow and the need for enough light for soft corals/macro algae. This combination has yielded a fair amount of cyano on the sand and rocks. Within a week of suctioning it out of the tank, I was seeing it cover everything again in a thick sheet.
My nitrates are 0 (API) and phosphates are 0.03 (Hanna), but clearly the cyano was consuming these nutrients, since it was growing. I focused on the typical remedies for cyano: manual removal, probiotics, flow, a good skimmer, red slim focused CUC, and CAG (/GFO):
- I found a 1/4" I.D. tubing works great as a cyano vacuum. It removes only a small amount of water but has enough suction to get the cyano whereas my gravel vacuum did not -- it removed mostly water and sand.
- I started dosing Microlift Special Blend which has certainly helped reduce the amount. I could go a couple of weeks and only about 1/2 the amount was growing.
- I upgraded my skimmer to an CPR AeroForce 2 AP (Air Pump version) and that helped even more (I love this skimmer, but not the best fit for an RSM 130D).
- I added a bunch of CUC which eat it so that has been helping: a fighting conch (great in helping the sand floor). a few banded trochus, a few ceriths, and a few Chibanarius digueti hermits.
This had really turned for the better and the cyano was getting very much under control. I decided to try CAG as well. I had been putting ChemiPure Elite in my media basket, but I decided this weekend to add a TLF 150 with CAG. I had some Kent Marine Reef Carbon (not a recalled batch, I checked) so I used about 1/3 cup. I also used some ocean water from my LFS. It is at nearly the same salinity as my tank water (1.025 versus 1.026), so I figured a 5 gallon water change would be OK. I had done this before without any issues.
Well, something did not work out as I woke up this morning and my tank was partialy crashed. The Xenia was withered, the Toadstool was gray, but the worst part, was that my awesome 5 months of growth of my Red Grape Algae (Botryocledia spp.) was all coming apart: the little grapes all floating loose in the tank. The seahorse and snails seemed fine and were eating and showed no signs of stress. The only good thing is there was no sign of any cyano anywhere. Maybe I did not rinse the GAC well enough or there was some contaminant somewhere. I don't think it was an issue with the salinity since the snails were fine or it was an issue with copper since the shrimp and pods seem OK. The Red Gracilaria and my sea fern also seem fine.
The Xenia was toast, but I moved the toadstool and the Red Grape to my 120G. Time will tell. I also removed the GAC for now. I wish I know what the cause was, but I made two changes at once: water change with water from a new source and added GAC. There were also a few different containers involved since I added the TLF reactor and rinsed the GAC (in tap water, not RO). One idea is that is was too much GAC too soon and it stripped the water?