There's no way that that amount of vinegar would hurt your guppies. I calculated a 1: 10,000 dilution. Vinegar is an acidic organic that is easily decomposed once diluted in water.

 

Thank you for your answer!

I found that this method works quickly for me to clean the glass, but I was always a little bit worried about the vinegar that unavoidably gets into the water column. Its good to know that this small amount (< 1:10 000) is rally not that bad. (I guess it also helps that it is hard water and lots of plants?)

 

I'm going to try vinegar next time I clean tank rims.

 

I put a little bit of vinegar on a soft scrub sponge and I use that to loosen up and remove the hard water marks when water level is lowered in the tank. I try to avoid vinegar to get into the water as much as possible, but obviously some will get into the water. I use gloves so that my hand will not smell vinegar .

This is a hard water NPT tank with endler guppies in it. I have not seen any problem yet using this method. But your tank and inhabitants may be very different, so just be super careful and try it on your own risk only

 

If you have one of those magnetic scrubbers (magnafloat) you can use an eye dropper to apply the vinegar. Flow the vinegar out along the top inside edge of the scrubber so that it gets between the coarse bristles and the inside glass. That way it doesn't get on your hands.

Capilary action seems to keep enough of it between the bristles, instead of just flowing on down, but I don't guarantee that this technique gets less vinegar into the tank. It's just easier.

 

I guess it depends on the type of vinegar, lol. I am old school (the Dr. Innes books as a child - if one every gets to a book store with older books, or online at Amazon or Ebay well worth the look. Things, such as a natural tank that are considered "new" were common then, no filters or even air pumps as their are now.) and don't do any cleaning with any living species in it. Here is a great article, note a certain type (pure white) can be used for adjustments to change of PH.

What I note is the high evaporation rate and hence the build up of mineral deposits, which means that your mineral content of the water can be changing over time (unless you are taking some water out - from the bottom so you can get some muck out as well, and slowly dribbling fresh adjusted for PH, and temperature (can do others as well such as mineral composition, back in).

https://www.sapling.com/5421819/can-vinegar-used-fish-aquarium

"Distilled white vinegar is best for use with fish aquariums. Wine vinegar and apple cider vinegar can contain other organic materials that could be harmful to aquarium fish."

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If you drain some water out and then retop it - this should not be an issue. But many just top off evaporating water not realizing these minerals can build up. Like lakes no outlet (Salt Lake for one and others in Africa), most have fresh water in and river-lets, streams running out. So an aquarium is like a lake with no outlet for these buildups.

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My books are long stored so here is a quick search for the gH, KH tests.

"I would test for are gH and kH, or General Hardness (amount of total dissolved minerals) and Carbonate Hardness (the amount of dissolved carbonates, which are also your pH buffers). The kH is not as important right now, but you do want it reasonably low or you'll never get your pH to raise or lower. But if your gH or general hardness is high, as I suspect it will be, then you can definitely count on lots of dissolved minerals, including probably the iron/rust you're seeing."

Best to you...

 

I guess it depends on the type of vinegar.
"Distilled white vinegar is best for use with fish aquariums. Wine vinegar and apple cider vinegar can contain other organic materials that could be harmful to aquarium fish."

In general, anything that is safe for humans is safe for fish. A 1:10,000 dilution of red wine vinegar or apple cider vinegar is not going to kill any fish. A more robust vinegar may have a few more organics than distilled white vinegar, but then an NPT is filled with organics. The decomposition of those organics will just provide plants with more CO2. It's all good!

 

Hi Sherry -- GH hardness is a measure of divalent (+2) cations only - mainly calcium and magnesium (not total dissolved minerals). You can add heaps of Na+, K+, Cl-, SO4-, CO3-, NO3-, etc and they won't raise GH measurement. Regarding KH (alkalinity or carbonate hardness) why do you "want it reasonably low or you'll never get your pH to raise or lower". Isn't stable pH the goal in most cases? For specialty fish that really need low pH, then low KH is the goal, but for most plants and fish that are not blackwater-dependent species, moderate KH is helpful, isn't it?

Been a few years since our Anubias Design Yahoo Group days ... hope you're well.