1st large terrarium (4'x2'x2') set up

[beckdg]

i'd say 2-6 fans depending on placement and tubing. i'm thinking 4 is a well rounded number that'll do you pretty good even if they're not rated well in the cfm category and your placement doesn't wind up perfect. if you can make a vent tube for them with both sides plumbed to and from the tank that'll help keep things more stable.

[spiders_r_us]

I've got two Yabbies in the pond! Not really big enough for two of them but they are eating my brothers plants and fish so they have to be nice to each other for a little while.

Originally Posted by beckdg

i'd say 2-6 fans depending on placement and tubing. i'm thinking 4 is a well rounded number that'll do you pretty good even if they're not rated well in the cfm category and your placement doesn't wind up perfect. if you can make a vent tube for them with both sides plumbed to and from the tank that'll help keep things more stable.

Thank you! Except I don't understand what you mean by tubing. The 12cm fans with >100cfm I would get depending on how noisy they are (40+ dBA). Otherwise the next one down is the 8cm with only ~30cfm.

What determines a 'perfect' placement of fans?

My plan is to have one 8cm fan getting fresh air 'IN' above the rock pile where the orchids are. Then with the 'OUT' in the opposite side of the tank. With one or two fans (8 or 12cm) circulating air within the tank (if required). My plants (current + future additions) need moist or moist-ish soil but they do not require high humidity.

[Epiphile]

I believe that the tubing Beck was referring to is in connection with this style of circulation: Fan Placement on 55gal

It's useful in keeping the fans out of the way, and recirculating the humid air already in the viv as opposed to drawing dryer air in from outside. If humidity's not too big of an issue (I don't know how humid your area is throughout the year), you may be fine with bringing fresh air through the tank. Just keep in mind that the area below the intake will become dry faster than everything else.

To me, perfect fan placement is such that it creates movement in all areas of the tank, as well as keeping the glass clear.

[beckdg]

correct epiphile... i would like to point out that we have yet to see a perfect recirculation system... but that is an excellent example.

perfect fan placement... circulation throughout the enclosure, clear front glass for viewing as well as the ability to maintain a stable environment. for the last requirement i'd suggest no fans particularly blowing in or out. a screen or vent should provide more than enough fresh air and with the air moving things should move to equilibrium with the outside environment fairly quickly. blowing air in or out will constantly dry your enclosure.

i like to use the word vortex. for a large enclosure like that it would be highly beneficial. think about it as a kid in a pool walking around in circles trying to create a whirlpool. if your fans are placed in such a way that they work together they'll be much more beneficial to you. sooooo.... aiming them to the right along the back and to the left across the front will help you accomplish this... or something similar.

[pgaks2]

Originally Posted by Epiphile

If you can find a couple old computers lying around, just rip out the case fans- I think they're three or four inches across. They're free, and they'll do the trick. Mind you, they're pretty cheap in the stores, too, but still- free.

if you using this method grab the bower supply, its already got the connectors for the fans, it has the power to run alot of fan since your not running a MB,, you will have to create a jumper wire between the MB + and - connection though so it will put power to the other rails. ive used this trick a few times to run lots of extra fans in a pc for better cooling. plus it saves the cost of a good 12V converter.

sheb

[beckdg]

over the longrun that's more expensive though. the smallest power supply i've seen is 250 watts. the fans themselves run on milliamps... usually less than a watt. you'll pay more than the dc converter costs in your electric bill. either way does work fine.

[spiders_r_us]

Cool, cheers everyone.
The air circulating fan hidden behind the tank is a cool idea! but I sadly don't have enough space... or do I... I suppose I could remodel the hood for that purpose.

Just an update.

I've had one fan running in the tank for two weeks now and the leaves+fronds are swaying but I will try 2 fans later in the week for more complete circulation.

The reservoir isn't working again. I think either water is seeping up the reservoir wall through capillary action or water is seeping through the reservoir wall. Anyways the palu? will now be a terra till I get back from overseas in March.

I have fungus gnats! damn bloody dipterans. I am introducing "insect control devices" (I like the term beck). Too bad the Sac spider slings have all dispersed and the huntsman slings (2 broods just hatched) are too big to eat the gnats. I would just love to see orb-webs in between the fern fronds beats having yellow flies traps in there any time.

Anyone had problems with gnats or have solutions that work? I'm gonna try the dry ice method when I can get some from the lab, but then the spiders/slaters/centipedes... anyone tried the potato trick?

[Epiphile]

Searching fungus gnats here will get you a variety of ideas on how to combat them- they're common (and apparently don't even respect continental borders) in this warm, wet hobby of ours.

I'll put my vote in for carnivourous plants, just because they're neat.

Shame about your reservoir- hopefully you can get it sorted out when you get back.