Ichthys, if you are back to square one using a 40g as sump/fuge IMO save your money and skip the traditional CL and utilize your return pump for needed flow. I have a 40R acrylic that is approx 4/5 lighted fuge (24/7) and 1/5 cryptic fuge separated with a black acrylic baffle. My system pump is an Iwaki WMD30RLXT producing about 950gph, 27x + per hour through fuge stuffed with Caulerpa species & Chaeto over a mud/sand bed. I made a spraybar out of 1-1/4" PVC at end of drain into sump to evenly disperse accross fuge. The macros act as a bubble trap and have done extremely well in high-flow as have the abundant pod population. I have a heavily stocked mixed reef in which I feed the fish generously and have no Nitrates or Phosphates to speak of but because of all the macro do need to dose Iodine (Lugol's Sollution)
Anthony Calfo and others have discussed the benefits of having higher flow rates through fuges and have dismissed the 2-5x myth (on the natural reef macro algaes thrive in heavy flow areas) here is an insert from one of Anthony's earlier posts on RF on a piece about SPS coral Stylophora.
For me... I dont keep as heavy of a fish load in my tanks as I recommend. Subsequently, I depend heavier on my DSB, refugium and the (heavy) feedings of my invertebrates collectively with hope (I have not measured this, of course... its beyond my skills/equipment) that I am supplying enough feeding opportunities incidentally in the process. More bacteria, more larvae from infauna (in my sand/rocks, etc), more mucus/"floc", etc.
In plain language - a regugium and/or deep sand bed is a small but useful and important support, but not the principal means of feeding Stylophora here.
I have seen and can imagine a number of different ways in which aquarists succeed with the keeping and growing of this beautiful coral:
- bare-bottomed tanks with lots of rock and a heavy fish and/or invert load (feeding them)
- DSB with light fish load but heavy water flow and (likely) strong feeding of other inverts (LPS, seastars, shrimp, etc)
- either or neither of the above scenarios, but with a large refugium that has good (over)flow... none of this piddly 10X per hour turnover or less Real water flow... 20X+
There are many successfull ways of reefkeeping and to me the ideal system would be to have a high-flow fuge seperate from an equipment sump as well as a high flow frag/growout tank all plumbed into DT as you would a multiple closed loop system. This also happens to be my actual plans for a larger system of 500-700+ gallons overall which I hope to start as early as next spring. Here are a few older pics of my existing fuge set-up.
Todd