Ph Is Changing

[kcharley]

The PH of my tap water has changed from 7.6 to 8.8 in the last week.

I have two concerns.

My first concern is the effect this will have on my son's established tank. Its PH has been steady at 7.4. When I do the weekly 25% water change should I expect the PH in the tank to be 7.8? Higher? Lower? At what point is this too big a swing for his fish.

My second concern is I just started cycling a second tank. (This is how I found the PH change.) Will this high of a PH affect the cycling?

I'm trying to find some hardness tests to see if the PH swing is possibly due to very soft water.

Thanks in advance for any help.

 

[rdd1952]

Have you recently added anything such as rocks to the tank? I can't think of anything that would make it go up that much unnless it is a lime based rock or something. I guess it could be the water company too. You might want to let soe tap water sit for 24 hours and then test it.

The fish can probably handle the pH as most can readily adapt to a stable pH. I don't think you will see any problems from the swing but some fish will probably be less than comfortabe in it.

As far as the cycling is concerned, from what I have read, optimal pH for cycling is between about 7 and 8 so you may experience difficulties in cycling with a pH that high.

 

[dcarmor927]

Thats a big swing of pH...more than a .2 pH change a day can be harmful to fish...
The high pH shouldn't affect your cycle, but im not 100%...if it gets too low it can cause problems tho...
Maybe you could contact your water distributor or whatever and diagnose the problem...
Also look into a pH adjuster kit that you could ad to the water before you dump it into the tank so that the pH change isnt too large...

 

[rdd1952]

I would steer clear of the pH adjusters as they just keep the pH in a constant up and down swing. Better to have it a little high and stable than constantly changing.

 

[kcharley]

Thanks rdd and dcarmor.

All that is in the tank right now is the filter and the heater. As I recently resealed it, I am cycling it in the garage in case it leaks. Four days and no leaks yet.

I thought it was the tank until I tested the tap water. I've read that low hardness can cause PH swings so I'm looking for GH and KH tests but haven't found them yet. I'm hesitant to try PH adjusters until I know why the PH is so high.

Good idea on calling the water company. I'll call them tomorrow.

 

[dcarmor927]

good point, and if rdd says to steer clear, id take his word...good luck!!

 

[waterdrop]

I can vouch for the TetraTest KH test kit being good. Also there is an API GH/KH test kit where the KH test is very similar.

~~waterdrop~~

 

[kcharley]

Thanks WD. I'll check some different pet stores tonight for those.

The local water district had some interesting comments. They claim they hold PH between 9.1 and 9.5 with 140 mg hardness for health and corrosion reasons. (So how was I getting 7.6 during the summer? ) Their first thought was my API kit wasn't accurate. They then said it can make a big difference between cold and hot water, especially as temperatures drop due to the season. That might explain the difference as I have typically tested the tap water after I have come to a blended temperature. The current high readings have been straight cold water. I can't imagine why it would affect the PH reading but my high readings have come from a different faucet in the house.

I'll post the results after I get home tonight.

 

[kcharley]

Thanks WD. I'll check some different pet stores tonight for those.

The local water district had some interesting comments. They claim they hold PH between 9.1 and 9.5 with 140 mg hardness for health and corrosion reasons. (So how was I getting 7.6 during the summer? ) Their first thought was my API kit wasn't accurate. They then said it can make a big difference between cold and hot water, especially as temperatures drop due to the season. That might explain the difference as I have typically tested the tap water after I have come to a blended temperature. The current high readings have been straight cold water. I can't imagine why it would affect the PH reading but my high readings have come from a different faucet in the house.

I'll post the results after I get home tonight.

I'm not sure what tonight's test results teach me.

Day 3 of fishless cycle and PH dropped from 8.4 to 8, The ammonia level may be dropping a little as the green doesn't seem quite as intense but I still call it at 4.0. (I did add some established media from another tank on day 1.)

The tap water tests at 8.4 PH regardless of hot, cold or a different faucet in the house. I tested my son's tank for PH and it is holding steady at 7.4. If the local water company is really holding PH in the 9.1 - 9.5 range, something must be happening to it in route especially on a seasonal basis.

I found an API GH and KH liquid test kit tonight. The new tank has KH of 5 and GH of 7, so soft water can't be accounting for an unstable PH.

When I do this weeks water change on my son's aquarium, I'll hold it to 20% max and see what happens to the PH.

I really am wondering about an RO unit.

