Warren

Putting Rocks in the tank will not reduce the water pressure. The pressure on the side glass will still be exactly the same, but the force or effective pressure will increase on the bottom glass. If a very thick base is used, the glass will not need to be thicker than the sides. The base will need to be very flat and level however. Based of the glass thickness calculator http://www.fnzas.org.nz/glassthickness.0.html you need 17.09mm thick glass to get a good safety factor. If you use 10mm glass, there will only be 30% spare safety margin. Even the smallest assembly error will cause it to break. It will need bracing along the bottom edge and full length top bracing. I would seriously advise against 10mm glass for a 750mm tall tank. My tank was 950mm in the viewing window and I used 19mm glass. The calculator said I should use 25mm but I could not find any. At 19mm it still had 225% safety margin. If you use 10mm you will only have 130% margin, way too small. Even 12mm glass will be pushing it as there will be only 187% margin. 15mm glass however would most probably be ok as there is 292% margin. If you lower the height to 600mm you will be ok. So the long and short of it, no 10mm glass is not ok for 750mm. 15mm is probably ok.

If you are worried about electrical noise as mentioned by John, it is a simple procedure to replace the first two op-amp stages with a precision instrumentation op-amp. These devices have programmable gain and offset adjustment. Both the Gain and Offset are temperature stabilised also. They are a little pricey, but are worth it. The differential input stage if designed correctly will allow enough common-mode range to stop any noise effecting the reading. There is also no low-pass filter section to remove any high frequency noise. There is an optional cap 'You may need a cap here, I didn't' that is supposed to serve as a low pass filter, but is more likely to make the output of the opamp unstable to high frequencies. While the circuit is fairly good for how basic it is, there are many improvement that could be made to make it more temperature stable and have less drift as it ages. Also, to use CO2 injection with pH controllers controlling the CO2 delivery you must have the correct KH. The KH/CO2 balance is what sets the pH in this type of setup. If your KH drops then the controller will put in less CO2. If the KH goes up (maybe during water change) then more CO2 will be added to pull the pH down. It is possible to add too much CO2 if the KH is unstable. pH probes usually need regular cleaning when used permanently in aquariums. Proteins stick to the probe slowy making the reading go up and therefore the CO2 go up. If the probe gets too blocked with protien, you can poison (suffocate) all your fish with CO2. After cleaning it may take several hours for the pH probe to stabilise back to the correct reading. I looked seriously at pH controlled CO2 but decided against it due to the risk involved. I didn't want to lose all my Discus due to a controller / probe stuff-up. I use a timer controlled solenoid, needle valve and gas reactor in the filter return. It has been working fine for over 6 years now and has never once missed a beat. It never needs maintenance (except filling the CO2) . You also don't have to worry about the KH or pH. The pH fluctuates less than 0.25 in a 24 hour cycle so is ok. The CO2 is added in sufficient quantity to make the plant grow really well. If you insist on an automatic system, don't skim on anything. Use the best temperature and age stabilised components you can get (both op-amps and voltage references). Find a really good quality probe (it will cost $200-250 for a good one).

A conductivity meter actually measures the amount of the total dissolved solids (TDS) in the water. This means any dissolved substance, not just Iron and Heavy Metals. It is only a guide as to how pure the water is. It cannot tell you what is in the water. Dissolving salt (NaCl) into water will raise its conductivity. Add more salt, more conductive. Pure water is a pretty good insulator and therefore shows no uS.

I don't have the ballasts etc inside the hood. Only the tube is inside mounted on a fitting shaped like a tombstone (in fact this is what they are often called at the wholesaler). I once made a hood only 65mm thick using these fittings. I normally gut the fluro fitting for the parts. It is sometimes cheaper to buy the whole fitting than the seperate parts if there is a 'special' on fittings. The tombstones only cost about $1.00 each. There are several different styles to suit different mounting methods.

Go certral filtration. If you have a UV steriliser it makes it a lot safer. Dump the RCD. I know its good for safety, but if there is a power cut and your are out, the RCD will trip and there will be no more power until you reset it. Instead, put all your heaters and pumps into one sump. Into the sump put a reasonable sized stainless steel plate connected to earth. If anything goes wrong with a heater or pump it will trip the circuit breaker instead. Good, reliable and safe! Its what I've done, and I even tested it to make sure it works by breaking the glass on and old heater that was stuck on with a plastic pipe. There was a bit of fizzing and sizzling for about 1-2 seconds and then the 10A breaker tripped. I had a probe in one of the tanks at the time connected to a Digital Volt Meter on peak hold on the AC current range (measured between probe and earth). It peaked at 0.6mA. You would feel this, but thats all. Its certainly not going to kill you, just give you a little tickle. By comparison, an earth leakage breaker will not trip until 15 or 30mA depending on the type. This will just about throw you across the room.

Never said they were either!!!!!!!!!!!!!!!!!!!

Read Glass Thickness Article. http://www.fnzas.org.nz/glassthickness.0.html Good to make glass thick enough so no-break!! Also tell how to join glass proper so no let-go!! Now no problem for earthquake!!! Ooh, is stand strong for earthquake?? Hmm...

The original post states that approx 50% of bacteria are removed. What everyone seems to have missed is that not all bacteria are the same size. It is quite possible that the bacteria that cause the medical problems are fairly large and get trapped by the silk. The smaller bacteria get through but are either harmless or the people are immune to their effect. You can cold sterilise water if it is passed through a 0.25 micron or smaller mechanical filter. No bactria can pass through this size hole. A filter of this size will very quickly clog up if used in and aquarium. I use 15 micron filters on all my tanks. They do not stop bacteria getting through, but remove all particles from the water leaving it 100% optically clear.

