geofari

I was planning on using my tap water for a water change on my 20g but the thing is that the pH in my tank is at a remarkable 7.0 whereas my tap is 7.8 or higher. Let's say I replace 5 gallons worth of water, does this drastically change my tank?

aquarist48

Hello Geofari. Welcome to Fish Lore! Your tap water will raise the pH in your tank since it is higher. As to how much it will raise it, it's hard to say. The best way to get a true pH level from your tap is to place some water in a bucket and let it set for 24 hours then test it.

It's been my experience that you can raise the pH in your tank with out too much concern. It's when you lower the pH to drastically that causes problems and even fish loss. Add the water slowly (neons can be a bit sensitive especially in newly established tanks, they aren't a species I recommend for beginners) and you should be fine.

Best of luck and I hope you enjoy the site.
Ken

Shawnie

thats a tough one because letting the water sit, lets you get a true ph but also lets the water get cold...adding cold water to a tank, can cause major shock....adding a large water change, will cause a ph shock..up or down it would be too drastic..but I think a 5-10% change would be fine and wouldnt change the ph too drastically to cause any problems ...

ray_sj

You can follow Ken's suggestion to find out to true pH of your tap water. If you find the pH is much different from your tank, you can make small water changes. The resulting pH change in your tank is basically the % of water you changed times the total pH difference.

I have a similar situation, except my water starts at 7.6 right out of the tap, but the true pH is closer to 8.2. If I have to change a lot of water, I will put water (2 degrees warmer than my actual tank temperature) in a 5 gallon bucket, and aerate it for 4 hours with a powerhead. The aeration accelerates bringing the tap water to its true pH. This way, I don't have any problems with the water being too cold for the tank.

geofari

Well, I ended up doing a 25% water change and the water I used was 3/4 tap water and 1/4 rain water for kicks and giggles. pH went up .2 so alls is good

aquarist48

Glad to hear it Geofari!
Ken