Do plants affect pH?

[drmommacat]

My tap water is 8. In the beginning when I started my tanks I was adding the pH 7 powder from API, and after cycling it held steady for six months at 6.8-7.0. Then after I added plants, the pH dropped. So for the past 3-4 weeks I have not added any pH stuff to the tap, just the water conditioner (Prime and Stress Coat). I do 30-50% changes once a week. The pH will go up a little, like to 6.4-6.6 for a few days then drop to 6 again. I did water changes today, on all three tanks. pH readings before were 6.0 in the 92, 6.6 in the 29, and 6.0 in the 26. After the changes both smaller tanks were 6.6. Forgot to do an after pH in the 92. I'll see what happens over the next couple days.

[Lady Hobbs]

No need to add Stress Coat and Prime. Both are water conditioners and both have the same purpose.

[drmommacat]

So just a follow up on the pH issue. 24 hours after a 50% water change in all tanks, with the pH around 6.6 after the changes, and the pH is down to 6.0 in the 92gallon, 6.4 in the 29, and 6.0 in the 26.

So something is driving the pH down, and since the only thing that has changed is the plants, seems like that's the culprit?

I am going to try addidng some crushed coral to the filter and see if that regulates it a bit. Anyone have any reason why that's a bad idea?

Thanks again!