How will pH, GH, and KH differences affect fish during water changes?

My tanks are only partially through the nitrogen cycles (10-gallon has been cycling for 15 days, 20-gallon only for 2 days), but I'm concerned about the changes I'm seeing in pH, GH, and KH results and how this will affect the fish during water changes. My tap water is hard: pH runs about 7.8, GH around 16, KH around 12. I had first started setting up my tank with EcoComplete but then realized that it was actually raising my pH (8.1) and likely my GH and KH as well, so I abandoned ship and started over with AquaSand. The AquaSand has had a completely opposite effect. At 15 days into cycling, my 10-gallon has a pH of 7.4, GH of 10, KH of 4. At 2 days into cycling, my 20-gallon has a pH same as the tap water still (7.8) but has already dropped in GH to 11 and KH to 10. My question is how to I go about water changes? Won't such differences between the tap water and tank water shock them? Should I add coral or something into the tank? Will these parameters level out a bit as the tanks continue through cycling or even go up at some point for some reason?

 

Relax a bit. A PH range of 7.4 - 8.1 is perfectly fine for the majority of commercially bred fish. A weekly 50% water change using your 7.8 PH tap won't move the needle up or down enough to harm anything.

 

Have you ever let your water out gas for 24 hours in a bucket and then test ?
How it comes out of you faucet is often buffed one way or the other by C02 added by the municipality ..It is not your natural readings .
take a bucket and set it aside for 24 hours and test..
I agree relax and if your testing says changing water is bad stop testing and just change water ..Seriously ..
Welcome !

 

I agree with with what the other members have told you so far. I also have hard water with a ph on the higher side. How do you do your water changes? If you use a python or similar product, I set the flow very low so it takes a long time to refill my tank, thinking the fish won’t be shocked. But I agree that we are probably just being over cautious.

 

What about the GH and KH? I'm totally new to fish keeping and water parameters seem to be quite important. Tell me to relax all you want, but let's be honest, I probably won't until I've got some healthy fish swimming around in the tanks for a good bit and I've got a bit of know-how and confidence in what I'm doing.

I haven't done any water changes yet since the tanks are cycling (10-gallon is 15 days into cycling and 20-gallon is only 2 days into cycling). I have just a regular siphon and bucket for water changes when I get to that stage. I'm not planning on letting the water sit for 24 hours before putting it into the tank, so I'm not sure how taking readings after letting it sit would be relevant. I mean, I can do it, but I'm not sure why...

 

What about the GH and KH? I'm totally new to fish keeping and water parameters seem to be quite important. Tell me to relax all you want, but let's be honest, I probably won't until I've got some healthy fish swimming around in the tanks for a good bit and I've got a bit of know-how and confidence in what I'm doing.

I haven't done any water changes yet since the tanks are cycling (10-gallon is 15 days into cycling and 20-gallon is only 2 days into cycling). I have just a regular siphon and bucket for water changes when I get to that stage. I'm not planning on letting the water sit for 24 hours before putting it into the tank, so I'm not sure how taking readings after letting it sit would be relevant. I mean, I can do it, but I'm not sure why...

Are you cycling these tanks with fish? What test kit are you using to test your water parameters?

 

Are you cycling these tanks with fish? What test kit are you using to test your water parameters?

No, I'm doing fishless cycling. I'm using API Master Kit for ammonia, nitrite, nitrate, pH and a separate API kit that just has GH and KH.

Substrate: AquaSand
Plants: variety of live plants and a couple betta bulbs just sprouting
Decorations: mopanI (relatively small in comparison to the tank size), dragon stone in the 20-gallon, a few small "aquarium" rocks and dragon stone in the 10-gallon, a betta log bobbing in the top of the 10-gallon
Filter media: filter floss, ceramic rings, intake tube sponge

 

I’m actually quite jealous of you, as I have to fight to raise my pH high enough for my Multifasciatus tank. If you’re worried about high pH, I recommend letting your water sitting in a bucket for a while as coralbandit said. You may also want to consider fish that prefer a higher pH. You could also use peat in your filter to lower your pH. I don’t recommend using products like pH up/down unless necessary, as they don’t keep your water parameters as stable as peat/crushed coral.

I’m actually quite jealous of you, as I have to fight to raise my pH high enough for my Multifasciatus tank. If you’re worried about high pH, I recommend letting your water sit in a bucket for a while as coralbandit said. You may also want to consider fish that prefer a higher pH. You could also use peat in your filter to lower your pH. I don’t recommend using products like pH up/down unless necessary, as they don’t keep your water parameters as stable as peat/crushed coral.

