Mini-Bubble Fix

[GaryP]

My PanWorld return pump went out on me Thursday. As it turned out it just needed to be cleaned. When I installed it a few months ago a failed to install a threaded union for removal. Its in a pretty tight spot to start with. Anyway, a quick snip with some PVC cutters, a half gallon of vinegar, and a trip to Home Depot later and I had it out, cleaned, and put back in place with a threaded union.

I noticed a lot of bubbles after getting it running again but assumed it was from air in the lines being purged. It was close to the time when the lights went out that I got it back up and running. The next AM I still had bubbles.

I disconnected the union and wrapped the thread with teflon tape. That solved the problem.

I know several of you with new tanks have mentioned having problems with bubbles and was wondering if you had used teflon when installing the unions? It seems that I recall some discussion about whether the bubbles could be the result of pump cavitation. After this experience I think that these type of connections may be the main cause, although a leaking impellor housing is also very likely.

I used to do oilfield water chemistry and one of the things we sold was an oxygen scavenger to prevent corrosion. The first step was always to look for the source of the oxygen. Pumps and unions were always a good place to start. They can act just like a venturi.

Gary

[bprewit]

H2S and other compounds are rough on metal in the presence of oxygen! I work on disposal pumps and found that even the smallest opening can draw in oxygen. Most of the time you cannot see a leak of any sort, but once the pump is up and running it can start to draw in oxygen. Hey I also found that oilfield water chemistry places can hook you up with dissolved O2 test kits that read 0-100ppm of dissolved O2 for pretty cheap. The last I purchased was 50 tests for $20.

[GaryP]

Hey I also found that oilfield water chemistry places can hook you up with dissolved O2 test kits that read 0-100ppm of dissolved O2 for pretty cheap.

That's kinda weird, O2 is saturated in fresh, cold water at about 14 ppm. In salt water it is about half of that. I know which kits (HACH) you are talking about and don't recall what the range on them was. We were usually looking at O2 levels at less than 1 ppm in oilfield waters. We sold products (sulfite and bisulfite) that are chemically very similar to the dechlor compound (thiosulfate) we use in aquariums. I have an aquarium O2 test kit I bought years ago when I was having some problems with my first tank. Its not very accurate and its almost impossible to get a representative sample from an open system like an aquarium.

I wish I still had access to one of those Hach water analysis kits. They are so much better than even the best aquarium test kits, although I know that some of the reagents in the Seachem kits are made by Hach. The little foil packages are a Hach trademark.

I know all about H2S corrosion. I started off working on bactericides for sulfate reducing bacteria in oilfield waters in the early 80's. They are what cause the heavy pitting in steel that you probably see a lot of in the Permian Basin. They are similar to the bacteria that produce H2S in DSB in aquariums. I do think a lot the H2S people smell in a DSB is really organic mercaptans (the stuff they use to odorize natural gas with) that is a natural result of biological decay of proteins. I have seen what looks like Iron Sulfide in my own DSB when I moved it, but that could be iron salts of mercaptans as well.

OK, I'm probably way over a lot of people's heads so I'll shut up now.

Gary

[bprewit]

<organic mercaptans (the stuff they use to odorize natural gas with>

I worked at a small gas plant years ago as a roustabout and we would empty 55g drums of mercaptan into the propane loading station. If you stood downwind when the drum was pouring into the vessel, you would smell like that crap for about a week. Nasty stuff!
I have two test kits, one reads in ppb and the other in ppm. I dont know if most people are worried about the dissolved O2 content in their tanks but they are **** good test kits, easy to use and pretty reasonably priced compared to all the other test kits out there and very accurate.