Originally Posted by mr.bigglesworth
..In other words, going from 7.0 to 8.0 or 8.0 to 7.0 you are multiplying or dividing the hardness in your water by 10!!!
This is 100% true - but hardness is the wrong term to use. Hydrogen concentration is better.
The slow way of determining a stable CO2 is the pH drop test
. Take a cup of water from your tank and measure its pH. Leave it on a table (or wherever you want) and then measure the pH 24 hours later. Now here's the trick..
If your pH BEFORE the 24 hours was 7.0 and after the 24 hours it has dropped by exactly 1pH (so it's now 6.0) then you have EXACTLY 30ppm of CO2 which is what you want. Research this for more details and what to do if the pH drop is higher or lower than 1pH.
Or use a drop-checker --> lime-green colour = 30ppm of CO2.
If the drop-checker is blue then not enough CO2 so turn up your needle valve to allow a tiny bit more CO2 in. Wait a few hours and see what the colour is. If it's yellow, turn it down. Once you get a lime-green drop checker.. that's it - leave the CO2 regulator to do its job
pH controllers change the pH by changing the CO2 levels constantly. This is not good and can cause algae - it may not be causing the algae in your photos but it can cause to algae outbreaks over time.
A standard CO2 bottle with a regulator and a solenoid (a bubble counter is helpful too) will create a stable CO2 level. Search the forums regarding pH controllers - you'll see what I mean.
I know it's probably a lot to take in but research, research, research and continue to ask as many questions on this forum to get the answers you need. Make sure you don't take one persons point of view as the right view, get other peoples views too and make up your own mind. Setting up my planted tank has been a ballache with all the algae problems, slow growth in plants, dying plants, dead fauna etc. But everyone gets there in the end!
Best of luck
Planted Tank Enthusiast
80L Opti White heavily planted open-top tank: JBL CristalProfi 1501e containing a range of filter media; EI dosing; pressurised CO2 with Lily Pipes and Surface Skimmer; Finnex Planted+ LED Light. Neons, Embers, Pygmy Corys, Amano's and Oto's ..and I'm in love with it.
If I have helped you or require further information / advice, then please do not hesitate to drop me a message!