How to increase buffering/alkalinity (KH) but maintain pH

[curviceps]

Hi there

Currently, I have my pH at roughly where I want to maintain it - around 6.6, using peat.

However, my alkalinity (carbonate hardness) is at 1 dKH. I am a bit concerned about the potential for pH crash given that pH buffering capacity is very low.

I do water changes once a week. However, from time to time, I need to travel and am worried I might have a pH crash if I am not able to provide the weekly water changes.

Firstly, should I be concerned?

Secondly, how could I increase the alkalinity to say, 4 dKH. Without surprise, increasing KH at the moment will and has increased my pH, given the level of CO2 in my water.

What should I do to get better buffering without increasing pH. I think I know the options - a) use phosphate buffer, b) use CO2 - but not sure how to proceed as both has its downside.

a) Phosphate buffers - my tank is mostly silk plants with a little bit of java moss and potentially a little bit more of anubias nana in the future. Phosphate buffers seem to be the easiest option, but will I have problems with algae?

b) CO2 - expensive and tedious given I don't really need this for plants, just for pH control. Any suggestions on a "minimal" setup that is cheap and does the job?

c) Any other options or suggestions?

Cheers
Tim

 

[Mike Wise]

The dKH out of my tap is <1º. As long as my tanks get regular weekly water changes, light feedings, and low population density, I have no pH crashes.

 

[lemonlime]

Ah, a question I may be able to help with! I've be researching plantedaquaria a lot the past few weeks.. so heres my answer!

To raise kH use baking soda (sodium bicarbonate). One teaspoon will increase the kH of 50 liters of water (13 gallons) by 4 degrees (68 ppm). ... some arithmetic will be involved

The addition will have no major effect on the pH.. but test ..perhaps a tenth or so..
no affect on gh.. of course

note: sodium bicarbonate contains sodium duh, which isn't good for fish in quanity..but a few dkh points would be fine!

As Mike pointed out, with normal maintenance and proper feeding etc a ph crash is unlikely... You are fortunate to have such soft water!
My city buffers our water with orthopolyphosphates to a kh of ~3