Robert Smith

This'll never be economical, but it will be sexy. Sell it on the high tech sexy factor. It's cool. You can even sell it as "natural" (normal sun cycles, dawn-dusk, movement across the sky, cloudy days, the moon, yadda yadda yadda) I don't know much about LEDs, but I know that the ultra-bright white LEDs cost about US$1.00 to OEMs. That's the cheapest they get to anyone anywhere. These are designed for pulse applications (up to 1.5A for a few 10's of milliseconds) so they may be over-engineered for low current constant-on applications like this. The packaging and heat management is where most of the technical value lies in LEDs. Get that wrong and your LED is cactus quickly. I use 12V tungsten halide because I have no headspace (50mm clearance) and I built it all myself for about $20. I recommend against 12V CCFL, the bulbs I've managed to find are unreliable (and expensive, they're about $20 vs $2 for tungsten halide)

I made a trap using a small glass bottle (with a neck smaller than the fish, they like the bait too!) with nylon fishing line tied around the neck. I put a bit of cucumber in the bottom of the bottle and drop pedt into the tank each evening and the next morning pulled it out with a few snails, repeat until you've got them all. This did work, but was not 100% effective. I usually digitally grabbed as many as I could (and those I could quite grab I just squashed).

OT(ish): We have a baby and she went to baby swimming classes in an indoor heated chlorinated pool for a while. Some of our friends in Europe were horrified and said that's a big non non. I did some research and it seems that it can be a problem. Apparently the chlorine used to disinfect the water reacts with the biological bits (you really don't want to know) and gets converted to nitrogen trichloride (NCl3), a gas that is slow to disperse. It's this NCl3 that causes the smell of "chlorine" and the irritation of eyes etc that you can get, not the chlorine itself. Well, to cut a long story shorter... this causes significantly increased risk of asthma & bronchial problems in children (plus various measurable effects in adults). Thus, no baby swimming classes in chlorinated pools and we have no non-chlorinated pools (apart from the fish tank and the sea!)

Most plastics pumps etc are made from PVC. Clean the broken bits well with soap & water and maybe a toothbrush. Dry it thoroughly and then use Araldite epoxy or similar. The problem with small parts like this that are under stress is that they can break again very easily. Another possible downside is that the imperfect part can contribute to pump noise.

I was wondering what the big deal was, the temperature wouldn't drop that much. then the comment about it being nearly winter made me do a double take. Caper's in Nova Scotia! Boy it gets cold there.

He's pumping air out of the top of the tank. If you don't do this it will eventually empty out (drop out the hole in the bottom!) because of the air bubbler and evaporation. You need a powerful air pump to do this. You are effectively lifting the weight of all that water. The higher the tank the more powerful the pump required. This is very cool, but has some downsides: - If any seal fails to any degree or your pump fails and you don't notice (like you're on holiday) then you get one hellova mess. - The oxygen content of the water is likely to be lower than normal. This is because the air in the top of the tank is at lower pressure than atmospheric (the weight of the water reduces the pressure in the air space, or creates a partial vacuum). I think that for every 1m of water height (before any air gets in), you get about a 10% drop in atmospheric pressure, which means a 10% drop in O2 content in the water. This is compounded by the high humidity of the air in this space. High humidity also reduces dissolved oxygen (as does temperature).

Thanks Ira, Yes, water pumps. I'm loathe to pay out so much for a small Eheim pump. And my previous experience with cheap pumps was bad, so I was looking for something in the middle. Thanks for the tip on Laguna.

Hi all, I'm about to replace an older external cannister with a home-made system and was looking for feedback on pumps (submersible, for a 100L tank) that are quiet. The old Pegasso is just making too much noise. 1) Is it quieter to use a high volume rated pump at only a fraction of the rated capacity or is it better to run a smaller pump flat out? - My existing filter just runs at constant speed and the outflow is controlled by gradually closing a valve. I could see that this half-open valve could generate noise. Is this the case? - Can you buy pumps with variable speed or do they all just have on/off? 2) Does immersing the pump in an external 'sump' make them quieter? I assume yes. 3) Any recommendations on cheap(er) pumps, say: - Eheim (which I assume is the gold standard) vs - Hailea - Hydor - AquaBee - Others?

The danger of pumices, scoria and the like is that the nasties leach out slowly over time. Pumice that has been floating around for hundreds or thousands of years may be well leached, but how do you know? Even acid washing will have little effect. The nasties are in the sealed gas pockets. The fact that they are sealed makes them unwashable. They slowly permeate through the rock over time. The upside is that fish don't usually live long enough for this to be a concern. But to be safe I'd leave the pumice/scoria under water for a month before using. I think the acid wash is overkill.

For a tank that small you could use 12V tungsten. See this link. http://www.fnzas.org.nz/fishroom/2-vt15 ... l?start=15 I use these and despite the low colour temperature (3500 to 5000K) my fish and plants thrive.

To clarify, the pump won't be submersed, it'll be a sealed inline pump feeding the cannisters.

