Planted community aquarium buffer for PH

[Herefishyfish12]

I have a 10 gallon sorority tank 5 female bettas, one flying fox, PH - 6.0 AM - 0 NITRITE -0 NITRATE- 10 functioning for 6 months. The plants are growing, bananna lily has 3 lily pads, amazon sword growing, java moss growing, anubius growing, feed root tabs occasionally, light is led blue/white 4 to 6 hours a day. Ph outta tap 6.5. Usually I can water change once a week to keep nitrates down and ph stable, but the last month the ph is dropping. Bottoming out to 5.0. Bettas no happy so I've been investigating... I looked into soft/hard water. Hypothesis is over time I've worn out my buffer, bc not really fertilizing plants, kinda letting fish do it, city water and no minerals, I do gravel vac gravel only tank, but I don't near my plants bc I put the root tabs and let the fish fertilize my plants. So, how do I gain back buffer in aquarium w/o swinging ph. What will allow it to even out and hold stable ph. Lemme know what I don't. Please and thank ya 🙃

[Scapexghost]

Crushed coral or seachem equilibrium. There are a million others but those work well

Edited January 30, 2023 by Scapexghost
Til coop sells equilibrium

[here fishyfishy]

Thanks a bunch, will argonite suffice?  that's all I have access to where I'm located

[Cory]

I recommend Crushed coral as well. I find aragonite to slow to react. Takes much more to accomplish the same effect. Also equilibrium affects hardness but not pH.