[LRS078]

First let me thank Calfo and all the other very patient and passionate contributors to this thread. After 3 meals, half a dozen Advil, and a page and a half of notes I'm through all 40 pages of postings.

Thus I am going forward with RDSB's on two ~200 gallon FOWLR BB systems. No corals, few to no inverts, just fish.... In addition to skimmers, bioballs, and 100 micron socks I want to do the RDSB's but am working on the volume of sand needed.

Of course I recall Mr. Calfo's data on a 2000 gallon system doing great on a 55 gallon tank RDSB. However we don't know what kind of bioload or what other filtration was involved so there comes the dilema.

See my signature for bioload, currently I'm keeping nitrates down via water changes but its getting expensive (that or I need to buy stock in Instand Ocean). For predator/FOWLR bioloads what would be a solid/safe amount of RDSB for a 200 gallon system? I'm thinking around 30 gallons? If a 50-75 gallon system of reef/semi reef bioload does well with a 5 gallon IO bucket then we are talking 20 gallons of a 200 gallon system at the same proportional bioload. Since FOWLR bioload is considerably higher (yeah, the puffer poos ALOT) even with conservative feeding it seems 30-40 gallons of RDSB would be needed to really take out the nitrates per 200 gallon system. Thoughts?

Obviously, aragonite is preferred, if I can FIND a non LFS/aquatic source I'd be elated but locally so far its a no go at Lowe's, Home Depot, Pike's Nursery, Ace Hardware, etc. I've got silica sand coming out my eyeballs but no aragonite short of LFS channels. I've read the last 40 pages so I know its doable with silica, but I'd rather do the project to an ideal then go half buggered. LFS/internet pricing makes budget nearly impossible at $22 per 30 lbs for carib/aragamax/etc.

Filtration flow is as follows: overflows (2x) dump through two 100 micron socks (changed/washed daily) into the sump. Protein skimmer does its thing...don't want to mess up its mojo. Return pump(s) in sump at approx 18-20 hourly turnover. 1 powerhead to run a small bit of bioballs as an emergency nitrite/ammonia eliminator. Finally a powerhead that runs the RDSB which sits next to the tank. One tank is 2 years up/stable the other is new.

RDSB = Rubbermaid bin with 1/2" wide zip ties for reinforcement (just to be safe). A piece of plywood with a tablecloth to cover the thing so resident girlfriend doesn't hate it. Set fishy supplies on makeshift tablestand. Enjoy not having to change 50% water monthly....

Thoughts?