 

Ok your doing everything right! Honestly your hardness and ph isn’t as important as your ammonia and nitrite levels. Since your doing a fishless cycle, what are you using for an ammonia source?

 

Most who understand completely can't control their water parameters safely ..I know not one who can move KH without effecting ph and GH..
It is best to use the water you have the way it is given to you ..
Do the 24 hour test to find true pH..
Waterchanges are the secret to healthy fish [oh you don't have enough post for to me to really have said that..]
Nevermind !
My water from tap is 7.6 pH /2-3 KH /9 GH ..It works for my rams ,swordtails ,discus and super red plecos ..
How would you go about changing your water ? Buffers are a big no no ...

 

Ok your doing everything right! Honestly your hardness and ph isn’t as important as your ammonia and nitrite levels. Since your doing a fishless cycle, what are you using for an ammonia source?

Ammonia, the 10% stuff from Ace Hardware, though I didn't add any ammonia on setup since I detected some in both tanks (not sure if that was the right thing to do). I *think* my cycling numbers are doing what they're supposed to... I'm not entirely sure how often I'm supposed to be testing the water. I had been aiming for every 1-2 days but went out of town for a few more than that at one point, so here are my numbers so far:

10 Gallon
Nov 24: ammonia 0.5, nitrite 0, nitrate 5
Nov 25: ammonia 2, nitrite 0.25, nitrate 5
Nov 26: ammonia 4, nitrite 2, nitrate 2.5 (not sure why nitrate was lower here)
Nov 27: ammonia 4, nitrite 2, nitrate 5
Dec 2: ammonia 2, nitrite 2 to 5 (or higher? it became difficult to read starting at this point), nitrate about 17 (color was between 15 and 20)
Dec 3: ammonia 0.75, nitrite (same as Dec 2), nitrate 5
Dec 6: ammonia 0.25 so I dosed it back up to 4, nitrite (same as Dec 2), nitrate about 3 (color was between 0 and 5)
Dec 8: ammonia 0.25 so I dosed it back up to 4, nitrite (same as Dec 2), nitrate 5

20 Gallon
Dec 6: ammonia 0.75, nitrite 0, nitrate 4 (not quite the color of 5)
Dec 8: ammonia 4, nitrite 0.5, nitrate 3 (color was between 0 and 5)

I’m actually quite jealous of you, as I have to fight to raise my pH high enough for my Multifasciatus tank. If you’re worried about high pH, I recommend letting your water sit in a bucket for a while as coralbandit said. You may also want to consider fish that prefer a higher pH. You could also use peat in your filter to lower your pH. I don’t recommend using products like pH up/down unless necessary, as they don’t keep your water parameters as stable as peat/crushed coral.

Haha, you're not the first person to tell me they're jealous. So far I haven't even bothered to contemplate whether I'd prefer a higher or lower pH--I'm just trying to get through the cycling and then I'll take whatever I get. It's the GH/KH that keep decreasing that I'm unsure about. I guess I don't really know whether coral would affect GH/KH or just pH. Hmmm, probably time for some more researching...

I don't really have a place I can leave buckets with water to sit. I'm limited in how much I can lift, so I'd have to take 5-gallon buckets, only fill with 2-1/2 gallons so I could still move them and leave them sitting in the bathroom. I'd probably need two buckets for a water change on the 20-gallon (about 5 gallons total for WC) and a bucket for the 10-gallon (about 2.5-gallons for WC), right? That's not something that would work out in my house on a weekly basis.

I'm appreciating all the help I'm getting! Glad I started posting on this forum!

Sometimes I'm a little too wordy in what I say and then muddle up what I'm trying to say. I'm not really concerned about, nor wanting to change my pH. I actually hadn't even included that information when I first started writing my original post but then added the pH information before posting since pH goes hand-in-hand with GH and KH.

My real concern was/is this: When I pour the water from my tap that registers as a GH of 16 and a KH of 12 into my tank that registers as a GH of 10 and a KH of 4, will the fish notice? Yup, that's my question.

 

The reason for putting some water in a bucket and letting it sit for 24 hours before testing it is to put your mind to rest about the difference between what you are seeing straight from the tap and what you are seeing in your tank. In most cases there will be a difference and in most cases the difference isn't going to be a problem when you do your water changes. You may have to pour the water in slower during a water change but that's about it.