lduncan

Playing with fire there Caryl I've got some topics which might be interesting: How the nitrogen cycle REALLY works. Alkalinity Myths and misconceptions. Corals, lighting and nutrients. Polyp responses and triggers. Coral and their symbiots, who's wearing the pants? UV, more that just a killing machine.

You know I don't think the issue is whether fish are getting overfed, it's more how much food your tank can handled without nutrients becoming a problem. There is nothing wrong with dumping a boat load of food in, so long as you have the ability to get the majority of the uneaten stuff out before it becomes a problem. The dangerous thing is letting food sit and rot. That's when the nutrients become an issue. I think that a lot of people don't fed enough. I also think it's a bit strange when people stop feeding to try and control nutrient problems. The problem isn't that your feeding too much, it's that your system is not removing enough crap fast enough. Layton

Yip, carbon, nitrogen, phosphorous ratio (106:16:1). Known as the Redfield ratio. Redfield did research in the 60's on the ratio of these elements in phytoplakton, and their relation to seawater levels and primary production. Often in aquaria nitrogen and phosphorous are available well in excess of carbon. Alkalinity is one of the biggest, and one of the most efficient sources of carbon. Layton

Very good idea. It's related. You can skew the balance of power to different types of bacteria by altering C:N: P ratios. Meaning that the cyanos are disadvantaged, while other no so "visible" bacteria are advantaged. Layton

Probably because it kills bacteria. Something you don't really want to do. I've noticed that it often forms on piles of detritus. Get rid of the detritus -> no more cyano. Basically just keep the tank clean, alkalinity up, blow the crap out from the rocks, and make sure your skimmer's up to the job.

You know wasp you are really misleading with the way you chose to quote stuff. Here is the full meaning of chimera's point: In particular the last part about understanding how it works. You don't have to physically use something to understand how it works. Do you have to be hit by a bus to know how that works? Comes back to the whole limitation of experience thing. What you've said previously is quite different, and implies that people can only learn through experience. That is just wrong. Layton

Wasp, I think you missed it again. I don't care whether you use the calculator or not. But when someone says they don't trust it, maybe it would be useful if they know what it's doing in the background. It's not being arrogant, like you suggest. Also I don't really get your point above. A calculator is not going to adjust for ignorance, and neither is trial and error. If anything, a calculator is more useful in detecting this sorts of things, because you know how much you need to add to get to a certain number, and if it doesn't get anywhere near that number, then you know to do some deeper investigating of other parameters. What would happen if you were just doing the add some and test, add some and test, feedback method? You'd keeping adding more, until you found it suspicious, at which point you may have added far more than you should have. Layton

wasp?? Sure the horse has bolted if you've already spent the time on a trial and error type method. But if you haven't, why wouldn't you use the calculator? It sure does make thing easier. How would you do this without a calculator? Layton

You can spin it which ever way you want. But the fact is, give the calculator accurate info, it'll give you an accurate answer. You can just chuck some in hoping it's close to required amount then test, find it's just right, nowhere near, or way too much, then adjust and test. Or you could test then put some numbers in the calculator and come up with the number of grams you need to add within +/- 5 or 10%. Then add that quantity over whatever period you want. Why wouldn't you use the calculator? Surely it just makes things easy? Maybe a rundown of what it's working out would be useful? Layton

My guess would be the mushrooms. They are probably one of the most lethal corals, they'll maim almost any coral they touch. LPS are also prone to bacterial infections / BJ disease if the water quality is poor. Layton

So you use trial and error effectively to work out how much you need to add to raise something a particular ppm? The calculator does this without trial and error, and is more trustworthy. Why is it more trustworthy? Because the chemistry of what's going on doesn't change ;-) Atoms are atoms. The calculator is always right. If you want to know how it works, i'll run you through the calculations it's doing, then you might trust it? Layton

UV and copper? I don't think that's a good idea. I've never used copper, however, I think many copper based medications are organic chelates of copper. If you zap that with UV more than likely you are going to break those bonds. There is obviously a reason why they are chelated, and not just copper salts, so best to use one or the other.

Corals are no problem. They are pretty hardy, and will happily live with (and use) ammonia. It's fish that can be the problem, they don't like ammonia.

