Philip

Fantastic information and helpful photos. Thank you very much. I'll get the magnifying glass out and get to work. R/ P.

I would take a sample to someone else, like your local fish store and see what they get. If I had to guess I'd say your test strips have reached their expiration date. One thing I will say, as a chemist, the Aquarium Co-op test strips that I have used have been dead on, and I spot check them against expensive equipment that I use in a lab. Good luck,

xXInkedPhoenixX Now that you mention it, it is happing most early in the morning. I highly doubt any eggs would survive in that tank, but it is heavily planted. Is there anything in particular I should look for?

I've kept Otocinclus for decades and they have alway hung out together and generally moved around as a group, but lately I have about 7 of them that are acting like I've never seen. It might not be exactly schooling behavior, more shoaling, but they keep in a very tight group and move everywhere very quickly and in tight group. Up and down the entire height of the tank and back and forth across the whole tank. It's kind of cool. They used to be content to hang out in a spot for hours but now they are all full of energy. Nothing has changed, they are all happy and healthy. Big fat bellies. I suppose it should be something to enjoy and think things change once in awhile, but it seems so strange to me. Could this be breeding behavior? Or possibly something is stressing them out?

I have a general question when it comes to CPD breeding. Are the adults more prone to eat the eggs or the newly hatched fry. The reason for asking is because I'm trying to decide on a setup for breeding. If the eggs are more at risk, I'm thinking I need to get the adults out of the tank, or collect the eggs, as soon as possible. If the fry are more at risk, I can leave the adults in the tank longer and therefore allow them to drop more eggs. Just guessing, but I imagine they are both at risk, but I'd like to know what the best course of action to take from someone with actual experience. Thank you in advance.

I'm sure you are in the ballpark. I'm hesitant to chime in when I'm using a $1,700 pH meter and don't want to come off sounding like other people are wrong. We are talking about being accurate to .002 which is absurd in the fish hobby. When it comes to what we do with aquariums, we just need to be able to troubleshoot or know we are fine. If you want to know exact numbers it will cost you big bucks, and is unnecessary. It's also why I'm a fan of the test strips. Fast, easy and pretty reliable. Can't beat that.

Sir, I use a Hach 411d, calibrated daily. Maybe I misread your results but I thought you got 7.8 and the sample you brought in was 7.75. This is about the difference you get with CO2 absorption. Not just from adding CO2 to your tank, which you would see locally, but from air in the sample. Note that it will not change a lot. You won't go from 7.8 to 6.5 for example, but the amount you got is reasonable. You are correct about your assumptions with pH. I have said in the past, and I believe Cory has said similar, but you really can't look at something like pH on it's own and make broad assumptions. You really need to take it in context with all your other parameters. I believe your thinking is on the right track, but don't put too much stock in one thing or one reading. Look at it as a whole.

Not to get too geeky, but wet chemistry is notorious for skewed results. pH meters drift and should be calibrated often. I like to test buffers to check accuracy and even titrate using phenophthalein so I know exactly where 8.3 is. I would totally trust that for comparison to make sure my meters are spot on. Keep in mind that I am a water chemist and have very high end bench meters and spectrophotometers. The cheap meters most people have are pretty good, but I wouldn't go to the bank on them. For those taking their water to the fish store, or University in this case, you are very prone to CO2 absorption because of time and how the sample is usually stored, so I wouldn't trust their pH readings. The variance you got can easily be explained by that. Both can be right. Fill bottle all the way with no air trapped. Minimize time in-between. It's best to read pH right away, expect it to go down a little over time. Also, if you have lower conductivity water, where there is little buffer, some of these results, especially pH can swing. If I were a betting man I'd say the test strips are more reliable. Sorry so long.

Anything which there is oxidation taking place there will be a gain of oxygen, but that doesn't necessarily mean you will gain O2 in the form of free oxygen gas. You may have 3CO absorb the O2 and become 3CO2. I think the point of the original question was asking if some reactions resulted in more O2 in an aquarium. The answer is probably yes with most of these examples, but not enough to really matter. At least in the long term balance of the aquarium.

So true and not just for Chemistry, but for life in general.

I have always had great luck with most frozen foods like beef heart and bloodworms. Best results are with a floating strainer to drop the cube in. Also I feed chopped up red worms I raise and some pellet. They seem to love everything. No experience seeing them feed on the bottom. On a related note, if you want to see a larger Cichlid go nuts, feed them whole red worms. They suck them in so fast that worm is probably wondering where the heck he is way before he realizes it's too late.

Exactly. In your example you are more often than not getting incomplete combustion, resulting in CO. In most cases you want extra O2 to make sure you are using up all the carbon. The reactions are not really complex nor unexpected, it's just so many different things going on at once it's hard to simplify.

That will work, especially on suspended solids that settle out. However it will promote a certain amount of biofilm. A slime that bacteria produce to protect themselves. Whether that slime will slough off or you will have to go after it mechanically or chemically will have to be seen. In the long run I think you guys have a good plan and are testing out methods that should be very helpful to the hobby in the future. Thanks.

Hobbit, I have not had any in a year as I redo my fish room. Only a few tanks right now. I raised the flightless ones Drosophila melanogaster and also the hydei. Depends on the size of your fish. The melanogaster are pretty small. Don't let the fact that they can't fly fool you, they are lightning fast and if you are not accustomed to handling them, when you open the lid they will get everywhere. A little shaky-shaky on the surface of the water and it's amazing. The maggots are also a very tasty treat. For the fish, not me.

You might. But for now nothing gets by my first line of defenses until I decide. All it will take is one to sneak in and I'll be picking snails for the next four months. It would have to be one that I can have neutered or is celibate.