Dramatic change in tap pH

T

TomFromStLouis

I am a god to my angels
Feb 26, 2003
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St. Louis MO USA
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For some reason my tap water pH has gone from a very workable 7.2 to over 8.6. I noticed the change after seeing my fish respond unfavorably to a 50% water change. I checked pH and the tap water is off the charts! The test water turns a deep royal blue not even on my color chart.

I had let the tap run for some time (while pythoning out 20 gallons), so I do not think it was 'old pipe' water. Plus, the difference was noted yesterday and it persists today. The Missouri river just does not change that much. KH remains at 4. Any possible explanations? If this lasts a while, what will I do about my tank pH? All my fish and plants are meant for the water I started with!
 
Tom - STL county and city both use chloramines. There is always a little more ammonia left over in excess of the amount used to react with the chlorine. I tested water for AB for 11 years, and fresh out of the tap, it was sometimes 10. If you let it sit, it comes down prety quickly. I've found that as long as I do water changes of 40% or less, my tank buffers the incoming water. In the summer however (when they up the disinfection), it can be harder to do, and I've had to use pH down before.

With the recent rains, they may have upped their use of chemicals, especially if we're getting into a runoff situation. I've killed many a fish here with a pH shift, before I realized what was going on. The alternative to a buffer would be to let the water sit in a separate reservoir if you can. pH is the only parameter I ever check, since I discovered how wildly fluctuating we are.
hth
judy
 
WOW!

Is this a great place or what?

I put a call into the water company and they are processing a 'water quality complaint' which will net me a discussion with someone knowledgable within 3 days. The person who answered the phone did not even know what pH was...

Judy,

An awesome direct hit of an answer! In short, I will always need to monitor pH from the tap, right? And in trying to deal with my current green water issues, I probably should rely on frequent smaller changes so as to not shock the little piggies, I mean angels.

I DID notice that the tank pH settled down after a few hours. I may need the tap water pH to get back to reasonable level soon for a large water change and blackout.

Thanks for the informed responses.
 
I always check my incoming, and the tank periodically as the water goes in. (I fill with a hose, and add dechlor as I go). If I have to buffer, I do, but if I fill slowly enough, it usually takes care of itself. I also found that if I had an EXTREMELY dirty tank, and did TOO big a water change, the hit would be much worse, because I had knocked out my buffering capacity. ALL those years as a water chemist, and it took me so long to apply it to fish-keeping.

I take it you're on county if you're in Clayton? Do you know for sure you're coming off the Missouri? The city uses the Mississippi and MO, and combines them, depending on conditions. The county goes with the big muddy - out at Howard Bend - or the Meremac, in Sunset Hills, where all we have to worry about is chlordane ;)

Funny, the first boss I ever had, as a yet-to-graduate Chemist, now works for county water. If the name Elizabeth Ingles comes up, that's her. I know she's pretty high up in the lab.
judy

oh, and yes, this IS a great place:D
tanks!
 
Good point - if you want to pick your fish according to water chemistry, cichlids are for STL. I've never been able to keep guppies, or tetras, or a lot of other fish. And I stopped trying. I AM NOT buying a water softener or RO unit. And, I love my cichlids!
j
 
Tom, it sounds like they are adding quicklime to the water, to cut down on corrosion of the mains, and perhaps to "shock" some destructive thiobacilli. The quicklime is depleted in CO2, and your water arrives with that high pH as a result of CO2 depletion. Leave it in a bucket overnight with an aerator running in it, and see how that does for stabilizing pH.
 
Pretty sure we don't use quicklime here - there's enough scale built up in our distribution system as is. Our water's pretty high in calcium and alkalinity. We'll see what the ole water Co had to say.
 
what the water company said

Holy Alkaline Batman! Steve from Midamerican Water said they always send out water with a pH of 9.5 -10!

Now if I had known that when I began, maybe I would have a tank of cichlids instead of angels and tetras. <sigh> He was unable to explain how I measured 7.2 when I first filled the tank, or how I get a KH of 40 when he sends out 120. The high pH comes from adding Calcium Oxide to lower the hardness from 300 he says. I really doubt the building is treating the water in some way, but that is one of the few explanations he could suggest.

So it looks like I will have to season my water a bit (not easy in an office situation) or find some kind of pH Down chemical that will not screw everything else up (muriatic acid?). I still get a KH of 4 or 40 (wherever that decimal goes) and a current pH of 6.6 (thanks to the CO2), so my tank is right where I want it for now. But water changes will have to be smaller and more frequent to avoid stress. Any other ideas water gurus?
 
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