Nano Crash?

[NaCl_H2O]

Ok all you Nano pros out there! The other Nano post reminded me to post this question.

Three months or so ago we bought a 12g "Nano Cube" that the wife setup with one nice (large) piece of LR, and mostly a few gobies, etc. Then we added a Zoo or two and other small stuff. It was doing fine up until about a week ago.

Woke up one morning and all the fish were "panting" and zoos, etc. were closed up tight. The PH had sunk to < 7.6, Alk was 6'ish. We had been topping off Kalk water, but switched to plain RO/DI about 2 weeks prior.

We did a big water change (50%) and added an airstone in the filter compartment, and some buffer.

It is stable again, and only lost a cleaner shrimp. I have left in the airstone, and have resumed topping off with Kalk water.

Any thoughts as to what happened? An Alk/PH crash after the new substrate settled down and then I stopped the Kalk, or just low Gas exchange?

This Nano stuff is new to me ... they sure can change overnight, literally!

[Instar]

I would not kalk live rock, gobies and zoos. I never do that in my nanos anyway. Just change some water every week or so. No additives at all except maybe a drop of vitamins or something, so long as you use an established salt mix like IO as opposed to one of the new fad craze salts. Kalk topping in a nano is going to get the buffer system way off. Its too easy just to change some water. And a large piece of LR in a nano? Lots of room for decay inside that thing and that can change things for worse over night. It will be alright after it gets all the junk purged from inside it, but, any odd thing could die in a large rock and totally mess with a nano sized tank. That would cause low O2 retention for sure.

[dan]

i'v never had a problem in my 250 nano. LMAO :P :P :P

[NaCl_H2O]

i'v never had a problem in my 250 nano. LMAO :P :P :P

Dan, when ar you going to get a respectible tank!

Larry - The LR was in my other tank for over a year, it was VERY well cured. Forgot to mention my Amonia & Nitrite were 0, Nitrate was maybe 5-10.

[GaryP]

I agree with Larry. Just being off by a very small amount can cause a huge swing in chemistry when you are adding additives, especially something as "aggresive" as Kalk. The way I recommend water chemistry management in a Nano is through frequent water changes, not additives. I do weekly 10% water changes. As for oxygen depletion, that shouldn't be a problem UNLESS you had something die or detritus buildup that increased decay and the biological oxygen demand (BOD) of the system. A hair algae outbreak could also cause problems at night when the alga aren't photosynthesizing and are using O2 and creating CO2. The low pH you mentioned makes me thing there may be a gas exchange problem somewhere especially if you are adding Kalk. Again, the small size of the system hurts you there. Of course, a lot of decay going on could drive down your pH as well. The bugs are producing CO2 as well as organic acids as they eat waste. Increasing circulation with a micro powerhead could also help with all these problems I mentioned. I think most off the shelf Nano systems are a bit low on circulation. That's the whole problem with a Nano, there is no such thing as a small upset, because of the small volume of the system, everything is major. Everything is amplied by the size of the tank.

What you may want to consider doing is installing a small air driven skimmer like those that Felipe puts in his eclipse retro systems. That serves double duty for both oxygen saturation and waste removal.

[NaCl_H2O]

What you may want to consider doing is installing a small air driven skimmer like those that Felipe puts in his eclipse retro systems. That serves double duty for both oxygen saturation and waste removal.

That's an interesting thought, I haven't seen one of these mini-skimmers, anybody have pictures?

BTW - Water changes were very frequent (daily) but small (0.5g), have changed to twice/week 3g water changes too. And I use "fresh" water from my big system.

The algae could also be contributing, there is a fair amount of hair algae right now.

[GaryP]

Put some micro blue legs in there and that should help a lot. You may want to also consider switching to some Tonga branch. IMO that helps circulation by allowing for an open LR architecture. The micro blue legs will also help minimize detritus buildup and will scavenge any fatalities you have. That's a pretty aggresive water change schedule. Try checking the alkalinity of your water change water to see if its low. If you are using Oceanic that may be the case.