Hi guys, I have finally found some time for writing up an update!
Quite a few things have been going on over the last 3 months (let us say, 18th April 2022 - today) in the 3-tank system.
First anecdotal issue I had early that period was that I ran out of salt and I went into a 2.5 weeks period where I did not perform any WC. The system and all corals were very good so far, so I did not think anything was gonna happen. Wrong! First warning signals: some of my montis and my master lobo started to fade out, loosing its coloration.
Looking for culprits I realized that my (3 months old) tunze care magnet had rust on the wet side.
I never left the magnet inside the tank, but I thought that it may have leaked some metals when I used it to clean the glass. I immediately sent an ICP and it came clean regarding metals. Only thing out of place was iodine, which hit 0 ppb. Waving through r2r, I found other posts where people was talking about issues with montis (and other corals) and zero iodine. Maybe this is another instance where this has been observed, or perhaps the issue was a completely different thing. Or maybe it was a combination of two or more issues: during 2.5 months I have been dealing with green cyano, which I will turn on to discuss later.
Anyway, at that point I was leaving WC as the responsible of replenishing the trace elements, and in this 2.5 week period of no WC I just saw how fast some elements are depleted in the system. To revert the situation, I got some salt, I made a 400L WC (25% of the net volume) and I started to dose Red Sea trace colors ABCD. Things improved substantially. In just ~2 weeks the montis recovered (partially) their coloration; lobos instead are slower and it took a couple of months to see some progress. 1 month after the 1st ICP, I sent another one just to check whether my iodine dosing schedule was right, and this time it came 44 ppb. Lesson to learn here: never, ever, skip your WC!
Excluding this time, I never skipped a WC, and I was doing 220L (~12%) WC on a weekly basis. The nutrients were, according to testing, under control, however, green cyano showed up by the end of April. People say that cyano is harmless, but according to the experience I will describe next, it is harmful, or it may fuel/be related to harmful pathogens. This is the only explanation I can find to what it came next. I am describing the appearance of cyano after talking about the montis issue, because I realized about its possible connection once I had the perspective. Summarizing:
- 22th April - Green cyano appears.
- 22th April - 8th May 2022 - I skip WC. Some corals (montis and lobo) started to fade out 1st May 2022.
- 9th May 2022 - I perform 400L WC and started dosing trace elements. Montis recover quite fast after that.
So, my guess is that green cyano combined with no WC and iodine hitting 0 was the cause of the issues reported so far. At least, there is nothing else I could see/measure that is known to have negative effects. However, the cyano appearance certainly suggests that something in the biological cycle was off. As I said, after the 400L WC corals started to come back, and I haven't skipped any WC since then. Still, I could not get rid of the cyano until I eventually used Chemiclean the 8th July.
So let us turn on now to the cyano issue. I have been dealing with green cyano during 2.5 months. It covered some big portions of the sand bed and large regions of the rock aquascape. During that time I have always performed WCs (excluding the 2.5 week period mentioned before), the flow was really good and nutrients were not specially high (3-10 ppm of NO3 and 0.03-0.08 ppm of PO4). At the ~1.5 month (around 10th June) mark after appearing cyano, a considerable amount of LPS started to STN (very slowely) or stopped to grow. However, this time the montis were unaffected. The pic below was taken the 20th June.
I was suspicious of the cyano, so I went a bit heavier on removing it during the WCs and I also started to remove the sand bed. At this point I started to think about bacterial issues and then is when I really considered using chemiclean. I did never use any chemical quick-fix product before, but after reading all the posts out there and talking to some US hobbyists, I eventually decided to use it. I strictly followed the manufacturer guidelines. The timeline in this case was:
- 22th April - Green cyano appears.
- 10th June - Start to notice STN and very low growth on a considerable amount of LPS corals.
- 15th June - 7th July - I progressively remove the sand bed during the 12% weekly WCs.
- 8th - 10th July - 50h chemiclean treatment.
- 11th July - I perform a 450L WC. Cyano is gone, no casualties so far.
- Today 17th July - It is still early, but so far, the rock is clean and looks super healthy cured live rock. Water is crystal clear, and my goni (which is a very good warning/probe coral) looks more happy than ever.
We will see what comes next.
Btw, I set up again the tank I used as a quarantine/holding collection system using some spare equipment I had. I used the 2/3 of the rock aquascape I did for the 100g. The 100g was never maintained (in a year, the system did not even produce coraline algae and nutrients were out of charts) and I recently decided to took it down. Since I love the aquascape I built, I decided to use it on the smaller tank (net vol. 150L) I had stored. My plan is to run it very simple: bare bottom, no sump, just an ATO system, tunze skimmer 9004, heater, flow and light. The aquascape (marco rocks) is 1 year old, so in terms of managing ammonia it was like an insta-cycle. I have added a small indo rock from the 3-tank system to help the maturing process. The idea is to run the nutrients high and collect some zoas and mushrooms in there. Here a today's pic:
The 100g tank will be linked to the 500g system when I set it up in the (far?) future.
We are just awaiting for the glass and we will proceed to assemble it. It is gonna be fun to build the sump directly into its place. There is no physical way to building it outside and then fit it in in 1 piece. We will take our time for building up a nice dry rock aquascape and we will cycle/mature it with some of our indo live rock in the sump. And given that we have no rush, this time we will fully quarantine the live rock and corals before putting them into the new system.
