I would not use the upright tubes as ken said they will speed up the process but eventually they get removed. Also it is hard to stand the tubes up unless you have an under gravel filter to hold the tubes. I would get some sand from an established tank to seed the sand and forget the tubes all together
im nowhere as experienced as most of these guys with the plenum, but it seems to me its not that complicated to build really. u just need a dead space under the sand… build a sort of frag rack. 1" or so tall, covering the entire area of the tank floor. cover the egg crate with something fine enough to keep the sand on top. cover it and forget about it. keep as much of the surface clear as possible (for h2o exchange). and keep ditrius and junk off the sand to prevent clogging. and then wait. might take a little bit to seed, but i wouldnt figure it would be much longer than the cycle of the tank itself. “nothing good ever happens fast in a reef tank”
Its nothing complicated. i go whole hog and cut 8-12 inch sections of 3/4 ID pvc, drill some 1/4 inch holes through them every 3 or 4 inches, for water difusion, and leave the ends open, no caps. cut the egg crate so that it has about an inch free space to all the tank walls, it wont show then. then i tie the pvc to the egg crate with some 80 pound test nylon braid fishing line around the parimeter and some down the middle for support. leaving a gap between the pipe ends. they are just support for the egg crate, screen and sand. you can then lay this in the tank, and cover with plastic window screen so that it lays over the edge of the crate, adn on the bottom. then cover with sand. or whole hog, i gift wrap the whole eggcrate/pvc assembly in screen, folding it under and tying in place with more fish line. just being neat. and insuring no sand fills in under the screen and crate. it has to be a dead water space on the bottom of the tank, under the sand.
http://www.garf.org/bulletproofreef/plenum.html
something like that, to allow even difusion under the crate. I like to leave gaps and drill holes in the pipe to all that and prevent a super anerobic area building up in the pipes.
ever looked into a diy denitrator?? just check one out on “about.com”. seemed pretty simple, and takes the same amount of time to seed as a plenum. less hassle, and easier to remove IF there ever is a problem. (not saying there will be) as long as u get the flow set right, seems plug and play.
side note on the plenum:
make absolutely sure that in no way does any light reach the underside of your tank. this is the reason y most people shunned the plenums right around the time refugiums became popular. light plus nutrients grows algae, which produces o2 and even the slightest amount of o2 will completely destroy any anaerobic zones u may have. not sure how u r set up right now, or plan on setting up in the future… but definately something that needs to be addressed. (pretty sure kaptken covered the bottom of his for the same reason)
Although i already brought up the denitrator i would like to emphasize a point fishguy made.
The reason your started this thread is because you have an NO3 problem and your not sure of the cause so your beginning to suspect different things(i.e, sandbed). What if you install this plenum and you still have a nitrate problem? IMO its will be difficult to troubleshoot and “fixing” a plenum is pretty much impossible without tearing your tank down.
If you have a denitrator you can test your nitrates right at the effluent. You will ALWAYS know its working. Also, you can adjust the denitrator very easily to accomodate a changing bioload. If your nitrates are going up, ramp up the effluent. If your starving your system, dial it back. If your denitrator crashes, take it in the kitchen, rinse the media, put it back together and in 6 weeks voila! Working again!! Easy as pie. I cant imagine going with a plenum over a denitrator.
[quote=“logans_daddy, post:45, topic:1663”]
The reason your started this thread is because you have an NO3 problem and your not sure of the cause so your beginning to suspect different things(i.e, sandbed). What if you install this plenum and you still have a nitrate problem?[/quote]
I thought he was looking for ideas for a solution not necessarily a cause.
Just want to add if you do the plenum and plan on testing the results don’t expect a miracle the next day. In fact disturbing what you have will spike nitrates for a while. The plenum will take time to get established.
eh, maybe ;D
don't expect a miracle the next day.
+1
that is correct. a plenum will take 2 or 3 months to fully cycle up, although i noticed the nitrates start to drop about the secornd or third week when i first set up my 75 ten years ago. a denitrator will take a few weeks to a month to get going too.
A RRDSB will take the setup time as well. It is also external (remote) from the tank so if it turns into an issue it is easy to pop out of the system.
So many options! As always many ways to skin the cat.
i have 0 nitrates in my 180 now. but i think i am gonna build me a denitrator. after checking into it, looks pretty simple, cheap, and worthwhile. an insurance policy if u will.
insurance policy if u will
bingo!
thanks for all the help guys! tru i could still have nitrates after the plenum build, but im also upgrading my skimmer to an octopuss, and im gonna turn my aquaclear box filter into a mini refugium. i think that your right about the initial spike after i stir everything up, but the fact is, i rushed into the reef thing too quickly, and i just wanna start from scratch (although im hoping that all my fish and corals will survive). im gonna start a new post on the “rebuild” on the weekend of the 4th, so you guys can witness the transformation.
thanks again for all the help guys!
good luck!
looking forward to the build thread.