Birdy, I was intending to build a sealed system, similar to an external cannister filter. I was intending to use flow-through filters made from cyclinders (large diameter pipe) with inlet at one end and outlet at the other. Pack the cylinder with media and perhaps some baffles to ensure the media doesn't settle and create a direct path through the pipe. The fatter the pipe, the lower the pressure, but the more space it takes up. External cannisters are just really fat pipes. Bob

I have a small tank (100L) in the lounge of an apartment, so garden hoses and 600L tanks are out of the question. I vac out into a 20L bucket and use the vac to siphon back in treated fresh. What I've been trying to get for a long time is a discreet plastic 3-way T ball valve (that doesn't cost $200!). With this on the input line to my external filter I figured I can stop the pump, switch the valve from 'through-flow' to begin a siphon into the bucket, let the tank empty out 20L (intake is low in the tank), close the valve then dump the old and bring the new water. I then switch the 3-way T-valve and start the pump so that it is now sucking out of the bucket, through the filter and into the tank. But I just cannot find a 3-way T ball valve that isn't monstrously big and ugly, or very expensive. Big and ugly and not cheap: http://www.dixonvalve.com.au/dpl/dpl_page/2007/427.pdf Pretty, but not cheap. This is what I want. http://www.piping.georgfischer.com/stat ... 120C0932C3 Bob

Hi all, I need to replace a Sacem Pegasso2 external cannister filter. It's overkill for my 100L lightly planted freshwater tank (guppies, tetras, danios), but worked well and wasn't expensive ($80?). After 2 years it's now making lots of noise and I can't get parts. It's also a bit big and despite being pretty (gotta love the Italians) it's not quite the lounge decor I'd normally choose. My tank is small so I'd rather not clutter it with an internal filter, so I see my options as: 1) Buy another external filter off the shelf, or; 2) Buy a pump and make my own filters; I like messing around with stuff, so I favour the second option, but what are the risks? Can anyone recommend a silent pump (200 to 400L/hr) that's stay silent for years? This one is driving me up the wall. Bob

OT: 3 year old sandpaper When I was a three year old I drank nearly a whole bottle of pre-mix screwdirver (vodka and orange). It was orange and it was a drink, so it was orangedrink. This was one of many visits to the emergency department my parents made... but that's a whole 'nother 5 or 6 stories! I also 'replanted' our goldfish bowl with a 3 foot rubber plant. Between me and the neighbour's cat, those poor ol' goldfish sure had a hard time. I was always amazed at how well they recovered.

You could also buy one of those very sexy "Flavour Shakers" as seen on TV and used by Jamie Oliver. Buy one now for only 22 pounds and I'll throw in a set of steak knives!

Buy the "marble" it's not really marble. They are cheap as chips, last forever and are non-porous. But they are not very good for grinding, they are too slippery. You have to use them to crush. That's ok for pills, but lousy for a decent curry!

Hey it did it again! "Failed sending email :: PHP :: DEBUG MODE Line : 235 File : /home/fnzasor/public_html/fishroom2/includes/emailer.php"

Whoops. Some sort of error occurred during the post and so it has double posted. I blame technology, this wouldn't have happened with a pen and paper!

6500K seems to be the standard, but when I was reading up on it, a lot of shallow water plants actually prefer slightly lower, down to 5000K. I targetted 5500K for my shallow water swords and so forth. The general rule of thumb is the higher the Kelvin rating the bluer the light. Deep water fish and plants prefer blue, because that's what they've adapted to (the red gets filtered out by the depth of water). Shallow water plants prefer a bit more red. I'm not sure what the definition of "shallow" is, but light is noticeably blue after passing through 3m of pure water, so I guess about 1m can be called 'shallow'. Remember that this is dependent on their habitat, not necessarily your tank, but if you did have a very deep tank then it would not be advisable to plant shallow water plants and use a blue light! Also, light passing through different purities and 'types' of water will absorb differently, so the colour the plants see will depend on the type of water you have. ie. sea water is different to fresh.

6500K seems to be the standard, but when I was reading up on it, a lot of shallow water plants actually prefer slightly lower, down to 5000K. I targetted 5500K for my shallow water swords and so forth. The general rule of thumb is the higher the Kelvin rating the bluer the light. Deep water fish and plants prefer blue, because that's what they've adapted to (the red gets filtered out by the depth of water). Shallow water plants prefer a bit more red. I'm not sure what the definition of "shallow" is, but light is noticeably blue after passing through 3m of pure water, so I guess about 1m can be called 'shallow'. Remember that this is dependent on their habitat, not necessarily your tank, but if you did have a very deep tank then it would not be advisable to plant shallow water plants and use a blue light! Also, light passing through different purities and 'types' of water will absorb differently, so the colour the plants see will depend on the type of water you have. ie. sea water is different to fresh.

The first link took me to a 'fish highway' which is a very cool idea (as long as the perspex highway remains completely airtight. If it doesn't you get a really big mess!) The second (c/- Ira) took me to something different. That one has feeding ports below the waterline. Although the concept is the same there is a hell of a lot more to lose in the second one! Someone commented about "having some fun" and putting a straw in through the feeding port, but that wouldn't work would it? Even a siphon tube should get you nowhere.

Even you manage to get the bracing off (or fill the tank without bracing) I'd still keep that video rolling. Silicon has a tendancy to creep when put under load. You may be ok today, and maybe next month, but in a year it may suddenly let go. Glass can also break after being put under constant load for a long time. I assume yours is nice and thick. Any defects (scratches etc) also accelerate the failure.

I've got a black phantom tetra that I call Psycho. He's the sole survivor of a school and has been alone for nearly 2 years. He ignores every other fish in the tank, except 6 months ago we added 4 new tetra (exact species unknown, but look vaguely like Psycho, except they are not transparent and are now much bigger). Psycho has taken their presence as a personal insult and spends every hour of every day trying to intimidate the 'invadors' by fluffing, puffing, and eyeballing them. They just pretend he's not there! It's comical in the way they seem to deliberately avoid getting into a punch-up without actually acknowledging his existance. Especially now that they're twice his mass!

Tel, That's all very pratical and all, but it assumes that you are just measuring what happens to something you've already got. If you want to plan a cooled system then you need to step back and look at tank surface area, how big a fan to buy, how fast to run the fan, typical humidity etc. This is the Technical forum, not the Practical forum.