Question Regarding Tap Water And Water Changes

JaredK511

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Hello all,

New to these forums but I've been keeping fish for over 10 years to great success. I'm very diligent about doing water changes and keeping my water quality very high for my fish but I've recently come into what seems to be a reoccurring issue.

I moved to a new apartment about 2 months ago and I'm convinced there's something up with my tap water. I live in Southern California and I know the water is very hard here (every time I take a shower my skin always feels drier than when I came in). 2 weeks ago I did a 50% water change on my 10 gallon and 5 mins later I noticed all my fish were dying or about to die as they were swimming erratically and gasping for air/turning pale. That turned out to be chlorine poisoning as I did not add enough Prime to the tap which came out of my bathroom faucet. The water company had done some maintenance which I guess caused the chlorine levels to be higher than usual. Since then I've dosed Prime even higher than usual just to be safe.

Today I did a 50% water change on my planted 6 gallon cube and 5 mins later I noticed my 7 Galaxy Rasboras were all at the top struggling for air. I immediately added more Prime but that didn't seem to help so I figured it must be a huge pH swing. I removed the new clean water and added the older water back to the tank. Within a few minutes my fish luckily went back to a normal state, swimming and breathing without struggling. This water change only seemed to negatively affect my Galaxy Rasboras but not my Scarlet Badis who is the only other inhabitant in the tank. Could it be there's a huge pH difference between my tap and older, settled tank water which is causing harm to my fish (at least the ones that are more sensitive to water parameter changes)? All my tanks are fully planted with driftwood and Almond Leaves to lower the pH so I know the tank water is softer than the tap. But would a large water change cause such a swing that would affect the fish? I've never had issues before doing weekly 50% water changes. In fact the fish love it and become livelier.

I've been doing much smaller changes recently since my last incident and everything has been fine until today when I did one larger one on just that one tank. (I didn't even clean the other tanks today because I'm nervous they'll be negatively affected as well).

Should I call my local water company and request a report of what's in my tap?
 

Mick Frost

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For PH be sure to test your Tap twice, once right away and once after letting it gas off for 24 hours. I would advise against 50% water changes in general, especially on city water.
 

BobNJerry

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JaredK511 said:
About how much does the PH decrease after 24 hours?
that's why you are testing - to see how much the PH decreases on your tap after sitting for 24 hours.
 
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JaredK511

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Right, but is there a typical number for how much a PH will lower in general after 24 hours?
 

Mick Frost

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JaredK511 said:
I see. I also got a TDS meter to see how many come out of the tap. If that were to be really high would that negatively affect my fish with a large water change as well?
Depends on the levels of each contaminant. Calcium and Magnesium are a good thing in moderate concentration, Copper is perfect around 0.5ppm, Iron & Sulphur are bad in any reasonable amount.
 
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JaredK511

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So I got my TDS meter in today and it said I had 228 PPM in the tap and over 1400 in my show tank. Is that acceptable? My API test kit will arrive tomorrow so I can test the pH in both then. All fish are behaving normally.

EDIT - I just tested my other smaller tank (the one I had an issue with in original post) and the TDS reading in that one is 328.

The main show tank is fully planted with DIY CO2 and lots more fish. I assume the larger bioload in that is causing the huge spike as compared to my tap, correct?
 
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JaredK511

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OK, so I tested my water today. Here were the results:

PH
Fresh Tap - 8.2
Aged tap (more than 24 hours sitting) - 8
Tank - 7.8

Ammonia
.25 in tap
0 in tank.

I wasn't surprised the PH was so high but I expected the PH in my tank to be lower since it has a lot of driftwood and Indian Almond Leaves in it. I was surprised to see my tap has a little bit of ammonia in it. The test had a slight green tinge to it whereas the tank water was bright yellow.

So any recommendations for how I should best be doing my water changes going forward? Clearly I can't do 40%+.
 
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