Question: what do you want the pH to be long term?
Adding KH will quicken the depletion of the buffering capacity of the soil, and will raise the pH. That could be good or bad depending upon what livestock you are intending to add to the tank.
pH closer to 6.8 on average? Livestock-wise, nothing too extravagant: considering a betta, some Pygmy Corys or Otos, maybe some Ember Tetras. Wondering which snails or maybe some Cherry Shrimp.
I think you might be misunderstanding the kh/pH relationship?
Kh of 5 will make it very difficult to get to pH of 7.
And you said Hi-Tech? Are you testing pH of fully degassed water? What is your pH drop with co2 look like over the week? Also assuming you are testing pH of tap after it sits for atleast several hours? Some municipalities put chemicals in the water that artificially raise the pH. Not sure if Prime removes those?
Algae growth can be a result of many things but in a new tank it often times is too long of a light period. If you are over 6 hrs, I'd say drop it down for the short term.
My 10 gal tank runs at 1 kh, 6 Gh. Degassed pH runs around 7.1-7.2. Full co2, pH hovers around 6.0. Aquasoil substrate. Light is ramped with only 3 hrs full intensity, 6 hrs total. Tank has been running for over a year.
Seems like I might be misunderstanding the relationship of pH and kH. Happy to learn more. :-)
I tested de-gassed water about a week ago, but hadn’t started my official log book yet. If I remember pH was still about 6. Will check again at end of CO2 cycle today and pre-CO2 cycle in the morning for comparison.
Just tested days-old tap water: pH still 7.6
Light cycle - likely longer than it needs to be: Fluval Nano “Planted” set, dimmed across the spectrum by about 20%, shortened to 9 total hours but a 50% dip for about two hours in the middle of the day. The original set was about 2 hours longer than that.
Will bump it all back even more.
Getting back to pH, understanding that pH drops during the day from CO2 (I get that you’re not supposed to “chase” pH), what I’m missing is: why is it “supposed to” rise again overnight?
I’m concerned that (potentially - will have to measure more frequently) the only time I see pH toward a more “normal” range is with water changes. That was my thinking in adjusting the tap water accordingly to begin with.
Thanks in advance for anyone else’s thoughts and clarification.