I'm just putting this out there for all to take note of -

I have been having problems with higher than usual pH problems in my community tank (Juwel 180l), which occasionally jumps from 7.0 to 7.4+ due to what i think may be the local Wellington water supply. After talking to a couple of staff members at LFS i thought i would try Aqua One pH Down -

http://www.aquaone.net.nz/cart_product19299-1-2881.html?Title=92084%20AQUA%20ONE%20PH%20DOWN%20QUICK%20DROP%20100G

Used it as directed after weekly water changes for the last 3 weeks, then started to lose fish last week at an alarming rate of one a day . Did a quick check of all the usual levels - pH was fine and sitting at 6.8/7.0, Nitrates and Nitrites were fine at 0 or close to it, Ammonia was fine at 0, but Phosphates were alarmingly high at 10 (3 months ago it was at 0).

I tested my source tap water before and after adding Aqua Plus Water Conditioner and everything looked fine (pH a little high at 7.2 but basically ok, Phosphates at 0).

HOWEVER..... when i tested a cupful of the conditioned water with a tiny bit of Aqua One pH Down added (1/4 of a scoopful using the scoop that comes in the container) the Phosphate level jumped through the roof to 10. The Phosphate spike may not be the cause of the fish deaths, but it seems a bit too coincidental that they only started to happen with introduction of the pH Down.

I now have to slowly flush the Phosphate levels out by doing large water changes (about 40-50%) every 2 or 3 days, and hope like hell i don't lose any more of my little guys.

So just be careful if anyone out there is using Aqua One pH Down or considering using it.

thanks for sharing.

it is always a big risk to start adjusting water parameters chemically IMO. it is too easy to get it wrong and have it swing drastically and i think this is another vote for not using products like ph up/down or similar options. there are safer options like using driftwood or shells and marble to buffer the water which will cause a lot less stress to all.

thanks for sharing.

it is always a big risk to start adjusting water parameters chemically IMO. it is too easy to get it wrong and have it swing drastically and i think this is another vote for not using products like ph up/down or similar options. there are safer options like using driftwood or shells and marble to buffer the water which will cause a lot less stress to all.

A list of safer (or natural) options to use instead of chemical for any reason would be good.

wood will lower ph

things like shells, coral, crushed marble and lime stone will raise ph. they are the only items i have used but they work well.

I wonder if it is actually pH swings that killed the fish, not the phosphate. Depending on buffers in the tank, adding chemicals like pH Up or Down will alter the pH quickly but then it may swing back just as quickly depending on the buffering, or lack thereof. As pH is logarithmic, a small change can make a big difference. My tap water is high in phosphates (can't remember what as it has been a long time since I tested it and no longer have a test kit but it was way higher than 10) and it does not kill fish but swings in pH can do so.

Since there is nothing wrong with 7 - 7.4 for many fish, why were you trying to lower it? If you need lower for breeding purposes then rain water is good.

i don't think it was the ph swinging that was the issue, that's just the most common problem i hear of from people using the ph adjusters.

it is always a big risk to start adjusting water parameters chemically IMO

Agreed, it is also a big risk trying to adjust your pH by any means with out knowing about the hardness of your water.

just to let you know the PH down is actually phosphoric acid, so it does give you false high phosphate readings, it is harmless to the fish if used correctly (although you will never get and accurate phosphate reading again)

+1 on the pH swings being the killer.

Phosphoic acid does not give false phosphate readings it gives actual phoshate readings. It makes the hydrogen ion available (to lower the pH) and forms phosphate. If you were to feel it was absolutely required to adjust the pH down you would be better to use dilute hydrochloric acid. A pH of 6.8 or 7.2 will not kill fish but an instantaneous change might. It certainly would not be good for fish.

It's possible you got very small areas of very local low pH after adding the pH-down that were 1 or 2 points lower than the average. If the fish swam through this it could damage the gills. After a time this will mix in and average out to the pH you measured. If you are going to add products to adjust pH you need to remove several litres of tank water, mix the pH modifying product into this to seriously dilute it then very slowly dribble it back into the tank over about 30 minutes and it must be added to an area of high-flow to force it to be distributed evenly. Dripping the pH-down product directly into the tank will create small areas of concentrated low pH until it has time to properly mix in. As fish are naturally inquisitive they will often swim over near your hand where you are adding the drops - bad news...

Thanks for your comments Alan and Warren. I had actually dissolved it in a cupful of water during water change and poured it direct into the filter container so that it would be force-dispersed into the tank. But i suspect that despite not using a large amount of the stuff, over 3-4 weeks it had a cumulative effect.

I have now done 3 large-ish water changes, and the Phosphate levels are slowly coming down (now at 5 instead of 10). Going to persist with large water changes for a couple more weeks, and have tossed the pH Down in the trash.

:facepalm:

the reason I said "false" phosphate readings was because it doesn't tend to increase algae growth like regular phosphate readings.

imo its more important to provide STABLE pH than exact pH, most fish nowdays are tank bred and are not as fussy about pH as wild fish, I have heard of commercial breeders (in asia) doing discus in 7.8

p.s. don't throw it out, its brilliant at cleaning cutlery and copper.....

Phosphate is phosphate and it doesn't matter where it comes from. It is a bit like paying extra for organic salt. It is the ratio of phosphate to nitrate that is the problem. With good light, CO2 and and adding ferts there can be quite a bit of both without algae problems. It is the balance.

is phosphate really phosphate???.......

chemically what is called phosphate is a rather large group of chemicals (the acids are just a part of it) the tests only tell you if the there is any P ions floating around....

just to confuse you....http://en.wikipedia.org/wiki/Phosphoric_acids_and_phosphates

It is the "P" in its various forms that the plants and algae use to build proteins. Problems with algae are usually caused by an imbalance of "P" and "N." This imbalance can be fixed by adding more "N" provided there is enough "C" and enough light.

The point was that rapid pH swings are more dangerous to fish usually than pH itself and pH down may well cause algae problems.