What happens when I leave my tank for over a month?

[paperdesk]

I just just got back from a 4.5 week trip overseas. While gone left my tank on pretty much auto pilot. The results?

1. My two fish, RBTA (Rose Bubble Tip Anemone), shrimp and clean up crew are doing fine.
2. Most of my 20+ coral frags show clear growth, but I did lose two birdsnest corals.
3. There is was a minor increase in Bryopsis.
4. There was a "pod" explosion.
5. Most of the hydroids disappeared.

I really figured things would go much much worse, and was very glad to see the tank looking so good when I got back!

My wife fed the fish, and emptied the skimmer, but other than that I didn't ask her do anything to the tank. I have a Reef Angel controller, so lights, temperature, circulation and ato functions are automatic.

The Before specs:
Ammonia 0
Nitrate 0
Phosphate 0
Calcium 430
Alkalinity 10.2
Magnesium 1440 (trying to combat Bryopsis)
Salinity 1.023
PH 7.94
Temperature 78.4

The after specs:
Ammonia 0
Nitrate 0
Phosphate 0
Calcium 440
Alkalinity 11.8
Magnesium 1380
Salinity 1.023
PH 8.04
Temperature 78.4

I have a little kalk in my ATO supply, and it looks like I need to back that off a little.

The first surprise was that I expected the high magnesium levels to kill off or at least keep at bay the bryposis, but instead it really took off while I was gone, though only in certain areas, and mostly under the sump return line which is also the end of the tank that gets a little afternoon sunlight. No other visible algae appears in the tank, other than a slight dusting of greenish algae on the glass that gets cleaned off every few days.

Most of the SPS and LPS coral look great and show marked growth with the exception of two birds nest corals that died over the course of about one week, bleaching from the base up. I'd love some help figuring this one out, what can cause this? Could the higher than normal alk have caused it? I also wondered if the RBTA could have zapped them (he loves taking occasional walks around the tank). The only other recent change I can think of is that I replaced the filters in my RO/DI top off system a day or two before I left. The output TDS is near zero, but possibly one of the filters could be releasing something bad into the water? What is especially odd to me is that everything else in the tank seems so happy.

My wife said she saw little critters on the coral and thought they were eating it, but I think what she is looking at are harmless amphipods that had a population explosion while I was gone. I used coral rx on all my new coral before introduction to the tank, but clearly it didn't kill everything or else I wouldn't have any pods.

Another interesting thing is that I used to have a lot of small whitish hydroids in the dark areas of the tank, and while I was gone they seem to have mostly disappeared.

I'm planning to do extra water changes over the next few weeks to try and catch up but would love to know if anyone can detect a correlation between the death of the birdsnest and anything I have mentioned?

Here is a brief history of my tank:
I have a 90 gallon tank with 30 gallon sump and Reef Octopus NWB 200 skimmer. I'm using Evergrow full spectrum LED lights running at 70/40 blue/white for about 12 hours a day. My tank was started with cured dry base rock in May of 2014. I have slowly added a few fish and a number of coral frags since then. Phosphate and Nitrate have been at or near 0 using Salifert test kit since tank completed cycling. I do weekly 10% water changes and use RO/DI water.

Have you left your tank on auto pilot for a month or more? How did your tank do? I'd love to hear your experiences!

Ted

 

[kmbyrnes]

When I went out of town for 3 months last summer, I hired a 'referred' pro tank service.
Came home to algae, aiptasia, fewer fish and less corals. Just now getting back to a nice tank after 6 months.
Next time I will just hire your wife, she seems to know what she is doing and would probably cost less.

 

[paperdesk]

Lol, I'll let her know she has a new career waiting!

 

[Sk8r]

Brilliant.

I'd recommend some slow water changes. What I'm doing, to mend a period of neglect, is siphon 3 gallons a day from the bottom of the sump and replace with new salt water. Mends nutrients and picks up detritus. Continued for 10 days with a 105 gallon tank. No great disturbance of tank, but the tank reacts nicely.

 

[Clownfish Chris]

Brilliant.

I'd recommend some slow water changes. What I'm doing, to mend a period of neglect, is siphon 3 gallons a day from the bottom of the sump and replace with new salt water. Mends nutrients and picks up detritus. Continued for 10 days with a 105 gallon tank. No great disturbance of tank, but the tank reacts nicely.

I have to agree. When I red the original post at first I thought "how irresponsible" and "maybe I need to find my troll spray". Then I saw that you had everything on a controller and someone feeding the fish.

Ill be watching for responses about the bird's nest as I have no input there.

Good luck!

 

[Sk8r]

Many people find that family or business needs call them away from their tank, and sometimes the whole thing has to be left on automations on very little notice---if gran is having a medical crisis or the boss has sent you on a four week emergency assignment to Talladega, by air, this afternoon. I don't own a controller, but I do have an autofeeder, timers, and a float-driven ato, with a 32 gallon ato reservoir with kalk, and a 32 gallon backup to be switched at the two week mark. It only needs someone to push a button and fill barrel 1 from barrel 2. You don't need a big budget to have a bullet proof tank: just good planning.

 

[paperdesk]

Thanks for the input! I would have also set up an easy or auto water change system, but didn't quite get it finished.

Still wishing I could get some specific suggestions of why the birds nest died!

 

[Cymonous]

Well, I would suggest you need to raise your salinity to 1.025 or 1.026.

 

[paperdesk]

Thank you Cymonous, I forgot to mention it, but I do usually usually run it at 1.025 though it got low before I left and of course stayed that way while I was gone. I am already in the process of raising it again.

 

[BigCountry74]

good stuff man. i am impressed.

i would raise salt to 1.025-26 also. but thats just my .02

 

[paperdesk]

I just remembered one other thing. We had cabinets built in our bedroom about two weeks before corals died. Because they were built in they had to be stained and clear coated in the house. The bedroom door was kept closed and the room vented, but is it possible that the fumes could have killed off the coral? Seems unlikely, but it's just another part of the puzzle. Again, it's interesting that only the birds nest were affected so far, though some of my palys and the kenya tree have been sort of closed up for a few days. I started running carbon yesterday in case there are toxins in the water.