pH rises with water change

I haven't been here in a while, mostly because I haven't had any problems I know about enough to keep things stable, but not much more. now i'm suddenly having issues with the pH in my 29 gallon planted tank.

the pH has been generally stable around 6; I don't typically worry much about it, and I haven't been testing before and after each water change, but this week I changed out some fish (a few random tetras and minnows went into my stepsons' tank and I got a school of harlequin rasboras). it did raise the stocking level a little, from 90% before to just a touch over 100% now. (setup is on aqadvisor here: ) the tank has been established for almost a year. water parameters generally read: ammonia = 0, nitrite = 0, nitrate < 20ppm (varies a little depending on how good i've been with water changes).

the new fish gave me a little bit of an ammonia spike, up to about 1.0, which i've been controlling with water changes (<0.5). my cories are generally my "pH problem meters," because they seem to react first to pH changes. a big change in the levels makes them very sluggish. so when they started acting BLAH after water changes, I checked the pH. WHOA 8+. generally, adding a little Tetra easy balance plus helps if the pH goes wobbly, but this time, nope. still really high. my cories are sad.

I don't have a kH/gH test kit, so i'm not sure on those levels. I do know that the water comes out of the tap with a pH of 7-8 and reads ammonia up to 0.5, but this hasn't been a problem in the past - it balances out fast.

so what the...is the problem now? is it the frequency of the water changes (i've done three of ~50% in the past week)? is it the ammonia spike? how bad is this situation and will my tank settle down once the biofiltration evens out?

 

Your tank is going through a mini-cycle. Once the bacteria colony catches up and you again have no measurable ammonia or nitrite the pH should return to its normal level.

Do small daily water changes while the tank goes through the mini-cycle to help the fish survive it.

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ahhh...I figured that was the ammonia spike, didn't know it would make the pH act up too. thanks! I'll keep on as i've begun, then.

 

I'm not sure it's a good idea to be adding any chemicals to try and adjust your ph. I know most people on here do not recommend it. It will probably stabilize back out once the minI cycle settles back down.

 

yeah, i'd not planned to add any more. hopefully it'll settle down on its own.

I try not to regularly dose to alter pH. occasionally it's helpful if the pH out of the tap is very high - the tank is generally stable, but the tap water is always on the high side comparatively (sometimes really high) and I hate to do a water change and dump a bunch of high pH water into the tank.

 

A stable ph is better than trying to control it. My ph out of the tap is 8.2 and remains pretty close to that all the time and I don't have any issues. Most other people on here usually say the same thing. I wouldn't worry about your ph as long as its stable.

 

it's not a worry, usually - just curious...does your tank stay at 8.2? mine doesn't - it usually stabilizes around 6-6.5, and then when I do a water change, it goes up some - generally comes back down to the 6 range. if it goes up a whole lot, I think my fish are uncomfortable with the sudden change it generally comes back down, though, so maybe I shouldn't worry on the rare occasions that it happens.

the last place I lived was on well water, and it would come out of the tap at 8 and the tank would stay at 8 - but once we moved, we were on municipal water, and the pH in the tank is never as high as the pH out of the tap. probably the buffering capabilities of the water here, but that part of chemistry i'm a little vague on. I don't usually worry at all, as the tank is almost always stable on its own, except when the tap water is *very* high, which happens rarely...I think i've added the tetra easy balance plus twice or three times in the past year.

 

No my tank water doesn't go below 7.8. Usually stays at 8 though. I have some driftwood that lowers it some, naturally. Do you have a lot of driftwood in your tank? What are you using for water treatment during water changes? If its Prime and you are testing your water less than 24 hours after adding the Prime then it will cause false readings. That does seem very strange for it to drop that low. Is your tank planted, are you adding CO2?

 

the tank is planted, a couple of anubias and one thing I picked up ages ago and can't remember the name of, but there's a lot of it. (just scanning s on google, it might be moneywort.) no c02. I do have a good-sized piece of driftwood.

when I do water changes, the only thing I add is Dechlor. I try to keep the water changes small and weekly, but once or twice when i've gotten really busy it's gone a few weeks before I realize that I haven't managed the fish tank in a while, and then I change a bit more water than usual.

generally I don't test the pH of the tap water before water changes, so my first hint is "cories are looking groggy." if I see that, I check the pH in the tank, and sometimes I check the tap to see if it's suddenly very high. I add some of the tetra safe balance + if both of those things are true, and everything usually evens out in a very short amount of time.

the mini-cycle explains why the safe balance+ didn't work this time, I guess...but doesn't explain why my pH is so low, unless it is the driftwood. that would make sense...I guess it's a pretty big chunk for the size of the tank.

[edited for clarity ]

 

Driftwood will lower your ph, but I'm not sure that much. Maybe though. What kind of dechlorinator are you adding? What's the name of it?

 

it just says Dechlor, green bottle, the back says Weco Products in fine print.

and out of curiosity, I just checked the pH again - 8 hours after I changed the water and got a reading that was nearly off the chart on the high pH (at least 8.0 this morning, and that was a pretty intense violet I was getting), it has dropped to ~7. so something is causing it to head back where it usually is, which I suppose is good.

maybe next time I'll test it frequently after a water change and see if it is the driftwood. it doesn't make sense that my very occasional use of the safe balance + is keeping it stable at 6 all on its own.

 

You should try using Seachem Prime. It is very good and most everyone on here uses it. Probably want help with your ph, but it will detoxify ammonia and any other heavy metals.

 

To test the "true pH" reading of your tap, put some in a bucket with an airstone and test in 24 hours. This may answer some questions. it also depends on the buffering. If you have 0 KH when you test your tap & even though your pH is 8.0 it will drop down to 6.0 as you've got nothing to stablize it. Smaller & more frequent water changes need to be done. Get your tank cycled first and see where it stablizes at.