@esse
It's a valid question,but I am in no way an expert.
The water column on a properly cycled tank should be able to handle the bio-load with some mechanical filtration especially at the time of stress when the corals slime up. Filter sock will do, but the ones that come stick with the Fusion series block up quick so I run with the media baskets and some filter pads on the top for quick and easy swapping the day after feeding.
For starters...
1. Use RODI water, either from a LFS or if you have an RODI.
2. Be sure that the tank is properly cycled, you can jump start by using BioSpira or similar product.
3. ATO's are important on smaller tanks for salinity stability. (Am serious about the Mirco one I have, I have 2 and they both work great and only $130)
4. min 10% WC per week or 20% every other week, you may want to do the weekly change to help keep parameters in check.
5. start off slow, a couple of cheap starter corals, and read up on acclimation and dipping.
Things to note...
1. Smaller the volume, the faster things go wrong...
2. PH swings with photo periods, so far I have not been able to avoid or mitigate this in my coral QT because of not having a sump or a fuge to run opposite lighting schedule. I have gotten it balanced in my DT within .15. and it is fairly stable in my fish QT where I rarely turn the lights on. Others may have better input on this.
3. Alk will lower as minerals are consumed, water changes and dosing either 2 part or other bottled supplements/buffers is the only way to maintain (please anyone correct me here if I am wrong)
The Biological filtration seems to be no issue in the water column and once piece of LR the size of my hand that was seeded in my DT's sump. The water I used to start the tank is cycled water from my DT that was nursed back up to 8 dkh alk through several water changes before I added in my first corals.
So far it is my experience that I am only getting fluctuations in PH and dissipating Alk in the smaller tank. The ammonia, Nitrite and Nitrates seems to be fine and I recent had 14 corals, 2 feather dusters and 2 peppermint shrimp in the tank.
My fish QT is bare bottom as well but the water column doesn't see the swings with PH that is large in part to the fact I am not running the lights on the fish QT, Alk is also more stable in the bare bottom fish QT. Seems logical to me since there is not as much calc and mag demands in the fish QT. I have 4 fish currently in QT, 1 Royal Gramma, 1 Melanarurus Wrasse, 1 Yellow Watchman Goby and a Small Foxface Lo, in the 32 gallong bio cube and it's been 5 days and still no issues with bio-load even after feeding. The only thing I do is put a filter pad in before I feed then pull it out the morning after to prevent nitrite, nitrate and phosphate build up.
I believe the coral QT has PH fluctuations in step with the lighting schedule and Alk just drops from the SPS and LPS corals and that drop is what has caused me to lose some shrimp and have some color loss on the various corals...specifically Zoas and SPS. Everything still had polyp extension so at least I knew they were alive. I moved all the frags to my DT which is much more stable and everything is starting to come back.
In my DT, I would do a 20% WC every 2 weeks and I was battling low ALK and since I started a 5gpd AWC my Alk has slowly been raising and the corals look happier for it. So stable Alk is definitely key and probably more so than PH. I have bought and am probably going to start dosing the big 3 in the DT by the end of the month.
Unfortunately, short of testing daily or 2x per day for a little while it is hard to get a handle on what it is doing and corrective measures for Alk would be as note above.
One side note...I do plan to upgrade the stock return pump for the Nuvo 20 Fusion to a Cobalt MJ1200 for better flow through the tank and not depend on just the MP10 for pushing water. One of the Reps at BRS suggested it to help increase flow without having to have the power head on Max.
So I wouldn't say I am the one to talk to but I will be happy to share my successes and failures.
