Most PnP's have some intrinsic problems when used as SH setups. Here is an older post of mine that is "stickied" over on the org:
Ever since their inception, it seems as if this question has been asked with an increasing frequency. As the owner of four such systems, three JBJ Nanocubes and an Aquapod, i feel i can speak first-hand/real life on the issue.
1. 8's, 12's, 14's are all too small for SH, unless you plan to keep dwarf SH. you need at LEAST a 24, 28, or 34 gal.
THE FIX:
there's no getting around the size issue...you need a large enuff tank, whether it's a plug 'n' play (hereafter, PNP) or a regular system.
2. ALL of these systems typically run at 80*F, which is at least 6*F too warm even for tropical SH. this is a very important factor, as SH tend to be prone to bacterial infections, especially at warmer temps due to an increase in bacterial count. you may hear "SH are found in 80*F water in the wild", but you must remember that the bacterial concentration in a closed system is infinitely greater than that of the ocean.
THE FIX:
get a chiller. this is the best and most reliable way to go.
there is an Integrated Chill Assist (ICA) offered by NANOTUNERS, however, this is a tuff mod to acomplish, and it's not really a true chiller in the sense it runs 24/7 and there's no temp set. what it does is cool the tank down at night to give you a lower "baseline" temp in the AM.
however, you can get a temp reduction of about 2*F-3*F by swapping out the stock pump for a cooler-running model (e.g. get a pump that consumes fewer Watts). this will also help with the flow problem (see #3). i've found that Maxi-Jets are a good bet here. it only takes about 10 mins to swap out the pump. depending on your flow scheme, a MJ 400 or MJ 600 are good choices.
also, if you have one of the "open sump" designs where the top of the filtration area is open, run a fan over it. leave the "feeding lid" open. if you have a glass covered HQI model, remove the cover and run a fan over the water surface to increase evaporative cooling.
3. the flow in these systems is too high.
THE FIX:
you can replace the stock pump with a lower flow model (if you choose a lower "wattage" pump, this will also help with the temp, see #2). you can also split the reutrn by removing the stock nozzle (it just pulls off) and adding a locline Y connector and the fittings of your choice to split the flow up. this also helps with being able to direct the flow to remove dead spots.
PROS
the PNP tanx go up quickly and easily, and they make VERY pretty tanx. they're also compact and fit nicely where space is an issue.
hopefully, this will answer the most FAQ regarding these tanx.
