sandbed question

[glassman]

this weekend i will be going through the process of emptying my tank, getting rid of the undergravel and canister filters and replacing with a sandbed, overflow box, sump and protein skimmer (oi). it's a 55 gallon tank and will eventually have about 100 lbs LR (currently 67). i have 40 lbs LS, 20 lbs aragonite, and 40 lbs crushed coral left over from my original setup. i was wondering if it might be a good idea to use all three, and if so in what manner. i was planning on using the simplified LS approach outlined in tullock's natural reef aquariums book (no plenum), before i considered the possibility of also using that leftover crushed coral. would layering it be a good idea, or mixing it all up?
i would also like to hear your opinions on the pros and cons of this setup, as well as suggestions for optimizing its use. the sump is a sealife systems model 100 (i will be using LR in it in place of the bio balls). the venturi protein skimmer is an amiracle vps 1500. the pump is a mag-drive 9.5 and there are two aquaclear 402 powerheads in the tank.
thanks for any input.

[Doug1]

How big are the crushed coral pieces? If they are large(>3mm) they will eventually wind up on top as the finer stuff settles. You can toss it and use oolitic aragonite as the snd base and put the LS on top, other wise it will surface and create a trap for detritous

[reefguy]

you know, doug, i TOTALLY respect your responses, BUT, i must graciously disagree on this one. i have had my reef up and running for over a year. the substrate consists of 60 lbs of live sand OVER 20 lbs of crushed coral. i have NOT seen ANY ill effects of having the crushed coral in my tank. actually, the contrary has happened...not ONLY has the CC stayed on the bottom, but it seems to provide some stagnant, open areas for denitrifying bacteria to flourish. to my surprise, the crushed coral has stayed on the bottom for over a year and continues to do so. the trick may be to add some really fine sand to the crushed coral before topping off with live sand. the fine sand settles and "locks" the crushed coral in place so that it can't move. this is only from my experience...hope this helps

[glassman]

thanks for the responses. i finished the change and decided to just leave the crushed coral out of the tank. i will probably get another 20 lbs of live sand when i put in the last of the live rock, which will occur as quickly as my budget will permit. i didn't plan on spending quite so much on the sump/skimmer/sand this weekend. darned credit cards are so tempting. my dilemma now is that i can't seem to find anyone who carries the suction cup attachments for the back of my powerheads. it makes hanging them in the tank a little tough.

[Doug1]

Reefguy I think you may have hit upon the key there, using oolitic sand to lock it into place. Originaly I was going to suggest fiberglass screen over the CC , like the sepration layer often used in plenums but decided that was making things to complicated. The large chunks surfacing is a common occurence after adding CC, oolitic and 1-2 mm substrate particles and mixing them up as mentioned in the original question.
Glassman, finding decent suction cups is a real challenge If you can get some acrylic strips, you can heat and bend to make the hook part then secure the power head with a zip tie. Another trick is to shove a length of coat hanger wire into airline tubing then heat the ends and press together to seal it. This stuff is really handy as it easily bends to shape as needed