 

[petertr]

Water company holding pH at over 9 <shock>

 

[OldMan47]

It depends a lot on what your water company is using to raise the pH. If they are using volatiles, the pH will drop as soon as the water is set out in a bucket for a few hours. If they are using some kind of solid buffer, I would expect the pH to stay high. The value they are putting into the pipes is relatively soft water, mine runs twice that high in total dissolved solids. Try setting a bucket of water out overnight and then test the pH. My guess is it will be less than 8.0 by morning which means that any bump it gives your tank will be short lived and could be overcome just by drawing the water a day before you need it. Controlling for high pH is sometimes done to minimize the amount that the pipe in the mains dissolves into the water. If it is old pipe that may contain lead or similar contaminants, it would not be unusual to intentionally drive the pH high to make the water safer at the consumer's end of the pipe.

 

[kcharley]

It depends a lot on what your water company is using to raise the pH. ....... Try setting a bucket of water out overnight and then test the pH. My guess is it will be less than 8.0 by morning which means that any bump it gives your tank will be short lived and could be overcome just by drawing the water a day before you need it. Controlling for high pH is sometimes done to minimize the amount that the pipe in the mains dissolves into the water. If it is old pipe that may contain lead or similar contaminants, it would not be unusual to intentionally drive the pH high to make the water safer at the consumer's end of the pipe.

Thank you.

The water company did mention something about pipe corrosion. Your explanation/observation makes more sense than theirs. I did leave a gallon out overnight with some prime in it. I'm not really sure why I did, I just did. It will be interesting to see what it tests tonight.

I think I will draw some water tonight into a spare 10 gallon acquarium to use for tomorrow's water change in the established acquarium. My little boy really likes his fish and is sad when one dies.

As an aside, my son is showing good responsibility in caring for his fish. He is feeding them the proper amounts (after our initial overfeeding mistake), observes their behavior for healthy and unhealthy signs and helps with the water changes. He even helped me build the cabinet that this next aquarium will go on.

Thank you all for a great site. We really appreciate your helpfulness, encouragement and support.

 

[rdd1952]

As a general rule (not always the case but usually), water with a high pH will also have a high GH & KH. They just go hand in hand. As mentioned, it really depends on how the water company is bumping the pH up. The number they say they are keeping it seems extremely high. In the US, it seems that most try to keep it as close to neutral as possible and also tend to keep the GH & KH as low as possible too if for no reason than to make it taste better.

As an aside, my son is showing good responsibility in caring for his fish. He is feeding them the proper amounts (after our initial overfeeding mistake), observes their behavior for healthy and unhealthy signs and helps with the water changes. He even helped me build the cabinet that this next aquarium will go on.

I think it is great when kids get involved in the hobby. It is a great way for them to learn responsibilities that will help them later in life.

 

[kcharley]

As a general rule (not always the case but usually), water with a high pH will also have a high GH & KH. They just go hand in hand. As mentioned, it really depends on how the water company is bumping the pH up. The number they say they are keeping it seems extremely high. In the US, it seems that most try to keep it as close to neutral as possible and also tend to keep the GH & KH as low as possible too if for no reason than to make it taste better.

Strikes me also as high, but the local water tastes great. It recently got a second place finish in a national competition between water districts. From their website the water is moderatly hard at 140. The source river water is 250. They stop at 140 due to cost considerations.

After re-reading Oldman47's comments, I pulled the following from the water district website:

"Lime and/or soda ash are mixed with the water in these tanks to soften it. They combine with the hardness of the water to form a precipitate which settles out. The removal of solids in the settling process is one of the most visible in the treatment process. One can see a cloud of solids at the bottom of the basins which is distinct from the clear water above it.

Coming out of the first clarification basins, the pH is high due to the lime softening process. Carbon dioxide, added at this point to lower the pH, makes the water stable and non-corrosive."

Elsewhere in their website it states that the remaining hardness is caused by calcium and magnesium salts and that they do encounter seasonal difficulties as a large portion of the water comes from the Kansas and Missouri rivers.

Day 4 of the cycle and the tank PH test isn't a strong match for any of the chart colors. Seems to be between the 7.8 and 8.0 readings. (Ammonia is steady at 4.0 and nitrite is zero.)

The gallon I drew last night still shows 8.4.

I should do a partial water change on my established aquarium tomorrow night. I think I will buy some RO water and mix it with tap to get close to my existing 7.6. I'm hesitant to use chemicals as I am not sure the result will be stable.

I do appreciate everyone's comments and help. Thank you all very much.

 

[rhostog]

I'd definitely agree that adjusting the pH with chemicals is not a good idea - IME the pH reverted overnight.

If you do use RO water in a tank containing fish, I think you are right to keep the water changes fairly small initially - your RO/tapwater mix may have a different hardness and concentration of other minerals compared with your tank water, and fish can be stressed by sudden changes in hardness as well as by pH changes.

Good luck!