Why do you need waterproof ones?? I use standard fittings on all my fluro's. My 8' tanks has 8 fluro's in it and no special precautions for waterproofing the tubes. I do have covers on the tank however. This stops vitually all evaporation and stops any condensation on the inside of the hood. With that many fluro's, the hood is fan cooled anyway so there could be no condensation. If you have good enough covers on your tanks you don't need special fittings. If you buy a complete unit from your LFS you will likely pay over $100 for a dual 5' and more for one with waterproof fittings. You can pick one up from the local wholesaler for approx $40.00 including tubes!

Check your nitrate level also. If it is over 60ppm then the pH could be due to a high level of nitric acid in the tank. Using Backing Soda is the easiest method to raise pH. You can go a whole point if the Backing Soda is introduced very slowly. For 160L you should need about 1/2 teaspoon to raise your pH from 6.0 to 7.0. Mix the backing soda in about 1L of tapwater. Add a lit bit at a time over a 1-2 hour period. You will still need to find out what is causing the pH drop however. How often do you normally do water changes, and how much? Do you have undergravel and vacuum regularly?

Bah, I'll feed them out for you. Many of my fish love to munch live food. Its really good for making them breed.

Sounds more aggressive than an oscar. I've always been able to lift my oscars out of the tank by hand. They are the most placid fish I've ever seen, oh, except when they are breeding, then they try to tear your hand off.

If you want to breed Guppies, just get hold of some males and females, put them in a tank, add plants and within weeks you will have lots. You could probably get them to breed in an old bucket, its simple, get guppies, add water, mix and presto, baby guppies!

If you can get them at trade with a bit of discount, they should be about $4.50-5.00 each for TLD86 and $20.00-22.00 for TLD96. If you have to buy them retail, you'll pay about $11.00-12.00 each for TLD86 and about $38.00-40.00 each for TLD96. The TLD96 is much better and I've found it to be better for plant growth than any top-dollar pet shop tube available readily in NZ. If you look at the specs for top-quality aquarium tubes, they are very similar to the TLD86 and TLD96. The TLD96 has a broader spectrum and higher lumens per watt however. The TLD86 is about the same quality as a good aquarium tube.

The Philips TLD86 and TLD96 are both 6500K daylight tubes. They are very white in colour and also very intense when you look directly at the tube. They have a higher lumens per what than most other standard 58W tubes also. If you only want to use 1 type, I've found it to be the best. You get a white daylight colour and excellent plant growth.

Pet shops are way more expensive if you know where to shop and have access to lighting at trade prices. I've seen Triton 5' 58W daylight tubes for sale in pet shops for $60-75 each. While some people are failry happy to pay this amount, I'm not. For non-planted tanks I use Philips or Sylvania TLD86 lamps at about $4.50 each and for planted tanks I use Philips TLD96 at about $20.00 each. The TLD96 is a full spectrum 6500K daylight tube with very high colour rendering capabilities. It makes my plants grow very well (100mm / day on Cabomba and 1 full sized new leaf every 2 days on Echinodorus osiris). Its best to shop around. Pet shops have to make a buck too at the end of the day, but keep in mind, buying retail and through a chain that has many more resellers in the link will enevitably push the price up. If you can access trade + discount through a friend or relation it is certainly worth it. I'm lucky to be in the electrical / electronics industry so have easy access to these items at good prices. That why I don't mind replacing the 8 x 58W fluro's on my planted tank every 6 months. I suggest you try somewhere like Mastertrade (if there is one in your area) and try to find someone who can get the lights at trade price.

For what they are worth, may I quickly make reference again to some articles I've previously written: http://www.fnzas.org.nz/filtration.0.html http://www.fnzas.org.nz/filtration-2.0.html http://www.fnzas.org.nz/filtration-3.0.html http://www.fnzas.org.nz/aquarium-conditions.0.html These should help most people who are unsure about filtration and hourly turnover.

Good reply Paul, I was going to also suggest checking the Latin name. Many times a common names exist for a bunch of different plants that have no relation to each other. Amazon sword is a clissic example. There are at least 5 different species sold as Amazon swords. They all look vaugely similar when small (shop sized), but look very different as adult plants.

I'd read that Oto's are ok in low temps (18-22'C) and don't actually like warm temps above 25'C. I bought 2 dozen once for my planted tropical tank running at 27-28'C. They all slowly died over about 2 months. May have been something other than the temp, but I couldn't think what.

Just like eating a Flake too, - YUM YUM!!

YUM YUM, I love swiss cheese!!

Come on now, you're a woman, - you'll have at least 20 pairs!!

I've got lots of holes I hole-sawed into my landlords floor. I kept all the plugs so I can epoxy them back in when I leave. The carpet is nylon, so it just cut with a knife and folded back. Once the plug is replaced and the carpet is glued back down, you'd never know there was a hole. All my inside tanks had holes through the floor, - it made water changes easy. The waste went down one pipe and an outside storage drum + pump came back to fill the tank on another. Good system as long as you didn't get sidetracked. Set the filler running once and started typing away here in the fishroom. A long time later and oops, very wet lounge floor. I now have an overflow alarm so as long as I'm here while the tanks are filling, I'll know if I've forgotten to turn off the pump.

Where do you put the shoes??

Yes, quite a bit bigger, a lot newer and doesn't look like a ****-hole.