Well a pH probe works like all other ISE's. It's an ISE which is sensitive to H+ ions, so you need to have some sort of semi-permiable membrane. They basically operate like a battery. You have two electrochemical half cells. One electrode is called the reference, which is a tube filled with potassium chloride with a silver wire in it, and a porous end which comes into contact with the test solution. The second is called the measurement electrode, which is a silver/silver chloride wire in a potassium chloride solution, held in tube made of lithium doped glass (this glass acts as the selective membrane for H+ ions). The potential difference (voltage) is measured between the two half cells, and that corresponds to the concentration of H+ ions (pH). Most pH probes are combination probes which means they house the two half cells in a single "stick". The probes are something you buy. You can't really make them. The meter on the other hand is relatively easy to design and build. Layton

Yip, cause 0.02 ppm phosphate is high for these animals. And that's just the phosphate you can measure, there are other forms, and sources other than the water column for nutrients. Layton

You bring up a good point. Sure some types of corals can tolerate those conditions. However I guess the question is do these corals thrive because of the algae, or in spite of it? Is it just convenience that the conditions required to keep some algae going are the same which provide something that these types of corals need to do well? As for releasing substances back. Algae leak DOC, some species up to 10% of their biomass (Spotte). They can produce significant quantities phenols and alkaliods. Especially the caulerpa species of macro algaes. These compounds are generally not good, some are just outright toxic. As for coral reefs being algae reefs, remember there are a lot of different types of algae; Phyto, zooxanthellae, macros, micros, corallines, etc. So that sure there may be a lot of algae on a reef, however again, are the corals there living happily side by side with the algae, or are they there in spite of the algae? (The algae I've been referring to are the typical macro algaes you see in the hobby) Layton

No problem. A pH probe wouldn't be too expensive. Using a high input impedance opamp buffer. Fed to a ADC on a micro would work. Standard pH probes typically output a voltage of 0v at a pH of 7 then 58mV per decade (for each pH point) in either direction (positive and negative). The probe pretty much acts as a high output impeadance voltage source with output varying between -406mV to +406mV

You mean the fact that one of the pioneers and biggest promoter of the turf scrubber "natural" filtration couldn't get it to work successfully on several high profile public aquariums including the GBR aquarium?

Not really. The more expensive devices use a component call an ISFET Ion Selective Field Effect Transistor. It's a pretty interesting component. But I doubt you can buy them as a discrete component, and the circuitry required to drive them needs to be fairly sensitive from what i've seen. The key component to almost any ion sensor is the production of a semi permeable polymer membrane. They allow the ion you want to measure pass through and exclude all others. This causes a charge to build up on the other side of the membrane which can then be sensed by the gate of the ISFET, allowing current proportional to the concentration to flow. These polymers I believe are the expensive part. I don't think it's something you can DIY, or do inexpensively. Layton

It's not hard. But it will be expensive. ISE's (Ion Selective Electrode) are what you're looking for. They are similar to pH probes. You also need to watch out for interference ions. They range in price from about USD $200 for the cheapest ones, up to thousands of dollars for higher quality ones. They also vary slightly depending on the ion you need to monitor. Layton

Here are some things to think about: First is the issue of how much and what waste they actually remove, then what form that waste needs to be in to be used by them. Also consider the conditions they need to grow, and absorb these nutrient. If they're not growing, they are not taking up nutrients. They require a dirty environment (relative to the conditions you're trying to achieve) to grow. So while you're trying to create a low nutrient environment by growing stuff which requires a dirty environment. Finally, these are living organisms, and as such they produce waste. What effect does this have on the animals you are keeping. There are often pitfalls of using living things (whether plants or animals) to reduce nutrients. Layton

What types are beneficial? Well for they types of animals almost everyone keeps, none. What's available? There are a few, which probably shouldn't be named on a public forum. They are illegal, and some are highly invasive. Layton

Looking good Tim, I'm gonna have to get a frag of that stag ;-) The trigger looks great. When are you back Steve? Must be soon? Layton

Large format inkjet printers such as this: http://www.epson.com/cgi-bin/Store/Wide ... oid=-12805 Layton