Twin 12G Long Refugium Setup
A little background:
I want to ask about an experiment I'm putting together before I get too deep in to it. I'm interested in utilizing two 12G long (35.5" X 8.5 X 9.5) tanks with one being a planted display and the other being a refugium containing moss and RCS.
I come from more of a reef keeping background, but I have a low tech planted tank that I've kept for 6 or 7 years. It's an oddball 16G cube (15.5"^3) that I plan to convert to a watchman goby/pistol shrimp habitat.
Proposed set-up: The basic idea is to have the front display tank (12G long) raised on a ~36 X 9 X 6 wood platform on the desk I'll be using for the stand. I wanted to place the second tank, the "refugium" (also 12G long) directly behind it, flat on the desk top, so approximately 6" lower, but otherwise completely parallel to the display tank.
Refugium components: To accomplish the circulation I will use a CPR overflow box with aqua-lifter (300GPH max rated spill, but I plan to circulate about 120GPH if it all works out) and an appropriate sized return pump forcing the return water through a media reactor chamber (Aquamaxx brand) filled with Seachem Matrix for biological filtration. I know, this is where it starts getting even weirder. The refugium will also house a HOB filter with Boyd's Chemipure (which I have been using with good success on my other low tech cube). The overflow box will have tubing running into the refugium with a simple media sock at the end to act as mechanical filtration so I can rinse as required. In-between the inlet and return pump I want to start off with a couple handfuls of java moss (or other, similar moss) and a mineral stone and some almond leaves for a group of RCS (how many to start?). I also have an appropriate wattage heater that will go somewhere in the refugium.
Display tank lighting: I am thinking a Current Satellite Plus 36"-48 with the additional 15min ramp timer. Actually already ordered it after receiving a Finnex 24/7 that I returned because it was broken on receipt and that I could not use with a ramp timer the way I wanted to.
Display tank hardscape: Bogwood from my current low-tech and lava rock in the corners to plant on in an effort to conceal the return hose and overflow box. A few almond leaves strewn across the middle, which I will presoak if necessary and replace periodically (I have a ton of these already).
Substrate: 7lbs. Flourite black sand, in a thin (1/2") layer across the middle portion of the tank. 4lbs. UP shrimp soil at the base of the lava rock, at each end. I may not need to use all of either bag, leaving me some for gradual replacement down the road (but I don't know).
Planting: I want to keep it simple and I have these same plants in my cube, so I would like to keep using them, but just more of them: several java fern tied to the lava rock as midground/background, and red lily bulbs at the base of the lava rock (in the UP shrimp sand). I might start with a little osmecote under the UP sand. Yep, that's all the plants I'm planning on. And maybe some frogbit depending on how it goes with keeping the red lilies in check. And of course the java moss in the refugium.
Fauna: I have a few ideas here and this may be controversial, but this is where the RCS in the refugium might make a little more sense. So I would like the RCS to breed and provide nutrition for the fish, while also maintaining a colony of RCS in the refugium. I will also feed both the fish and the shrimp / snails, I do not intend any kind of total closed system. I'm basically going to use the RCS kinda like copepods in a reef refugium. I Would either like to keep a small number of peacock gudgeons (a male and a couple females? 2 males and 3 females?), or a group of maybe 6-10 sparkling gouramis. Last option: a super spiffy red dragon betta. The sparkling gouramis would be my first choice. This is going to be a species tank, not really a biotope (as you can see). I will also have RCS in the display tank and I am going to get the plants going, then get the RCS established and breeding, then the fish. If the fish don't eat the RCS, that's fine with me too - I just won't keep the extra colony in the refugium.
Additional fauna I plan are ~10 horned nerites, ~3 olive nerites (both of which I already have). 2 Amano shrimp, which are large and that I already have. Chopstick snails (how many?) to keep the thin layer of substrate under the almond leaves stirred (these are something I have never used, but I am thinking of them like nassarius snails in my reef tanks).
Frequent water changes (weekly or biweekly, 10% or so once everything is cycled and well established) and the addition of liquid ferts.
This is where I know I need the most advice. Somehow, I have had my current planted tank thrive with very small additions of iron as the only added fert. I have been adding 0.5mL with every 2 gallon water change, weekly - but skipping the 4th week. Its a 16G with java moss / java fern / anubias / and lily bulbs. The lillies and anubias have both responded like crazy since I started using the iron about 9 months ago. It has a HO flourescent at 10,000K that I only run 6 hours per day. I have zero algae and consistent plant growth that I rarely need to trim, but that has been looking healthy for many years. Is there something wrong with continuing to fertilize like this? I have Amanos, nerites, 2 corys, 6 neon tetras, and 3 lantern eye tetras in this tank and the sub is flourite black (not sand, the bigger stuff).
Excuse my rambling, and any feedback is much appreciated. The components I have selected reflect things I already have in my possession and my budget for a few new items. If you hate the whole idea, I can take it. If you see any tweak, just let me know. If you did read all this you're a trooper - thanks in advance.